Large-Scale Load Tests and
Data Base of Spread Footings
on Sand
PUBLICATION
NO. FHWA-RD-97-068
U.S.Deportment of Transportation
Feded Hlghway Admtnistration
Research and Development
Turner-Fairbank
Highway Research Center
6300 Georgetown
Pike
McLean, VA 22101-2296
NOVEMBER 1997
FOREWORD
This report, “Large-Scale Load Tests and Data Base of SpreadFootings on Sand”, documents
researchwhich had a goal of improving the reliability of designrules for spreadfootings;
accomplishmentof the goal was seenas a way of increasingthe confidenceof engineersin the
judicious use of spreadfootings insteadof deep foundations,thus effecting economiesin
foundation engineering.
The researchincluded: 1) the developmentof a data basefor spreadfootings, including case
histories and load tests, 2) evaluation of the performanceof large-scalefootings in sand,
3) evaluation of accuracyof footing performanceprediction methods,and 4) new prediction
methods.
The report will be of interest to engineersand technologistschargedwith the design and
construction of foundations.
;&Jfif!i$YL$Y&.$Z
mers, P.E.
Director, Oflice of Engineering
Researchand Development
NOTICE
This document is disseminatedunder the sponsorshipof the Department of Transportation in the
interest of information exchange. The United StatesGovernmentassumesno liability for its
contents or use thereof This report does not constitute a standard,specification, or regulation.
The United States Government does not endorse products or manufacturers. Trademarks or
manufacturers’ names appear herein only becausethey are considered essentialto the object of
this document.
Technical Report Documentation
Report
1. Report No.
1 2. Government Accession No.
FHWA-RD-97-068
I
1 3. Recipient’s Catalog No.
!
4. Title and Subtitle
LARGE SCALE LOAD TESTS AND DATA BASE OF
SPREAD FOOTINGS ON SAND
6. Performing Organization Code
14G604
8. Performing Organization Report No.
7. Author(s)
Jean-Louis BRIAUD and Robert GIBBENS
10. Work Unit No. (TRAIS)
9. Performing Organization Name and Address
Texas A&M University
Civil Engineering Dept.
College Station, Texas 77843
GeotestEngineering, Inc.
5600 Bintliff Drive
Houston, Texas 77036
3E3A0291
11. Contract or Grant No.
DTFH6 1-92-2-00050
12. Sponsoring Agency Name and Address
13. Type of Report and Period Covered
Federal Highway Administration, HNR 10
Turner Fairbank Highway ResearchCenter
6300 GeorgetownPike
McLean, Virginia 22 101
Final Report
14. Sponsoring Agency Code
15. Supplementary Notes
Contracting Officer’s Technical Representative(COTR): A.F. Dimillio
FHWA Technical Consultants: M.T. Adams, R. Cheney and J. Dimaggio
Contractor Project Manager: V.N. Vijayvergia
16. Abstract
Spread Footings are most often less expensive than deep foundations. In an effort to improve the reliability of spread
footings, this researchproject was undertaken. The results consist of
1.
2.
3.
4.
5.
6.
A user friendly microcomputer data baseof spreadfootings, casehistories and load tests.
The performance of five large scale squarefootings in sand.
An evaluation of the current accuracy of settlementand bearing capacity prediction methods.
Observations on the scale effect, the zone of influence, the creep settlement,and soil heterogeneity.
A new and simple method to predict the complete load settlementcurve for a footing as well as several correlations.
Evaluation of the WAR test, a dynamic test for spreadfootings.
17. Key Words
18. Distribution Statement
Spreadfootings, load tests,data base,sand, in situ
testing, instrumentation, dynamic testing, finite
element analysis, shallow foundations.
No Restrictions. This document is available to the
public from the National Technical Information
Service, Springfield, Virginia 22 161
10. Security Classif. (of this report)
20. Security Classif. (of this page)
Unclassified
Form DOT F 1700.7
Unclassified
(8-72)
Reproduction
21. No. of Pages
228
of completed page authorized
22. Price
UNIT CONVERSIONS
9.81 m/s2 = 386.22 in./s2 = 32.185 ft/s2, Paris: g = 9.80665 m/s2 London: g = 3.2174 x 101 ft/s2
Area
1 m2= 1.5500x 103in.2= 1.0764x 101 ft2= 1,196yd2= 106mm2
= 104 cm2 = 2.471 x 10-4 acres2= 3.861 x IO-7 mi2
Coefficient of
Consolidation
lm2/s = 104 cm2/s= 6 x 105 cm2/min = 3.6 x 107 cm2/h
= 8.64 x 108 cm2/day= 2.628 x 1010cm2lmonth
= 3.1536 x 1011cm2/year
= 1.550x 103 in.2/s = 4.0734 x 109 in.2/month
= 1.3392x 108 in.2/day = 4.881 x 1010 in.2/year
= 9.4783 x 105 ft2Iday = 2.8830 x 107 ft2/month
= 3.3945 x 108 Et2/year
Flow
1 m3/s = 106 cm3/s= 8.64 x 104 m3/day = 8.64 x 1010 cm3/day
= 3.5314 x 101 f@/s= 3.0511 x 106 ft3/day
Force
10 kN = 2.2482 x 103 lb = 2.2482 kip = 1.1241t (short ton = 2000 lb)
= 1.0194x 103 kg = 1.0194x 106 g = 1.0194T (metric ton = 1000 kg)
= 109 dynes = 3.5971 x 104 ounces= 1.0221t (long ton = 2200 lb)
Force per Unit
Length
1 kN/m = 6.8526 x 101 lb/ft = 6.8526 x 10-2 kip/ft
=3.4263x lo-2t/ft
= 1.0194x 102 kg/m = 1.0194x 10-l T/m
Length
1 m = 3.9370 x 101 in. = 3.2808 ft = 1.0936yd
= lOlOAmgstrom= 106microns= 103mm= 102cm
= 10-3 km = 6.2137 x 10-4 mile = 5.3996 x IO-4 nautical mile
Moment or
Energy
1 kN.m = 7.3759 x 102 Ib.ft = 7.3759x 10-I kip.ft = 3.6879 x 10-l t.ft
= 1.0194x 103 g.cm = 1.0194x 102 kg.m= 1.0194x 10-l T.m
= 103N.m = 103 Joule
Moment of
Inertia
1 ,4=2.4025x 106in4= 1.1586x 102ft4=6.9911 x IO-1yd4
= 108 cm4 = 1012mm4
Moment per
Unit Length
1 kN.m/m = 2.2482 x 102 lb.ft/ft = 2.2482 x 10-l kip.ft/ft
= 1.1241x 10-l t.f?/fi= 1.0194x 102 kg.m/m = 1.0194x 10-l T.m/m
Pressure
100 kPa = 102 kN/m2 = 1.4503x 101 lb/in.2 = 2.0885 x 103 lb/ft2
= 1.4503x 1O-2kip/in. 2 = 2.0885 kip/ft2 = 1.0442t/ft2
=7.5003x10~cmofHg(OoC)=l.0197kg/m2=l.0l97x1O~T/m2
= 9.8689 x 10-l Atm = 3.3455 x 101 ft of H20 (4” C)
= 1.OOOO
bar = I 06 dynes/cm2
Temperature
Time
1 yr. = 12 mo. = 365 day = 8760 hr = 5.256 x 105 min = 3.1536 x 107 s
Unit Weight, Coefficient
of SubgradeReaction
10 kN/m3 = 6.3654 x 101 lb/ft3 = 3.6837 x 10-2 lb/in.3
= 1.0196g/cm3 = 1.0196T/m3 = 1.0196 103 kg/m3
Velocity or
Permeability
1 m/s = 3.6 km/h = 2.2369 mile/h = 6 x 101 m/min = 102 cm/s
= 1.9685x 102 ft/min = 3.2808 ft/s = 1.0346 108 ft/year = 2.8346 x 105 ft/day
Volume
1 m3=6.1024x 104in.3=3.5315~ 101 ft3= 1,308yd3= 109mm3= 106cm3=103dm3
= 103 liter = 2.1998 x 102 gallon (U.K.) = 2.6417 x 102 gallon (U.S.)
Volume Loss in a Tubing
1 cm3/m/kPa= 8.91 x 10-4 in.3/ft/psf
TABLE OF CONTENTS
Page
1.
SUMMARY ............................................................................................
GOALS. .......................................................................................
1.1
RESULTS .....................................................................................
1.2
2.
INTRODUCTION .....................................................................................
3.
SHALDB: DATA BASE OF SPREAD FOOTINGS .............................................
3.1
THE DATA BASE FILES ..................................................................
3.1.1 General Information ......... .......................................................
3.1.2 Footing Data ........................................................................
3.1.3 Footing Behavior...............................................................................
3.1.4 Soil Data.. ..........................................................................................
3.1.5 SettlementPredictions.......................................................................
3.1.6 Case Histories Listed in the Data Base.................................................
3.2
THE DATA BASE PROGRAM ......................................................................
3.2.1 System Requirements.........................................................................
3.2.2 Installation ............................................................................................
3.2.3 The Maintenance Section......................................................................
3.2.3.1
Adding a New Case History.. .............................................
3.2.3.2
Modifying an Existing Case History ....................................
3.2.4 The Inquires Section.............................................................................
3.2.4.1
The ParameterBased Search...............................................
3.2.4.2
Viewing a Footing...............................................................
3.2.5 The Data Analysis Section....................................................................
3.2.5.1
Background Calculations....................................................
3.2.5.2
Unit Conversions................................................................
3.2.5.3
Averages and Standard Deviation........................................
3.2.5.4
Unit Weight and Overburden Pressure................................
3.2.6 SettlementPrediction Methods..............................................................
3.2.7 Data Analysis.. ......................................................................................
10
10
10
11
11
11
12
13
15
16
16
17
18
18
20
20
21
21
21
21
22
22
23
25
4.
LOAD TESTING OF FIVE LARGE-SCALE FOOTINGS ON SAND. ........................
4.1
LOAD TEST SETUP .......................................................................................
4.1.1 Spread Footing Construction.................................................................
4.1.2 Reaction Shaft Construction..................................................................
4.1.3 Horizontal Displacement Measurements(Inclinometers)........................
4.1.4 Vertical Displacement Measurements(Extensometer)............................
4.1.5 Footing Displacement Measurements.....................................................
4.1.6 Load Measurements...............................................................................
26
26
26
28
28
31
31
33
. ..
111
8
TABLE OF CONTENTS (continued)
Page
4.2
4.3
SOIL INVESTIGATION ..............................................................................
General Soil Description .........................................................................
4.2.1
4.2.2
Laboratory Tests....................................................................................
4.2.3
Field Tests.............................................................................................
Standard Penetration Tests w/ Energy Measurements..............
4.2.3.1
4.2.3.2
PiezoConePenetration Tests..................................................
4.2.3.3
PressuremeterTests................................................................
4.2.3.4
Dilatometer Tests....................................................................
4.2.3.5
Borehole Shear Test................................................................
4.2.3.6
Cross-Hole Wave & Step Blade Tests....................................
RESULTS .....................................................................................
4.3.1
Load SettlementCurves............................................................
4.3.2
Creep Curves........................................................................
4.3.3
Inclinometer Profiles................................................................
4.3.4
Telltale Profiles ......................................................................
33
33
33
35
36
36
36
39
39
39
39
39
39
41
47
5.
COMPARISON BETWEEN PREDICTED AND MEASURED RESULTS ..................
5.1 PREDICTION SYMPOSIUM EVENT USING THE FIVE FOOTINGS ............
5.1.1
Introduction. .........................................................................
5.1.2
The Prediction Request.............................................................
5.1.3
Prediction Results and Comparisons..............................................
5.1.4
Predicted Design Loads and Factor of Safety....................................
5.1.5
General Observations...............................................................
5.2
EVALUATION OF 18 PREDICTION METHODS USING THE FIVE FOOTINGS
5.2.1
SettlementPrediction Methods......... ...........................................
5.2.2
BearingCapacityMethods.........................................................
5.2.3
Best Method ..........................................................................
51
51
51
51
52
62
63
67
68
69
69
6.
WAR
6.1
6.2
6.3
71
71
75
75
TEST . .. . . . . . . .. . . . . . . . . .. . . . . . . .. ..I.... . . . . . . . . . . . . **...**...* . . . . . . . . .. . . . . . . .. . . . . . ..I...... . . .
PROCEDURES . ..+.......** . . . .. . . . . . . . .. . . . . .. . . . . . . . . . . *...**...* . . . . . .. . . . . . . .. . . . . .. . . . . ..
DATA ANALYSIS.. . .. . ... .. . ... . .. ... ... 4..... ... ... ... ... ... ... ... . ,. ... ... ... . .. ... . .. .. . .
COMPARlSON WITH LOAD TESTS. ,. . . . ,.. , ., ., . . . .,a. . . . . , , .. . . . . . ,. . ., , . . . . , . . . . , , ..
7.
ANALYSIS OF THE DATA ...........................................................................
7.1
SCALE EFFECT., .............................................................................
7.2 CREEP SETTLEMENT ......................................................................
7.3
STRAIN VERSUS DEPTH ..................................................................
7.4
SOIL MASS DEFORMATION .............................................................
8.
NEW
8.1
8.2
8.3
LOAD SETTLEMENT CURVE METHOD ................................................
THE IDEA .....................................................................................
DEVELOPEMENT OF THE METHOD ..................................................
STEP BY STEP PROCEDURE ............................................................
iv
83
83
89
92
95
_-
100
100
101
108
TABLE OF CONTENTS (continued)
Page
CONCLUSIONS .........................................................................................
111
APPENDIX A: Soil Data....................................................................................
117
APPENDIX B: Load SettlementCurves...................................................................
159
APPENDIX C: Creep Curves...............................................................................
170
APPENDIX D: Inclinometer Results... :, ..................................................................
193
APPENDIX E: Telltale Results,,.........................................................................
209
REFERENCES................................................................................................
214
9.
LIST OF FIGURES
Page
Figure
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
4.13
4.14
4.15
4.16
4.17
4.18
4.19
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
Footing/Pier Layout .................................................................................
Load Test Setup....................................................................................
In Situ Field Testing Layout with Auger Hole Location., .....................................
Cross Sectional View of Telltale ..................................................................
General Soil Layering ..............................................................................
Grain Size Analysis ..............................................................................
Range of STP Results..............................................................................
Range of 5 CPT Soundings........................................................................
Range of PMT Results.............................................................................
Range of DMT Results...........................................................................
Range of BHST Results..........................................................................
30-Minute Monotonic Load SettlementCurves for All Footings............................
Individual Creep Exponent Curves for 1.5-m Footing, 1.34 MN - 2.80 MN ...............
Individual Creep Exponent Curves for 1.5-m Footing - 24-Hour Creep Test...............
Individual Creep Exponent Curves for 3.0-m(n) Footing, 6.23 MN - 10.24 MN ............
Individual Creep Exponent Curves for 3.0-m(n) Footing - 24-Hour Creep Test ...............
Inclinometer Test - 1.78~MN Fail Load - N-S Direction, 1.0-m Footing ........................
Inclinometer Test - 8.90~MN Fail Load - N-S Direction, 3.0-m Footing ........................
SettlementVersus Depth for 3.0-m(s) Footing With Varying Percentagesof B ...............
Load-Settlement Curve ...............................................................................
Distribution of QpreJQmeas
for 25-mm Settlement:3-m North Footing ...........................
Distribution of QpreJQmcas,
for 25-mm Settlement:3-m South Footing ...........................
Distribution
Distribution
Distribution
Distribution
Distribution
of QpreJQmcas.
for 25-mm Settlement:2.5-m Footing .................................
of Qpre,JQmeas.
for 25-mm Settlement: 1.5-m Footing,, ...............................
of Qprcd./QmeaJ.
for 25-mm Settlement: 1.0-m Footing .................................
of QpreJQmeas.
for 150~mmSettlement:3-m North Footing ...........................
of Qpred./Qmeas.
for 150~mmSettlement:3-m South Footing ............................
Distribution of Qpred./Qmeas.
for 150~mmSettlement:2.5-m Footing ..................................
Distribution of Qpred
/Qmeas.
for 150~mmSettlement: 1.5-m Footing ..................................
27
29
30
32
34
37
38
38
40
40
41
42
43
44
45
46
48
49
50
52
57
57
58
58
59
59
60
60
61
LIST OF FIGURES (continued)
Page
Figure
5.11
6.1
6.2
6.3
Distribution of QpreJQmeas.
for 150~mmSettlement: 1.5-m Footing ...............................
Soil-Footing Model ......................................................................................
The WAK Test ..........................................................................................
Sample of Time Domain Plot ...........................................................................
6.4
6.5
Sample of Mobility Curve: Theorectical vs, Measured..............................................
Typical Load-Settlement Curve .........................................................................
Predicted Stiffness on 1.0-m Footing Before Load Test .............................................
6.6
6.7
6.8
6.9
6.10
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8.10
A.1
A.2
A.3
Predicted Stiffness on 1.5-m Footing Before Load Test .............................................
Predicted Stiffness on 2.5-m Footing Before Load Test .............................................
Predicted Stiffness on 3.0-m North Footing Before Load Test .....................................
Predicted Stiffness on 3.0-m South Footing Before Load Test .....................................
Pressurevs. SettlementCurves.........................................................................
Scale Effect at Large Displacement....................................................................
Triaxial Test/Spread Footing Analogy .................................................................
Pressurevs. Settlement/Width Curves..................................................................
Scale Effect on Modulus of Subgrade Reaction.......................................................
Creep Exponent Curve for 3.0-m North Footing - Qu = 12.50 MN .................................
Lateral Strain vs. Strain ...................................................................................
Comparison of the Horizontal and Vertical Soil Movement..........................................
Schematic of the Volume Change Under Footing ......................................................
PressuremeterCurve (PMT 1, z = 0.6 m). .............................................................
Influence Factor Distribution with Depth ...............................................................
RecommendedInfluence Factor Distribution, and Example of the Determination of the ai
Factors......................................................................................................
FEM Results for Medium Dense Sand................................................................
FEM Results for Dense Sand...... ........................................................................
The Correction Function I? (s/B) .........................................................................
PressuremeterModulus as a Function of Time ...........................................................
Generating the Average PMT Curve for a Footing ......................................................
Predicted Footing Responseby ProposedPMT Method ................................................
Measured Versus PMT Predicted Load SettlementCurves.............................................
SPT-l... .......................................................................................................
SPT-2 ......... .................................................................................................
SPT3 ......... .................................................................................................
vii
61
72
72
73
74
76
78
79
80
81
82
84
a4
85
85
89
91
95
96
98
102
103
103
105
105
107
108
109
110
110
118
119
120
LIST OF FIGURES (continued)
Figure
Page
A.4
SPT-4.......................................................................................................
121
A.5
SPT-5.......................................................................................................
122
A.6
SPT-6.......................................................................................................
123
A.7
Grain Size Distribution .................................................................................
124
A.8
DMT- 1 Test Results w/o Axial Thrust Measurements.............................................
125
A.9
DMT-2 Test Results w/o Axial Thrust Measurements.............................................
126
A.10
DMT-3 Test Results w/ Axial Thrust Measurements...............................................
127
A.11
Axial Thrust Versus Depth for DMT-3 ...............................................................
128
A.12
Stress Strain Curve for 0.6-m Sample...............................................................
129
A.13
Volume Change Curve for 0.6-m Sample............................................................
130
A.14
Stress Strain Curve for 3.0-m Sample................................................................
131
A.15
Volume Change Curve for 3.0-m Sample.........................................................................
132
A.16
Mohr’s Circles From Triaxial Tests...................................................................
133
A.17
Resonant Column Test Results @ 0.0-m ............................................................
134
A.18
Resonant Column Test Results @ 1.6-m............................................................
A.19
Resonant Column Test Results @ 3.3-m ............................................................
135
136
A.20
Resonant Column Test Results @ 6.0-m ............................................................
137
A.21
GraphofBlowCountsNVersusDepthforSPT1,3&4..
.....................................
138
A.22
GraphofBlowCountsNVersusDepthforSPT2,5&6..
......................................
139
A.23
Graph of 4 Versus Depth From Borehole Shear Results..........................................
140
A.24
Cone Penetrometer Test Results for CPT- 1..........................................................
141
A.25
Cone Penetrometer Test Results for CPT-2 ..........................................................
142
A.26
Cone Penetrometer Test Results for CPT-5 ..........................................................
143
A.27
Cone Penetrometer Test Results for CPT-6 ..........................................................
144
A.28
Cone Penetrometer Test Results for CPT-7 ..........................................................
145
A.29
PressuremeterTest Results for PMT- 1. ..............................................................
146
A.30
PressuremeterTest Results for PMT-2., .............................................................
147
A.31
PressuremeterTest Results for PMT-3., .............................................................
148
A.32
PressuremeterTest Results for PMT-4 ...............................................................
149
A.33
Determination of the Creep Exponent for PMT- 1. .................................................
150
A.34
Determination of the Creep Exponent for PMT-2 ..................................................
151
.. .
vu
LIST OF FIGURES (continued)
Figure
B.l
Page
160
B.2
Load Settlement Curve for 1.0-m Footing - Total History ........................................
Load Settlement Curve for 1.0-m Footing - Avg. 30-Minute Curve.....................................
B.3
Load Settlement Curve for 1.5-m Footing - Total History .........................................
162
B.4
Load Settlement Curve for 1.5-m Footing - Avg. 30-Minute Curve.....................................
163
B.5
164
B.6
Load Settlement Curve for 2.5-m Footing - Total History ........................................
Load Settlement Curve for 2.5-m Footing - Avg. 30-Minute Curve.....................................
B.7
Load Settlement Curve for 3.0-m(n) Footing - Total History.. .............................................
166
B.8
Load Settlement Curve for 3.0-m(n) Footing - Avg. 30-Minute Curve.................................
167
B.9
Load Settlement Curve for 3 .O-m(s) Footing - Total History.. ..............................................
168
B-10
Load Settlement Curve for 3.0-m(s) Footing - Avg. 30-Minute Curve ...............................
169
Cl
171
c.2
Individual Creep Exponent Curves for 1.0-m Footing, 0.09 MN - 0.71 MN., ......................
Individual Creep Exponent Curves for 1.0-m Footing, 0.71 MN - 1.25 MN.. .......................
c.3
Individual Creep Exponent Curves for 1.0-m Footing, 1.25 MN - 1.78 MN.. .......................
173
c.4
c.5
Individual Creep Exponent Curves for 1.0-m Footing - 24-Hour Creep Test
174
Individual Creep Exponent Curves for 1.5-m Footing, 0.27 MN - 1.34 MN.. .......................
175
C.6
Individual Creep Exponent Curves for 1.5-m Footing, 1.34 MN - 2.80 MN.. .......................
176
c.7
Individual Creep Exponent Curves for 1.5-m Footing, 3.07 MN - 3.29 MN.. .......................
Individual Creep Exponent Curves for 1.5-m Footing - 24-Hour Creep Test. .....................
177
C.8
c.9
c.10
c.11
c.12
c.13
c.14
161
165
172
178
Individual Creep Exponent Curves for 2.5-m Footing, 0.62 MN - 3.12 MN.. ......................
Individual Creep Exponent Curves for 2.5-m Footing, 4.36 MN - 7.03 MN.. ......................
179
Individual Creep Exponent Curves for 2.5-m Footing - 24-Hour Creep Test.......................
Individual Creep Exponent Curves for 3.0-m(n) Footing, 0.89 MN - 5.34 MN.. .................
181
Individual Creep Exponent Curves for 3.0-m(n) Footing, 6.23 MN - 10.24 MN.. ................
Individual Creep Exponent Curves for 3.0-m(n) Footing - 24-Hour Creep Test..................
183
180
182
184
Cl6
Individual Creep Exponent Curves for 3.0-m(s) Footing, 0.89 MN - 5.34 MN.. .................
Individual Creep Exponent Curves for 3.0-m(s) Footing, 6.23 MN - 8.90 MN ...................
186
c.17
Individual Creep Exponent Curves for 3.0-m(s) Footing - 24-Hour Creep Test
187
C.18
Creep Exponent Curve for 1.0-m Footing - Qu = 1.48 MN ........................................
188
c.19
Creep Exponent Curve for 1.5-m Footing - Qu = 3.38 MN.. .....................................
189
c.20
190
c.21
Creep Exponent Curve for 2.5-m Footing - Qu = 8.50 MN .......................................
Creep Exponent Curve for 3.0-m(n) Footing - Qu = 12.50 MN.. ................................
c.22
Creep Exponent Curve for 3.0-m(s) Footing - Qu = 11.50 MN.. ..........................................
192
c.15
ix
185
191
LIST OF FIGURES (continued)
Figure
Page
D.1
Inclinometer Test - 1.78 MN Failure Load - N-S Direction, 1.0-m Footing ..........................
194
D.2
Inclinometer Test - 1.47 & 3.29 MN Loads - N-S Direction, 1.5-m Footing.. .....................
195
D.3
Inclinometer Test - 1.47 & 3.29 MN Loads - E-W Direction, 1.5-m Footing.. .....................
196
D.4
Inclinometer Test - 3.12~MN Creep Load - N-S Direction, 2.5-m Footing.. .........................
197
D.5
Inclinometer Test - 7.03~MN Failure Load - N-S Direction, 2.5-m Footing.. .......................
198
D.6
Inclinometer Test - 3.12~MN Creep Load - E-W Direction, 2.5-m Footing ..........................
199
D.7
Inclinometer Test - 7.03-MN Failure Load - E-W Direction, 2.5-m Footing.. .....................
200
D.8
Inclinometer Test - 4.45~MN Creep Load - N-S Direction, 3.0-m(n) Footing.. ....................
201
D.9
Inclinometer Test - 8.90~MN Failure Load - N-S Direction, 3.0 m(n) Footing ....................
202
D.10
Inclinometer Test - 4.45~MN Creep Load - E-W Direction, 3.0-m(n) Footing ....................
203
D.ll
D.12
Inclinometer Test - 8.90-MN Failure Load - E-W Direction, 3.0-m(n) Footing.. ..................
Inclinometer Test - 4.45~MN Creep Load - N-S Direction, 3.0-m(s) Footing.. ....................
204
205
D.13
Inclinometer Test - 8.90~MN Failure Load - N-S Direction, 3.0-m(s) Footing.. ...................
206
D.14
Inclinometer Test - 4.45~MN Creep Load - E-W Direction, 3.0-m(s) Footing.. ....................
207
D.15
Inclinometer Test - 8.90~MN Failure Load - E-W Direction, 3.0-m(s) Footing.. ..................
208
E.l
Settlement Versus Depth for 1.0-m Footing With Varying Percentagesof B ......................
210
E.2
Settlement Versus Depth for 1.5-m Footing With Varying Percentagesof B ......................
211
E.3
Settlement Versus Depth for 3.0-m(n) Footing With Varying Percentagesof B.. ................
212
E.4
Settlement Versus Depth for 3.0-m(s) Footing With Varying Percentagesof B.. ................
213
LISTING OF TABLES
Page
Table
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.1
4.2
4.3
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
6.1
Al
A2
A3
General Information Data Files...................................................................
Footing Data Files ..................................................................................
Footing Behavior Data Files.......................................................................
Soil Data Files.......................................................................................
Prediction Method Data Files......................................................................
Case Histories Listed in the Data Base..........................................................
Minimal System Requirements....................................................................
Relationship Between SPT Blow Count and Soil Properties...................................
Data Files Corresponding to Prediction Methods,, ..............................................
As-Built Footing Dimensions......................................................................
Test Dates & People Involved.....................................................................
Dry Hand Augered Samples:Test Results.......................................................
Methods Used........................................................................................
Soil Tests Used.......................................................................................
Prediction Results for Qz5and QlsOin kN .........................................................
...............................................................
Prediction Results for A s and Szf),i&.
Measured Results....................................................................................
Predicted Design Loads .............................................................................
Factors of Safety F = Qf/Qd........................................................................
Settlement Under Design Load, Sd................................................................
Tabulated SettlementPrediction Values .........................................................
Tabulated Bearing Capacity Prediction Values ..................................................
Best Prediction Method Determination...........................................................
.
Summary of WAK Test Results...................................................................
Stepped Blade Test Results.........................................................................
A4
Cross-Hole Test Results............................................................................
Summary of Field Results for SPT Energy Movements........................................
Physical Properties...................................................................................
A5
A6
A7
Moisture Content with Depth for SPT 2 & 3 .....................................................
Moisture Content with Depth for SPT 4 & 5 ......................................................
Moisture Content with Depth for SPT-6 ...........................................................
xi
10
11
11
12
13
13
16
23
24
28
35
36
53
53
54
55
56
64
65
66
68
68
70
77
152
153
154
155
156
157
158
1. SUMMARY
Tasks 1 through 6 describedin section 1.1 below correspondto 6 of the 10 chaptersin
this report which summarizethe work done in eachof the 6 tasks. Five separatereports give
more detail concerning this project. Thesereports are: ((Nasr & Briaud, 1995), (Gibbens&
Briaud, 1995) (Briaud & Gibbens), 1994, (Ballouz, Maxwell & Briaud, 1995) and (Jeanjean&
Briaud, 1994)).
1.1
GOALS
In most casesshallow foundations are lessexpensivethan deep foundations (Briaud,
1992). The FHWA is therefore making efforts to ensurethat spreadfootings are consideredas a
viable alternative for all bridges. Part of this effort is in the form of researchon spreadfootings to
improve the reliability of the design rules thereby increasingthe confidenceof engineersacrossthe
country in this economical solution,
There are approximately 600,000 bridges in the country. If those bridges had to be
replacedtoday by new bridges it would cost approximately $300 billion. Therefore the average
cost of a bridge is $500,000. About 50% of that cost is in the foundation. For such an average
bridge the difference in cost between shallow foundations and deepfoundations is $90,000
(Briaud, 1993).
Each year 6,000 new bridges are built for a yearly national bridge budget of $3 billion.
Approximately 85% of the existing 600,000 bridges in the inventory are over water. This
percentageis probably more like 50% when consideringthe bridgesbuilt in the last few years. If
one assumesthat all 6,000 bridges built yearly are on deepfoundations and if one further assumes
that all bridges that are not over water can be placed on shallow foundations, the numbersabove
indicate a yearly savingto taxpayersof 90,000 x 6000 x 0.5 = $270 million. Even if the savingis
only a fraction of this number, say 100 million, the potential savingis significant. If 5% of the
1
potential saving is investedin research,a budget of $5 million per year is not unreasonableto
make seriousprogresstowards this economic goal.
This researchproject setsthe beginning of this effort and aims at the following goals:
1.
Develop a user friendly computerized addressabledata basefor spreadfootings. Such a
data basewill help identify what load tests havebeen performed, thereby identifying what
load tests are missing and needto be performed. Such a data basewill also help in
evaluating the precision of current designprocedures,modify them if necessaryor develop
new ones. Therefore this data basewould be a designtool as well as a researchtool.
2.
Perform a seriesof large-scalefooting tests on sand. Thesefootings will vary in size from
1 to 3 m, will be squareand embedded0.76 m. The load settlementcurve will be obtained
for eachfooting and the soil will be instrumentedso that the vertical and horizontal
movement of the soil masscan be monitored during the test. Such a seriesof tests will be
used to evaluatethe influence of footing scaleon footing behavior including settlement
and bearing capacity.
3.
Use the results of theselarge-scaletests to evaluatethe existing settlementprediction
methods for footings on sand. A prediction symposiumwill be organized with wide
national and international participation. Prediction packageswill be distributed and
predictions will be collected prior to the load tests. Comparisonswill be made between
predicted and measuredresponsefor all footings.
4.
Perform a seriesof impact tests on the footings. The five footings will be tested with the
Wave Activated stiffnessor WAK test before the load test. An instrumented
sledgehammer,two geophonesand a data acquisition systemwill be used. The data
collected will be used to predict the initial stiffnessof the load settlement curve. Predicted
and measuredstiffnesswill be compared.
5.
Perform the analysisof the load test data. The raw data collected during the five footing
load tests will be reduced and corrected. The data will be analyzedto shedlight on the
scaleeffect, the creep settlementand the soil deformation versusdepth both in vertical and
horizontal directions.
2
6.
Develop, if necessary,a new method to predict the settlementof footings on sand. A new
method may be developedif it is clear from the load test results that a significant
improvement can be achieved.
1.2
RESULTS
1.
A spreadfooting data basehasbeen developed. This data basecomesin the form of an
IBM PC compatible computer program called SHALDB. The program is in two parts: an
organized set of data files follows the DBASE format and a program to manipulatethese
data written in Visual Basic. SHALDB version no. 4 is the version preparedas an
outcome of this project. Version nos. 1 to 3 were also developedat Texas A&M
University from which version no. 4 is available. SHALDB contains at the presenttime 77
casehistories where the behavior of spreadfootings is documented. Some of the case
histories are of the load test type where a complete load settlementcurve was recorded;
some of the casehistories are of the performancemonitoring type where the settlement
versustime was recorded for the given structural load. With the program one can retrieve
the data, inspect it, create a sub data basesatisfying chosencriteria, compare the
measurementswith predictions and so on,
2.
Load tests were performed on five squarefootings ranging in size from I m to 3 m. They
were all embedded0.76 m. The load settlementcurve was recorded for all footings which
were pushedup to 150 mm of penetration. During the tests the deformation of the soil at
depth in the vertical direction was measuredwith telltales at 0.5B, 1B and 2B depths. At
the sametime the deformation of the soil at depth in the horizontal direction was
measuredwith inclinometers at various distancesfrom the footing edge. One of the major
lessonslearned from the instrumentation is that settlementbeamsfor large footing tests
may be unreliable and that the best way to measuresettlementis to place a telltale through
the footing near its center and anchoredat a depth of 4B. A very inexpensivetelltale
systemwas developed.
3.
A very successfulprediction event was organized. A total of 3 1 predictions were received
from 8 different countries, half from consultants,half from academics. The load creating
3
25 mm of settlement425 was under estimatedby 27% on the average. The predictions
were 80% of the time on the safe side. The load creating 150 mm of settlement Ql50 was
underestimatedby 6% on the average. The predictions were 63% of the time on the safe
side. The scaleeffect was not properly predicted and there was a trend towards
overpredicting Ql50 for the larger footings. The most used methods were basedon the
Cone Penetrometer(CPT), StandardPenetration (SPT), and Pressuremeter(PMT) tests in
that order. The averagetrue factor of safety was 5.4. Therefore it appearsthat our
profession knows how to design spreadfootings very safely but could design them more
economically.
4.
An independentset of predictions was performed on the five load tested footings using 12
settlement calculation methods and 6 bearing capacity calculation methods. The best
settlementmethods were the SchmertmannDMT (1986) and the Peck & Bazarra (1967)
although they are somewhaton the unconservativeside. The best conservativemethods
are Briaud (1992) and Burland & Burbidge (1984). The best method for bearing capacity
was the simple 0.2q, method from Briaud (1993). Most other methods were 25 to 42
percent conservative.
5.
WAK tests were performed on the five footings before load testing them. This
sledgehammerimpact test allows one to determination the static stiffnessof the soilfooting assembly. The stiffnesspredicted by the WAK test was compared to the stiffness
measuredat small displacementsin the load tests. The comparison shows that the WAK
test predicted a secantstiffnesswhich intersectsthe load settlementcurve at about 10 mm.
Therefore the WAK test stiffnesscan be usedto predict small settlement,
6.
The medium densesandhad a mean SPT blow count of 20 blows/O.3m, a mean CPT qc
of 7 MPa, a meanPMT limit pressureand modulus of 800 kPa and 8 MPa respectively,a
meanfriction angle of 32’, and a meancrosshole shearwave velocity of 270 m/s. In this
sandthe loads necessaryto reach 150 mm of penetrationwere 1740 kN, 3400 kN, 7100
kN, and 9625 kN for the 1 m, 1.5 m, 2.5 m and 3 m footings respectively. In this sandthe
load necessaryto reach25 mm of penetrationwere 850 kN, 1500 kN, 3600 kN, and 4850
kN for the 1 m, 1.5 m, 2.5 m and 3 m footings respectively,
4
7.
The scaleeffect was studied. It was found that for the five footings tested there was no
scaleeffect; indeed when plotting the load-settlementcurvesas pressurevs. settlement
over width curves, all such curvesvanishto one curve and the scaleeffect disappears.
This is explainedby the uniquenessof the soil stressstrain curve. Sincethe general
bearing capacity equation shows a definite scaleeffect, the use of this equation is not
recommended. The pressurepUcorrespondingto a settlementover width ratio (s/B) equal
to 0.1 can be estimatedas follows:
N
Pu =E
with N in blows/O.3m and pwin MPa
(1)
(2)
pu=y
The allowable pressurepa correspondingto an s/B ratio equal to 0.01 can be estimatedas
follows:
N
Pa =G
with N in blows/O.3m and pa in MPa
4c
Pa=12
(3)
(4)
Another finding related to scalewas that a sanddeposit which is apparently very
heterogeneousat the scaleof an in situ test (say maybe 50 mm) may be quite
homogeneousat the scaleof a spreadfooting (say maybe3000 mm).
8.
The creep settlementwas studied. It was found that the power law model proposed by
Briaud and Garland (1985) fit the data very well:
where st and stoare the settlementsof the footing after a time t and to respectively. The
exponent n was found to vary from 0.01 to 0.05. For n = 0.03 the settlementat 50 years
5
would be 1.67 times larger than the settlementat 1 min. Therefore the creep settlement in
sandcannot be neglectedyet is not of dramatic proportion. The value of n for the
footings increasedwith the load level and decreasedwith unload-reload cycles and was,
on the average,equal to 2 times the n value obtained from the pressuremetertest:
n footing = 2n pressuremeter
9.
(6)
The soil movement at depth in the vertical direction was studied. It was found that on the
average36% of the top settlementoccurs between 0 and 0.5B below the footing, 42%
between 0.5B and lB, 19% between 1B and 2B, and 3% below 2B. Therefore 2B seems
to be a reasonabledepth of influence for such footings and the averagestrain below the
footing is s/2B. The strain vs. depth profile obtained from the telltales shows a natural
increasein strain with depth except close to the bottom of the footing where the strain
decreasesdue to the lateral confinementbrought about by the roughnessof the footing.
10.
The soil movement at depth in the horizontal direction was studied. It was found that the
general shapeof the inclinometer curvesis a lateral bulging of the soil with a maximum at
a depth averaging0.73B and a bottom at a depth averaging2.33B. The maximum
horizontal movement is of the order of 15% of the footing settlementand the horizontal
zone of influence extendsto about 1.8B beyond the edge on each side of the footing.
Approximate calculations indicate that the soil massunder the footing does not dilate but
instead compressesfor this medium densesand.
11.
A new method for predicting the behavior of spreadfootings on sandwas developedusing
pressuremetertesting. It is drastically different from existing methods in that it gives a
prediction of the complete load settlementcurve. Becausethe deformation pattern under
the footing resemblesthe expansionof a cavity, the pressuremetertest was chosen. The
pressuremetercurve is simply transformed point by point to obtain the footing curve as
follows:
Pfooting = r ( Ppressuremeter1
S
-=-
ARC
B
4.2R,
6
is the pressuremeterpressure,r is the
where Pfootilig is the footing pressure,pnresstrmrneter
transfer function recommendedon the basisof the load test data and finite element
analysis,s is the footing settlementcorrespondingto pfootirlg,B is the footing width and
AR&
is the relative increasein cavity radius on the pressuremetercurve at a pressure
equal to Ppressurcmeter.
7
2. INTRODUCTION
This report is a summaryreport for the project. Its purpose is to summarizethe project,
the tests done, the results obtained, the analysisperformed and the conclusionsreached. It will
allow the reader to go through about 100 pagesand learn the essenceof the project in a short
time. If the reader requires more detailed information he or she can refer to the following detailed
reports: ((Nasr & Briaud, 1995) (Gibbens& Briaud, 1995), (Briaud & Gibbens, 1994) (Ballouz,
Maxwell & Briaud, 1995) and (Jeanjean& Briaud, 1994)).
In most casesshallow foundations are lessexpensivethan deep foundations (Briaud,
1992). The FHWA is therefore making efforts to ensurethat spreadfootings are consideredas a
viable alternative for all bridges. Part of this effort is in the form of researchon spreadfootings to
improve the reliability of the design rules thereby increasingthe confidenceof engineersacrossthe
country in this economical solution.
There are approximately 600,000 bridges in the country. If those bridges had to be
replacedtoday by new bridges it would cost approximately $300 billion. Therefore the average
cost of a bridge is $500,000. About 50% of that cost is in the foundation. For such an average
bridge the difference in cost between shallow foundations and deep foundations is $90,000
(Briaud, 1993).
Each year 6000 new bridges are built for a yearly national bridge budget of $3 billion.
Approximately 85% of the existing 600,000 bridges in the inventory are over water. This
percentageis probably more like 50% when consideringthe bridges built in the last few years. If
one assumesthat all 6000 bridges built yearly are on deepfoundations and if one further assumes
that all bridges that are not over water can be placed on shallow foundations, the numbersabove
indicate a yearly savingto taxpayersof 90,000 x 6000 x 0.5 = $270 million. Even if the saving is
only a fraction of this number, say 100 million, the potential savingis significant. If 5% of the
potential savingis investedin research,a budget of $5 million per year is not unreasonableto
make seriousprogresstowards this economic goal.
8
This researchproject setsthe beginning of this effort and aims at the following goals:
1.
Develop a user friendly computerized addressabledata basefor spreadfootings. Such a
data basewill help identify what load tests havebeen performed, thereby identifying what
load tests are missing and needto be performed. Such a data basewill also help in
evaluating the precision of current design procedures,mod@ them if necessaryor develop
new ones. Therefore this data basewould be a designtool as well as a researchtool.
2.
Perform a seriesof large-scalefooting tests on sand. Thesefootings will vary in size from
1 to 3 m, will be squareand embedded0.76 m. The load settlementcurve will .beobtained
for eachfooting and the soil will be instrumentedso that the vertical and horizontal
movement of the soil masscan be monitored during the test. Such a seriesof tests will be
used to evaluatethe influence of footing scaleon footing behavior including settlement
and bearing capacity.
3.
Use the results of theselarge-scaletests to evaluatethe existing settlementprediction
methods for footings on sand. A prediction symposiumwill be organizedwith wide
national and international participation, Prediction packageswill be distributed and
predictions will be collected prior to the load tests. Comparisonswill be madebetween
predicted and measuredresponsefor all footings,
4.
Perform a seriesof impact tests on the footings. The 5 footings will be tested with the
Wave Activated stiffnessor WAK test before the load test. An instrumented
sledgehammer,two geophonesand a data acquisition systemwill be used. The data
collected will be used to predict the initial stiffnessof the load settlement curve. Predicted
and measuredstiffnesswill be compared.
5.
Perform the analysisof the load test data, The raw data collected during the 5 footing
load tests will be reduced and corrected. The data will be analyzedto shedlight on the
scaleeffect, the creep settlementand the soil deformation versusdepth both in vertical and
horizontal directions.
6.
Develop, if necessary,a new method to predict the settlementof footings on sand. A new
method may be developedif it is clear from the load test results that a significant
improvement can be achieved.
3. SHALDB:
3.1
DATA BASE OF SPREAD FOOTINGS
THE DATA BASE FILES
This part of the project is detailed in Nasr and Briaud, 1995.
The shallow foundation data baseis divided into two main parts; the data baseprogram
and the data basefiles,
The data baseprogram enablesthe user to easily accessand manipulatethe data files that
describethe many casehistories stored in the data base.
The data basefiles are a seriesof data files, written, updated and modified by the program.
Thesefiles are written in the DBASE IV file format and thus havethe tile format *.DBF. These
files can be grouped into four generaltypes; general information, footing data, footing behavior
and soil data and settlementpredictions.
3.1.1
General Information
General information files contain data of general interest. This consistsof information as
to the location of the casehistory, the referencesin which the casehistory is mentioned, the
personsconnectedwith the case,as well as a rating of the data quality. The general information
files are listed in Table 3.1.
Table 3.1: GeneralInformation Data Files
FILE NAME
CONTACTS.DBF
FOOTLIST.DBF
GENINFl .DBF
RATING.DBF
TYPE OF DATA STORED IN THE FILE
Personfamiliar with the data and person who entered the data
List of footings in the data base
Footing location and references
Data quality ratings on a scaleof 1 (mediocre) to 10 (excellent)
10
The rating data file containsratings of the data on footing geometry, soil properties and
in-situ tests, loads applied, as well as footing movement. Casehistories are rated on a scaleof
zero to 10, zero being the rate of a poorly documentedcase,and 10 being that of a very well
documentedcase. Since the rating method has not been completely establishedyet, the rating file
is empty and all the valuesin that file are set to zero.
3.1.2
Footing Data
The footing data files are files that contain information on footing size, shape,and basic
layout. The footing data files are displayedin Table 3.2.
Table 3.2: Footing Data Files
FILE NAME
FOTDATl.DBF
INDDAT.DBF
3.1.3
TYPE OF DATA STORED IN THE FILE
Footing dimensions
Index table listing which type of data has beenupdatedfor which footing
Footing Behavior
Information about the loads applied on the foundation as well as about the load-settlement
behavior of the foundation are containedin the footing behavior files. Thesefiles on footing
behavior are listed in Table 3.3,
Table 3.3: Footing Behavior Data Files
FILE NAME
LOADDATA.DBF
SETLDATA.DBF
3.1.4
TYPE OF DATA STORED IN THE FILE
Type and magnitude of the load applied on that footing
Load settlementtime data
Soil Data
The soil data tiles contain information about the soil layers, the physical soil properties, as
well as in-situ test data. The files on soil properties data are shown in Table 3.4.
11
Table 3.4: Soil Data Files
FILE NAME
LAYERDAT.DBF
LAYERDT.DBF
DEFRMDAT.DBF
DEFRMDT.DBF
SHEARDAT.DBF
SHEARDT.DBF
PROPDATA.DBF
1 PROPDAT.DBF
SPTDATA.DBF
SPTDAT.DBF
CPTDATA.DBF
CPTDAT.DBF
PMTDATA.DBF
PMTDAT
T)RF
[ DMTDAT.PMT
TYPE OF DATA STORED IN THE FILE
Soil layer data
Soil deformation data
Shear strength data
1
I
Standard Penetration Test data
Cone PenetrometerTest data
Prewmmetcr
Ted
dntn
Dilatometer Test data
As shown in Table 3.4, there are two different data basefiles for eachtype of soil data file.
The first tile containsthe data correspondingto soil profiles. For example,the file
SPTDATA.DBF, contains SPT number of blows per foot versusdepth.
The secondfile contains averagesand notes. The file SPTDAT.DBF contains the values
for averagenumber of blows per foot and standarddeviation, as well as hammertype and notes
on the data itself
In the particular caseof soil properties data, the third file, PROP-CAL.DBF, contains
information about automatic calculationsthat are sometimescarried out by the computer. More
information about these automatic calculationsis found in section 3.2.5.1.
3.1.5
Settlement Predictions
The settlementprediction files contain the predicted settlementsfor all the cases. These
settlementsare calculatedwhen the correspondingsoil data information is input or updated. A
list of thesefiles and the referencefor eachof the methods is shown in Table 3.5.
It should be noted here that only methodsfor settlementprediction on sandthat are based
on in-situ testing techniqueswere programmedinto SHALDB.
12
Table 3.5: Prediction Methods Data Files
FILE NAME
PREDICTION METHOD CORRESPONDINGTO THE FILE
SPT kU?THODS
CPT SHM.DBF
DhYT METHODS
Schmertmann,Hartman and Brown (1978) and Schmertmann(1970)
I
DMT SHM.DBF
Schmertmann (1986)
PMTMETHODS
PMT BRICXDBF
Briaad (I 9921
PMT MNRD.DBF 1 Menard and Rousseau(1962)
3.1.6
Case Histories Listed in the Data Base
As of September 1995, the time this report was completed, the data base contained 77
casehistories. These casehistories and their referenceare listed in Table 3.6.
Table 3.6: CaseHistories Listed in the Data Base
Nb.
FOOTING NAME
M5000, North Avenue Sideline Over VT127, E Abut. #l
1
2
M5000, North Avenue Sideline Over VT127, E Abut. #2
3
#131-132-l 1, I-691 Under Dickerman Road, S Abut. #l
4
#131-132-l 1, I-691 Under Dickerman Road, N Abut #2
5
#131-132-l 1, I-691 Under Dickerman Road Center Pier
6
I#931, Branch Avenue, NE Corridor, W Abut
7
#93 1, Branch Avenue, NE Corridor, E Abut
8
#93 1, Branch Avenue, NE Corridor, Pier 1 North
13
REFERENCE
Gifford et al. (1989)
Gifford and Perkins (1989)
Gifford et al. (1989)
Gifford and Perkins (1989)
Gifford et al. (1989)
Gifford and Perkins (1989)
Gifford et al. (1989)
Gifford and Perkins ( 1989)
Gifford et al. (198’9)
Gifford and Perkins (1989)
(Gifford et al. (1989)
Gifford and Perkins (1989)
Gifford et al. (1989)
Gifford and Perkins (1989)
Gifford et al. (1989)
1Gifford and Perkins ( 1989)
Table 3.6: CaseHistories Listed in the Data Base (continued)
9
10
11
12
13
#93 1, Branch Avenue, NE Corridor, Pier 1 South
Gifford et al. (1989)
Gifford and Perkins (1989)
#93 1, Branch Avenue, NE Corridor, Pier 2 North
Gifford et al. (1989)
Gifford and Perkins (1989)
#93 1, Branch Avenue, NE Corridor, Pier 2 South
Gifford et al. (1989)
Gifford and Perkins (1989)
#931, Branch Avenue, NE Corridor, Pier 3 North
Gifford et al. (1989)
Gifford and Perkins (1989)
#93 1, Branch Avenue, NE Corridor, Pier 3 North
Gifford et al. (1989)
Gifford and Perkins (I 989)
Gifford et al. (1989)
RelocatedGersoni Road- Route 28 Route 7, S Abut.
IGifford and Perkins (1989) I
Gifford et al. (1989)
RelocatedGersoni Road- Route 28 Route 7, N Abut.
IGifford and Perkins ( 1989) I
Gifford et al. (1989)
Route 146 Southbound Over Reloc. Lackey Dam Road: N Abut.
Gifford and Perkins (1989)
Gifford et al. (1989)
Route 146 Southbound over Reloc. Lackey Dam Road
Gifford and Perkins (1989)
VM Route 111 Over the Middle Branch - Willams River -- E Abut. Gifford et al. (1989)
Gifford and Perkins (1989)
VM Route 111 Over the Middle Branch - Willams River - W Abut. Gifford et al. (1989)
Gifford and Perkins (1989)
Gifford et al. (1989)
Bridge # 76-88-7 I-86 - E Abut.
Gifford and Perkins (1989)
I-86 & CD Roadwayunder toll and Turnpike - W Abut.
Gifford et al. (1989)
Gifford and Perkins (1989)
1-86 & CD Roadway under toll and Turnpike - E Abut,
Gifford et al. (1989)
Gifford and Perkins (1989)
CD-WB Roadway& Ramp 1 Over Buckland St. (I-86) - W Abut.
Gifford et al. (1989)
Gifford and Perkins (1989)
CD-WB Roadway& Ramp 1 Over Buckland St. (I-86) - E Abut.
Gifford et al. (1989)
Gifford and Perkins (1989)
US501 Bypassover US50l,-#4, BENT #3
Baus, R.L., (1991)
SC 38 Twin overpassesover US301, #l, BENT #3, EBL
Baus, R.L., (1991)
SC 38 Twin overpassesover US301, #3, BENT #3, EBL
Baus, R.L., (1991)
SC 38 Twin overnassesover US301. #l. BENT #3. WBL
Baus. R.L.. (1991)
Baus, R.L., (1991)
SC 38 Twin overpassesover US301, #l, BENT #4. EBL
SC 38. Twin overpassesover US301, #3. BENT #3, WBL
Baus, R.L., (1991)
CS 38 Twin overpassesover US301, #3, BENT #4, EBL
Baus, R.L., (1991)
US501 Bypassover US501,-#l, BENT #3
Baus, R.L., (1991)
Alabama DOT. I-359
Lockett. L.. (1981)
IAlabama DOT. I-359-#l
ILockett. L.. (1981)
I
Texas A&M University, Riverside Campus, 1.Omx 1.Om
Briaud and Gibbens (1994)
Texas A&M University, Riverside Campus, 1.5m x 1.5m
Briaud and Gibbens (1994)
Texas A&M University, Riverside Campus,3.0m x 3.0m. North
Briaud and Gibbens (1994)
Texas A&M University, Riverside Campus,3.0m x 3.0m, South
Briaud and Gibbens (1994)
Texas A&M University, Riverside Campus,2.5m x 2.5m
Briaud and Gibbens (1994)
University of Florida,-June 1992
Skyles. D.L., (1992)
I I
I I
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
134
35
36
37
38
39
40
14
Table 3.6: CaseHistories Listed in the Data Base (continued)
41
42
144
145
146
147
148
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
IUniversity of Florida, July 1992
IUniversitv of Florida. Sentember990
IUniversitv of Florida. Mav 1991
ISwedish Geotech(a Kolbvttemon. Slab 2.30 x 2.50 m
ISwedish Geotechti Fittia. Slab 2.30 x 2.50 m
ISwedish GeotechIn?Kolbvttemon. Slab 1.10 x 1.30 m
ISwedish Geotech(cj!Fittia. Slab 1.10 x 1.30 m
ISwedish Geotech(i-i!Kolbvttemon. Slab 1.60 x 1.80 m
Swedish Geotech@,Fittja, Slab 1.60 x 1.80 m
GeotechnicaLoad Tests, (AF6)
GeotechnicaLoad Tests, (AF7)
GeotechnicaLoad Tests. fAF81
GeotechnicaLoad Tests, (CG6)
GeotechnicaLoad Tests, (TM 1)
GeotechnicaLoad Tests, (TM2)
GeotechnicaLoad Tests, (TM3)
GeotechnicaLoad Tests, (CA 1)
GeotechnicaLoad Tests, (A 5)
GeotechnicaLoad Tests. (A 6)
GeotechnicaLoad Tests, (C 3)
GeotechnicaLoad Tests, (C 4)
GeotechnicaLoad Tests. (AF 1)
GeotechnicaLoad Tests, (AF 4)
GeotechnicaLoad Tests. (CG 4)
ISkyles, D.L., (1992)
ISkvles. D.L.. (1992)
ISkvles. D.L.. (1992)
IBergdahl et al. (1985)
IBeredahl et al. (1985)
IBeradahl et al. (1985)
IBerndahl et al. (1985)
IBergdahl et al. (1985)
Bergdahl et al. (1985)
Garga and Quin (1974)
Garga and Quin (1974)
Garrzraand &in I19741
Garga and Quin ( 1974)
Garga and Quin (1974)
Garga and Quin (1974)
Garga and Quin (1974)
Garga and Quin (1974)
Garga and Quin (1974)
Garua and Ouin (1974)
Garga and Quin (1974)
Garga and Quin ( 1974)
Garga and Quin (1974)
Garga and Quin (1974)
Garga and Ouin ( 1974)
71
72
73
74
175
176
177
IFHWA @ Fairbank - Series95 #2295c
IFHWA @.Fairbank - Series95 #15495RA
IFHWA cii, Fairbank Series95 #2395c
IFHWA (ir! Fairbank - series85 #3 185
IFHWA (0).Fairbank - series 85 #2285
IFHWA a, Fairbank - series85 #1185
IFHWA iti, Fairbank - series 85 #15185
IDiMillio
IDiMillio
IDiMillio
IDiMillio
IDiMillio
IDiMillio
IDiMillio
3.2
THE DATA BASE PROGRAM
143
(1994)
(1994)
(1994)
(1994)
( 1994)
( 1994)
(1994)
I
I
I
I
I
I
I
I
I
The Shallow Foundation data base,SHALDB, is made of two main parts, a seriesof data
basefiles and a data baseprogram.
15
The program, SHALDB, is a front-end interface that accessesand manipulatesthe data
written in the data basefiles. It is divided into three main sections:maintenance,inquiries and
search.
The maintenancesection consistsof two parts: footing data addition and footing data
modification. In order to distinguish this section from the others, the main background color of
the windows in this section is set to white. A more elaborateexplanation of thesetwo options can
be found in section 3.2.3.
The inquiries section is made of two parts: parameterbasedsearchand footing data
viewing. The background color for the parameterbasedsearchis light gray, while that for the
footing viewing is light blue, A more detailed explanation on the inquiries and footing viewing
options can be found in section 3.2.4.
The data analysissection is made of only one option, which background color is dark blue.
Details on this part of the program can be found in section 3.2.5.
SHALDB writes the data files in the DBASE IV format, and savesthem in the
C:\SHALDB directory on the hard drive.
3.2.1
System Requirements
The systemon which the program can be installed and used should meet the minimum
requirementslisted in Table 3.7 below:
Table 3.7: Minimal SystemRequirements
ITEM
SystemDescription
Operating System
Memorv
3.2.2
REQUIREMENTS
Intel Compatible 386/33
Windows 3.1 running over DOS 5.0 or higher
4 MB of hard disk soace
Installation
SHALDB comes as an easy to install, two diskettes package. In order to install the
program, one should follow the procedure describedbelow:
1.
Run Windows,
16
2.
3.
4.
5.
6.
Insert disk 1 in drive A,
Select the Windows “PROGRAM MANAGER” icon by double clicking
on it, in casethe program manageris minimized,
From the “PROGRAM MANAGER” menu, select “FILE”,
Under “FILE”, selectthe option marked “RUN”,
A window appearstitled “RUN”. In the box labeled “Command Line”,
type the following:
a:\setup.exe
7.
The setup utility is then launched. A window titled “SHALDB SETUP”
will then appear. In the box labeled “INSTALL TO”, the name of the
addressdirectory is written,
The default directory is “C:\SHALDB”. The user should not attempt to changethe
default. Even though the installation would then run successfully,the program will not. Queries
and file addressingroutines in the program have all beenprogrammedto look for the files in that
exact directory. If thesefiles have all been installed somewhereelse,the program will not find
them. It could then crash,get stuck in an infinite loop, or even display wrong and meaningless
values.
3.2.3
The Maintenance
Section
The data basemaintenancesection is the first of the three sectionsin the program. This
section enablesthe user to enter new casehistories in the data base,as well as accessand modify
existing data.
As with every other section in the program, it is color coded to give the user a feel that
differentiates it from other sections. The pop-up windows in this particular section will appear
with a white background.
17
3.2.3,l Adding a New CaseHistorv
In order to add a new casehistory to the data base,one must selectthe option marked
“ADD A FOOTING” from the main menu. A window titled “FOOTING LOCATION AND
LITERATURE REFERENCES” will appear.
The program, after counting the casesstored in the data base,automatically assignsa
footing number to the casehistory, and displaysit on every pop-up window. The footing number
is written next to the title of the window
In this particular section, the user is prompted to enter general information on the case
history: the title of the case,its location, and the referencesfrom which all data has been obtained.
The user is limited to 4 references. The user can choosefrom a list of countries, or type in and
enter any of those that are not on display.
Once the button marked “ADD THIS FOOTING” is selected,the program accessesand
updatesthe files GENINFl .DBF and FOOTLIST.DBF.
A window titled “DATABASE UPDATE” is then displayedwith the new footing number.
Buttons that correspondto data that hasjust beenupdated are marked with a check next to them
to show that the correspondingdata has been entered.
Since a caserecord would be meaninglesswith no footing data, the program disablesall
the other buttons until such information hasbeen entered. The two buttons labeled “CONTACT
PERSONS” and “DATA RATING” would be enabledbecausethe data tiles that they correspond
to are not as essential.
The procedure to enter the remaining data is essentiallythe sameas that for updating
information and is destiribedin the next section.
3.2.3.2 Modifiing an Existing CaseHistorv
In order to modify an existing casehistory, one must selectthe option marked “MODIFY
AND DELETE FOOTINGS” from the main menu. A window will then appearentitled “LIST
OF FOOTINGS FOR DATA MODIFICATION” which will list all footings in the data base.
One would then have to double-click on the number of the footing that has to be modified.
When this is done, the window describedin the previous section would appear. The user can then
selectthe type of data that needsto be modified or updated.
18
The modification examplethat will be discussedhere will be SPT data modification. Once
the button marked “STANDARD PENETRATION TEST” is selected,a pop-up window titled
“STANDARD PENETRATION TEST DATA” will then appear.
It is possibleto view and enter data in units other than the SI units. This option is
explained in detail in section 3.2.5.2.
This window lists all SPT data for one particular borehole, and shows buttons marked
“UPDATE”, “PRINT”, “VIEW NOTE”, and ” QUIT ‘I, as well as a help button.
When the button marked “UPDATE” is selected,the user will be first prompted to
confirm the update. When this is done, the program will remove the points that have been marked
for deletion, and calculate averagesand standarddeviations.
The data is marked or unmarkedfor deletion by double clicking on the gray squarenext to
the row of values considered. The sign displayedwill then changefrom a I’+” (unmarked for
deletion) to a “-” (marked for deletion), When the update button is selected,the program will
delete the data point marked with a “-” sign, and will not display it again.
Calculation of averagesis explainedin section 3.2.5.3.
In somewindows, the button marked “PLOT” enablesthe user to view a plot of the data.
In the caseof the SPT data, the plot will show the SPT blowcount versusdepth.
These plot windows have a “PRINT” button that enablesthe user to get a scaledprintout
of the plot displayed.
When the “PRINT” button is selected,the program will print a simple report of the data
displayed.
The “VIEW NOTE” button allows the user to view or modify a note that contains
information about the data displayed. When this button is clicked, its title changesto “HIDE
NOTE”, and a small window marked “NOTE” is then displayed. The user can then read or write
observationson the data. In the presentversion, the length of the note is limited to 256
charactersbecauseof the DBASE IV format.
When the “QUIT” button is clicked, the window disappearsand the data update window
reappears. For SPT, CPT, PMT and DMT data the program would run a settlementprediction
routine that calculatesthe predicted settlement. This routine runs when the data hasbeen
previously updated.
19
Finally, all data update windows have a help button that consistsof a red question mark in
a yellow square. By double-clicking on the help button, one would be able to view a help window
that would explain the featuresof that particular data update section.
In addition to that help button, somedata update windows where symbolic values are
shown have an additional help routine. One hasto move the mouse pointer over the symbol that
is not understood, then pressthe 1eAmousebutton. A statementgiving the name or significance
of that symbol is then displayed. This statementstaysas long as the mouse pointer is over the
symbol.
3.2.4
The Inquiries
Section
The secondsection of the program is the inquiries section, in which it is possibleto either
run a parameterbasedsearch,or view the data of a chosenfooting.
3.2.4.1 The ParameterBased Search
The parameterbasedsearchallows searchesof groups of casehistories that sharea similar
set of parametersto be performed. This option will get more and more useful as the data base
grows larger.
In order to run a parameterbasedsearch,one must selectthe option “PARAMETER
BASED SEARCH” from the main menu. The,program will then accessthe data base,reading the
footing namesand numbersand counting them. A window titled “PARAMETER BASED
SEARCH” will then appear.
It is then possibleto select or deselectparametersby viewing the list of parametersin the
searchpull-down menu. Once a parameteris selected,the program will prompt the user to set the
maximum and minimum valuesthat this parametercan have. A window will appearin which one
can enter the parameterboundariesand decide on the course of action to follow. One can
proceed with the searchor abort, or remove previously selectedparametersfrom the list of
parameters.
Once all chosenparametershavebeen set and selected,the searchcan be initiated by
selecting “SEARCH” from the pull-down menu. The program will then go through all the relevant
20
files and compare recorded data to the parameters,by choosing only the casesthat meet the
searchrequirements.
When the program is done browsing through the files, a new window will appearthat
shows a list of the footings that the program found to meet the searchrequirements. This window
is entitled “SEARCH BY PARAMETER RESULTS”
3.2.4.2 Viewing a Footing
This option works in the sameway as the data update option, except that the user is not
allowed to perform any data update or unit changeswhile browsing, nor is he confined to
selectingit from the main menu,
The option to view data from a footing is availableto the user at different stagesof the
program. One can selectthe option to view the data of a particular footing not only from the
main menu, but also from within either a parameterbasedsearchoption, or a data analysis.
In order to view data from the main menu, one must selectthe “VIEW A FOOTING”
option from under the “INQUIRIES” section,
3.2.5
The Data Analysis Section
The Data Analysis Section is divided in three parts; Background Calculations, Settlement
Prediction Calculations, and the Data Analysis section itself
3.2.5.1 Background Calculations
Background calculations are performed automatically by the program every time the units
are changedor the data is updated.
3.2.5.2 Unit Conversions
When a data entry window is open, the valuesin the data baseare first stored in an array,
then displayed in tables. The units can be changedby double clicking on the legend at the top of a
table. Only units whose legend are in colors other than black can be changed.
Units of variablesdisplayedin black will not change,and modifying them will have no
effect on the content of the data base. They correspondto valuescalculatedby the program and
21
displayed to provide the user additional information The units of the data stored in the files are
always SystemInternational Metric (SI).
When the unit of a variable is modified, all valuescorrespondingto that particular variable
are converted. The buttons marked “UPDATE” and “QUIT” are disabled. Thesebuttons will be
re-enabledwhen all the units of all the variablesin that particular window are set back in SI. This
will ensurethat no data savedwill be in units other than SI.
3.2.5.3 Averagesand StandardDeviation
Weighted averagesand standarddeviations are another type of background calculations
performed by the program.
The weighted averageof a variable is calculatedwith respectto depth, and for the whole
depth of testing, as well as for depth valuesequal to one, two, and three times the width of the
footing under its base.
The standarddeviation is also automatically calculatedonce the data is updated, not based
on a weighted average,but on a straight average.
Since these depths are measuredstarting from the bottom of the footing, the computer
adjusts automatically for the difference in borehole elevation, footing embedment,footing
thickness, and ground surfaceelevation.
Averagesare computed automatically once the “UPDATE” button is selected. Since an
update directly affects the data stored in the data base,it is final. After the update has been
selected,there is no going back. All the data listed in that window is stored in an array. Then,
upon quitting the data entry window, a query is launchedthat deletesall old data in the
correspondingfiles. The new data in the array is then copied into the file.
Becauseof that, the user will be prompted to confirm this in casethe “UPDATE” button
has been selectedby mistake.
3.2.5.4 Unit Weight and OverburdenPressure
Once “STANDARD PENETRATION TEST” hasbeen enteredand updated, the program
checksto seeif any soil property data such as total unit weight and relative density havebeen
enteredby verifying their overall averagevalue in the soil physical properties file named
22
PROPDAT.DBF. In casetheseaveragesare equal to zero, which could meanthat none of these
data have been entered,the program then calculatesthe valuesof total unit weight, YT in (kN/mj),
relative density, DR in (Oh),and angle of internal friction, O
The calculations for relative density are basedon a relationship derived, for saturated
sands,by Gibbs and Holtz (1957) and those for unit weight are basedon data published by
Bowles (1988). Thesevalues are shown in Table 3.8.
Table 3.8: Relationship Between SPT Blow Count and Soil Properties
DESCRIPTION
SPT Blowcount (Blow&I)
Relative Density (%)
Total Unit Weight (kN/m”)
Very Loose
0
11
Loose
4
0.15
16
Medium
10
0.35
18
Dense
30
0.65
20
Very Dense
50
0.85
22
The values expressedin Table 3.8 are only approximate. However, prediction methods
often necessitatedetermination of the overburdenpressureat a certain depth and sometimes
require knowledge of the relative density of the sand. Furthermore, few casehistories are found
with results from extensivelaboratory testing.
It was therefore necessaryto “commit” suchapproximations in order for the program to
run smoothly and for the data entry to be facilitated. The program warns the user of the fact that
an approximation was done, by writing a note that can be viewed once the soil physical properties
window is accessed.The user can, upon reading that note, mod@ the data displayed in the Soil
Physical and Engineering Properties window.
That note can be viewed by clicking on the button labeled “VIEW A NOTE” in the Soil
Physical and Engineering Properties window.
3.2.6
Settlement Prediction Methods
Of the many methods availablefor predicting the settlementof footings on sand, 13 have
been selectedto be incorporated in the program. They are basedon four different in-situ tests;
23
StandardPenetration (SPT), Cone Penetrometer(CPT), Dilatometer (DMT), and Pressuremeter
(PMT).
The SPT basedmethods consideredare the ones developedby Anagnostopoulos et al.
(1982), Burland & Burbridge (1984), Meyerhof (1965), Parry (197 l), Peck & Bazarraa (1967),
Schultze & Sherif (1973) and Terzaghi & Peck (1967). The CPT Based methods were derived
by Amar et al. (1989) Meyerhof (1965) and Schmertmannet al. (1970, 1978). The PMT based
methods consideredwere developedby Briaud (1992) and Menard & Rousseau(1962). Finally,
the DMT basedmethod programmedis the one developedby Schmertmann(1986).
Once relevant data hasbeen updated, the program runs the correspondingprediction
routines. Table 3.9 shows this relationship,
Table 3.9: Data Files Correspondingto Prediction Methods
DATA TYPE
Footing Dimensions
Load-Settlement
Soil Properties
Standard Penetration Test
Cone PenetrometerTest
Dilatometer Test
PressuremeterTest
METHOD TYPE
All Methods
All Methods
All Methods
SPT Methods
CPT Methods
DMT Methods
PMT Methods
When the routine that computessettlementpredictions is started, the program will first
accessthe in-situ test file in order to read the relevant test data and the borehole elevation. It will
then accessthe footing geometry file in order to read the footing width, length, embedmentdepth
and natural ground elevation. Then the load settlementfile is accessed,and data from the
pressureversusnormalized settlement(ratio of settlementover footing width) curve is read.
The program will then compute a predicted normalized settlementvalue for each of the
recorded pressurepoints on the pressureversusnormalized settlementcurve. The resulting
predicted pressureversusnormalized settlementcurve is then stored in a data file that
correspondsto the prediction method, For most methods,this curve will be a straight line.
24
Once the program has carried out the calculations,it is possibleto view the predicted
settlement curves, In order to do that, one must selectthe load-settlementdata window, and
selectthe load-settlementoption by clicking on the button marked “LOAD-SETTLEMENT
PLOT” A window titled “LOAD-SETTLEMENT PLOT” will appear.
On the load-settlement plot screen,the pressureversusnormalized settlementcurve will
be displayed. By selectingthe button marked “METHODS”, a window titled “SETTLEMENT
PREDICTION METHODS” will appearwith a list of methodsthat can be plotted. The user has
to selectthe adequatemethod or methods, and then selectthe button marked “DONE”, in order
for the predicted curvesto be plotted.
3.2.7
Data Analysis
The program enablesthe user to run simple data analysis, In order to start a data analysis,
the user has to selectthe option “DATA ANALYSIS” from the main menu,
The user has then the option of viewing either a simple x-y plot, or a frequency
distribution plot, by selectingthe correspondingplot type from the “Plot Type” option from the
menu of the window displayed.
After the plot type hasbeen selectedfrom the “Plot Type” option, the user hasto select
“Start Data Analysis” from the “Start Analysis” option in order to launch the plot utility. The x
axis variable is chosen,then the y axis variable is chosenand the x-y plot is viewed.
25
4. LOAD TESTING
4.1
OF FIVE LARGE-SCALE
FOOTINGS
ON SAND
LOAD TEST SETUP
This part of the project is detailed in Gibbensand Briaud, 1995.
Five spreadfootings and five reaction shafts(Figure 4.1) were built at the sand site on the
Texas A&M University National GeotechnicalExperimentation Site (NGES). Two 3 by 3 by 1.2m footings, one 2.5 by 2.5 by 1.2-m footing, one 1.5 by 1.5 by 1.2-m footing and one 1 by 1 by
1.2-m footings were built along with four 0.91-m diameter, 21.3-m long drilled shaftswith 2.7-m
- 60” under-reamedbells and one 0.91-m diameter, 5-m long straight drilled shaft. The exact asbuilt dimensionsare shown in Table 4.1.
The four drilled and belled shaftswere founded at depths ranging from 19.6 to 20.6 m as
determined in the field during shaft construction. The straight shaft was founded at a depth of 5
m. The footings and reaction shaftswere spacedon 8.53-m centersexcept for the straight shaft
which was spacedas shown on Figure 4.1. Each shaft, except the straight shaft, was designed
and built to minimize any effect on the surrounding soils that a column of high strength concrete
might have. Figure 4.2 shows the designof the shaftswhich used a mix of sandand cement,
designedto approximate the strength characteristicsof the surrounding sand,to fill the void above
the concrete shaR. Figure 4.2 also shows an overall profile of one typical load test with all soil
and footing instrumentation shown.
4.1.1
Spread Footing Construction
ARer excavatingthe holes with a backhoeand hand finishing with shovels,a mat type
reinforcement cage was placedjust~off the bottom of the footing excavationusing #I 1 rebar, 150
mm center to center in both directions. Prior to concrete placement,three 120 mm diameter PVC
sleeveswere placed within the footing to serveas conduits through which the drilling of the
telltales would take place. The footings were formed and poured at a rate of approximately two
footings per day.
26
L
0.91 m
lm
I*
4.25 m
Drilled
Shaft
I
1
(F-L-7
El
Footing
1.5 m
4
L---4
Drilled
Drilled
Shaft
Footing
3
0.91 m
-3m-
Figure 4.1: Footing/Pier Layout
27
Shaft
T
2m
-l
8.5 m
Table 4.1: As-Built Footing Dimensions
4.1.2
Reaction Shaft Construction
Construction of the shaftswas completed at a rate of one shaft per day. A large crane
mounted rotary drilling rig was usedto auger the shaft holes. After installing a 1.52-m deep,
1.07-m diameter casing, placed to protect the top of the shaft, the remaining shaft hole was drilled
with drilling mud until an inspection of the waste material showed definite signsthat the hole was
into the shalelayer near a depth of 12.0-m. At this point, a secondcasing, 1.02 m in diameter and
14.5-m long was placed into the hole and plugged 1 m into the shalelayer. With the casing
plugged into the shalelayer, the drilling mud was evacuatedfrom the casingand the remaining
shaRand bell drilling was done in the dry. After the diwidag bars were put in place, a 12-m
tremie was used to pour concrete down the center of the bars. Concrete was poured to just above
the shalelayer as determined by a measuringtape. A sandplug was placed, followed by a
sand/cementmixture to the ground surface.
4.1.3
Horizontal
Displacement Measurements (Inclinometers)
In order to evaluatethe horizontal displacementof the soil surrounding the footing group,
six vertical inclinometer casingswere installed at locations designatedspt-1 through spt-6 on
Figure 4.3. The casingswere installed prior to footing construction with one casingplaced at
each StandardPenetration Test hole to a depth of 15.2 m. A casingconsistedof 3.0-m long
sectionsof 70-mm outside diameter PVC pipe with vertical running grooves and locking
connections.
28
a.5
m
SAND
Inclinometer
Casing
m
/
15 m
Diwidag bars
No concrete.
only.
CLAY
’
SHALE
Drilled Shaft
(Concrete
+ Bars)
1-
Figure 4.2: Load Test Setup
29
bhst
cht
apt
dmt
pmt
sb
spt
=
=
=
=
=
=
=
Borehole Shear Test
Crosshole Test
Cone Penetration
Test
Dilatotieter
Test
Pressuremeter
Test
Step Blade Test
Standard
Penetration
Test
0
bhst-3
+
TOE OF
SLOPE
SEE FIGURE 2
TOE OF
EMBANKMENT
SEE FIGURE
cpt-1
0
5x1r - A,“+,
sPt-40pnt~~t-2
0
spt
0-
0
cht-4
5
;
-
;
cht-5
cht-2
dmt-1
spt-1
cht-1
0
dmt-2 ;-..;-,
A
Auger
hole for
trlaxlal/resonant
column
1
bhst-1
I
I
bhst-2
LO-,
dmt-4
0
Figure 4.3: In-Situ Field Testing Layout with Auger Hole Location
30
The layout of the inclinometer casingsshown on Figure 4.3 was designedprimarily to
facilitate the cross-holewave test as one sourcehole and two recording holes were required for
eachtest. This layout enabledmultiple inclinometer tests to be performed at various distances
from the footing edge for the samefooting test. Single inclinometer tests were performed for the
1.0-m and 1.5-m footings.
4.1.4
Vertical Displacement Measurements (Extensometer)
Vertical displacementmeasurementswere taken at 0.5B, 1.OBand 2.OB depths for each
footing (Figure 4.2). Extensometertype telltales were designedand constructed as shown in
Figure 4.4 to measurethe movement at a particular depth during loading. The telltales were
designedto prevent friction related settlementbetween the sandand telltale.
4.1.5
Footing Displacement Measurements
The movement of the footings during load testing was carefully monitored by an electronic
data acquisition systemsupplied by the FederalHighway Administration. Linear Variable
Differential Transformers (LVDT’s) were usedto measurethe vertical displacementat each
footing corner and at eachtelltale during load testing. The precision of measurementachievedby
the LVDT’s was on the order of 0.0025 mm over a total stroke of 100 mm.
The LVDT’s were connectedto a specially designeddata acquisition box, which had the
capacity of handling over 16 channelsof data. Data was recorded using a portable Compaq
486DX computer which ran a program specifically designedfor the data acquisition system
provided by FHWA. The computer program was designedto read the LVDT’s at 1, 3, 5, 7, 10,
15, 20, 25 and 30 min for normal testing and this same30-min schedulefollowed by hourly
readingsfor a total of 24 h during the creep tests.
Severalcrib and beam systemswere usedto support the data acquisition systemduring
load testing. The initial systemusedwooden referencebeams,constructed as I beamswith
stackedwooden cribs providing end support. When it was discoveredthat the wooden beams
were creeping faster than the footings during several24-h creep tests, the referencebeamswere
replacedwith loo-mm2 steel box beams, Severalcrib systemswere used in conjunction with the
31
Steel Extension
Bottom
P/ate
Rod
and
72 mm
PVC Tube
75 mm
Circular
Foam
Membrain
Collapsible
Sand
After
Pad/
Backfill
installation
Extension
isolator
6 mm
Dia.
Rod
Tube
Steel Extension
Rod
Top View
75 x 6 mm
Steel Bottom
.60
Cross Sectional
mm
Long
Circular
Plate
Nails
View
Figure 4.4: Cross Sectional View of Telltale
32
steel box beamsincluding stackedwooden cribs, driven stakesand other footings as end supports.
The different crib systemswere used in an attempt to minimize any crib settlement causedby the
weight of the beams.
4.1.6
Load Measurements
Figure 4.2 shows the loading systemused during the load tests. The load applied to each
footing was provided by a 12 MN, center piston, single acting hydraulic jack. The jack had a total
stroke of 127 mm and required shimsto complete the 150 mm of settlement. A 12 MN, 200 mm
diameter compressionload cell was placed between the jack and the shim plates in order to
accurately measurethe load application. The reaction beam usedwas actually four W33x120
beams,welded at the top flangesto produce two beamsplaced side by side to form one large
reaction beam.
4.2
SOIL INVESTIGATION
4.2.1
General Soil Description
The upper soil (to a depth of 11 m) is a medium densesilty fine silica sand. The grain size
distribution curve is relatively uniform with most of the grain sizesbetween 0.5-mm and 0.05-mm.
The sandis probably lightly overconsolidatedby dessicationof the fines and removal of about 1 m
of overburden at the location of the spreadfooting tests. Below the sandlayer is a clay layer
which exists until a depth of at least 33 m. Figure 4.5 showsthe general layering at the site. A
seriesof field and laboratory tests were performed in order to characterizethe material on site.
Table 4.2 gives a list of the tests performed, the datesthesetests were performed and the people
involved in the tests.
4.2.2
Laboratory
Tests
Visual classification, sieveanalysis,Atterberg limits, water content, relative density,
minimum and maximum void ratio, specific gravity and unit weight tests were performed at Texas
A&M University on samplesobtained from both a drilling rig and a hand auger. The
33
--v-v-----__-
REMOVED OVERBURDEN
VARIES BETWEEN 0.5 & 1.5 m
0 m
MEDIUM DENSE TAN SILTY
FINE SAND
3,5 i-7
4,Y m 4_
MEDIUM DENSE SILTY
<7n
SAND W/CLAY
5 m
& GRAVEL
t
MEDIUM DENSE SILTY
SAND TO SANDY CLAY W/GRAVEL
-
10 m
11 m
VERY HARD DARK GRAY CLAY
*
‘33
m
Figure 4.5: General Soil Layering
4.6. Tests performed on drilling rig samplesinclude sieve analysis, Atterberg limits and water
‘content, Sieve analysis results can be seenin Figure 4.6 while an Atterberg limit test, performed
on a clay sample taken at a depth of 16.4 m, indicates a liquid limit of 40, a plastic limit of 19
and a plasticity index of 2 1. Water content results from samplesobtained using a drilling rig
ranged from 11.1% to 33-5% for the sandand 21.7% to 36.7% for the clay. The variation in
moisture content between the hand augeredand drilling rig samplesis due to the severeseasonal
moisture fluctuation which occurs in the testing area. The load tests were performed during the
late summer months, as were the hand augeredsamples.
Consolidated/DrainedTriaxial tests were also performed at Texas A&M University.
Thesetests were performed on remolded samplesof material taken from a hand auger. The
values of 4 calculated from thesetests are:
at 0.6 m depth: (I = 34.2 degrees
at 3.0 m depth: $ = 36.4 degrees
34
Table 4.2: Test Dates & People Involved
Mr. Robert Gibbens
Buchanan/SoilMechanics
Mr. Philippe Jeanjean
Mr. Robert Gibbens
Mr. Rajan Viswanathan
Resonant Column Tests were performed at Texas A&M University. The results of these
tests can be found in Gibbensand Briaud, 1995.
4.2.3
Field Tests
The location of eachfield test can be seenin Figure 4.3.
35
Table 4.3: Dry Hand Augered Samples:Test Results
Maximum Dry Unit Weight (kN/m3)
Minimum Dry Unit Weight (kN/m3)
Liquid Limit
Plastic Limit
USCS Classification
Natural Void Ratio
Dry Unit Weight (kN/m3)
Natural Moisture Content (%)
Natural Unit Weight (kN/m3)
15.70
13.35
N/P
16.10
13.66
N/P
SP
0.78
14.55
5.0
15.28
SP-SM
0.75
14.91
5.0
15.65
4.2.3.1 StandardPenetration Tests w/EnerrrvMeasurements
StandardPenetration Tests (SPT) were performed on site in the spring of 1993, including
tests with energy measurements. Six SPT tests were performed using a safety hammer. Range
plots of N-values versusdepth can be seenon Figure 4.7.
The results of energy measurementstaken during one SPT test indicate that the data
obtained was achievedwith an averageenergy efficiency of 53%.
4.2.3.2 PiezoCone Penetration Tests
PiezoCone Penetration Tests (CPT) were performed on site in the winter of 1993, Five
CPT soundingswere performed and included pore water pressurereadings. Range plots of
averagepoint resistanceversusdepth can be seenon Figure 4.8.
4.2.3.3 PressuremeterTests
PressuremeterTests (PMT) were performed on site in the winter and spring of 1993.
Four PMT tests were performed using a TEXAM Pressuremeter.Range plots of initial modulus
(E,), reload modulus (ER), and limit pressure(pl) versusdepth can be seenon Figure 4.9.
36
MECHANICAL
U. S. Standard
Sieve
in Inches
Openings
ANALYSIS
U. S. Standard
Sieve
C H A- R T
Numbers
Hydrometer
10
20
33
E,l~l~l;
I
9
;
1111I
llllI
;
I I
I I
\I
n
I
I
\I\\
I\\
1111II I I\ I\\\
z
-50 .E
a
II
INII I I I
I
llllIII
I
I
5
Y
70 g
90
90
III1
5
0.5
1
Grain
I
GRAVEL
Coarse
BORING NO.:
DEPTH:
A
A
e
Fine
1 Coarse
I
SAND
Medium
IJNIFIEO SOIL ClASSIFlCATlON
SPT-2
1.4m-1.8m
3.5m-4.0m
4.6m-5.0m
8.7m-9.1
m
0.1
Size
0.05
llllI
I
llllII
Oil
I
I
I I I
0.005
SILT Ok
Fine
-
BORING NO.:
DEPTH: I
CORPS OF ENGINEERS.
CLAY
U. 5. ARMY
HAND AUGERED HOLE
0.1 m
2.5 m
TEXAS A&M RESEARCHPROJECT
RIVERSIDE CAMPUS
Figure 4.6: Grain Size Analysis
MAY 28.
1
0.001
in Millimeters
1
SiSlEM
I
1993
*n-l
.“”
-10
-12
10
0
30
20
40
50
60
Blows Per 0.3 m
Figure 4.7: Range of SPT Results
,,
--1------
a -6
&(
’ -8
__,,
9 --,-
-_---/
------
-;------
-10 c
-12
0
3
6
9
12
Point Resistance (MPa)
Figure 4.8: Range of 5 CPT Soundings
38
15
18
4.2.3.4 Dilatometer Tests
Dilatometer Tests (DMT) were performed on site in the spring of 1993. Three DMT tests
were performed with axial thrust measuredduring one of the three tests. Range plots of
dilatometer modulus (Ed), material index (Id), and horizontal stressindex (Kd) versusdepth can
be seenon Figure 4.10.
4.2.3.5 Borehole ShearTest
Three Borehole ShearTests (BHST) were performed on site during the spring of 1993. A
range plot of phi angle, $ versusdepth can be seenon Figure 4.11.
4.2.3.6 Cross-Hole Wave & SteppedBlade Tests
Cross-Hole Wave & Stepped Blade Tests were performed on site during the spring of
1993. The results of thesetests can be found in the Gibbensand Briaud, 1995.
4.3
RESULTS
The results of this load test program have been divided into four major areas: load
settlement curves, creep curves,inclinometer profiles and telltale profiles.
4.3.1
Load Settlement Curves
Figure 4.12 shows the load settlementcurvesfor each of the five footings. The word
monotonic in Figure 4.12 refers to a load settlementcurve with a constantly increasingload. All
unload/reload cycles have beenremoved from the monotonic curve. The curveswere generated
by taking the settlement reachedafter 30 mm for eachload step during the tests. The settlement
was the averageof the settlementat the 4 corners and the load was given by the load cell. The
data reduction for the load settlementcurveswas done in a conventionalway as describedin
Gibbensand Briaud, 1995.
4.3.2
Creep Curves
Figures 4.13 through 4.16 show creep exponent curves generatedduring load testing for
39
-10
I
I
i
I
ILI/i.&I1_1
-12
0
3
4
6
9
1
.LILLL
G 1
-
.i--,
:
12 15 0 153045607590
Eo (MPa)
I
..A..--I.-.-L-
'
40;1;;;1200
0
20
Er (MPa)
Figure 4.9: Range of PMT Results
-10
-12
0
40
80
Ed (MN)
120 0
2
4
6
Id (MN)
8
Figure 4.10: Range of DMT Results
40
40 60
Kd (MN)
80
Phi Angle (Degrees)
Figure 4.11: Range of BHST Results
the 1.5-m and 3.0-m North footings respectively. The displacements is the displacement at a
time t after the beginning of that load step while sl is the displacement s for t = 1 min. Figures
4.13 and 4.15 show creepresults obtained during a 30-min hold period where a load was held
and the settlementrecorded at specific intervals over 30-min. Figures 4.14 and 4.16 show the
sametype of creep results obtained during 24-h creeptests. All data reduction procedurescan be
found in Gibbens and Briaud, 1995.
4.3.3
Inclinometer
Profdes
Figures 4.17 and 4.18 show inclinometer test results for the 1.0-m and 3.0-m North
footings respectively. Figure 4.17 representsan inclinometer test, performed in the North-South
direction (the direction of maximum movement) at a failure load of 1.78 MN and 150 mm of
settlementfor the 1.Om footing. Figure 4.18 representsthree inclinometer tests, also performed
in the direction of maximum movement (North-South) at failure for the 3.Om North footing.
41
Load Settlement Curve - All Footings
Average 30 Minute Monotonic Curves
0
-20
I
-40 I
t
1 -80
4
* -100
--
J
12
Load (MN)
/-cl-Om
+ l-Sm
+-Mm
--+ 3-O m(n) +- 3-Om(s)
Figure 4.12: 30-Minute Monotonic Load Settlement Curves for All Footings
42
Individual Creep Exponent Curves
1.5 M Footing
0.08 i
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Log Time (minutes)
j -a- 1.34 MN -a- 1.74 h4-N+
2.00 MN L
2.27 MN A-
2.54 MN -++- 2.80 h4N I
Figure 4.13: Individual Creep Exponent Curves for 1S-m Footing, 1.34-M-N- 2.80~MN
43
Individual Creep Exponent Curve
1.5 M Footing - 24 Hour Creep Test
,^ 0.08
e
25
i_____-l------L_-----l------~------~------~------,
I
I
I
I
I
______
+
q
I#
N
I
I
I
I
I
I
/
i-----,------2------~------I------l
I
I
I
~-----J------L
/
J
..A
d
-___
I
’
-r------
!/ii
;
;
i ,/.
i ,..
I
I
I
I--,~‘---i------;---?.--.L-----i
,*”
o-o0
i ,.
0.0
;
0.5
/
1.0
I
I
1.5
I
I
2.0
I
2.5
3.0
/
3.5
Log Time (minutes)
Figure 4.14: : Individual Creep Exponent Curve for 1.5-m Footing - 24-Hour Creep Test
44
Individual Creep Exponent Curves
3.0 M Footing
NORTH
I
I
1
I
I
I
I
I
I
I
I
I
I
1
I
I
i
/
I
---
0.0
0.2
0.4
0.6
0.8
- I- -
1.0
-
-
_ -:
----
1.2
i----.
1.4
1.6
Log Time (minutes)
+
6.23 MN
--&- 7.12MN
-+- 8.Oi MN
+
8.90 MN
-A-- 9.79MN
-B-- 10.24 MN
I
Figure 4.15: Individual Creep Exponent Curves for 3.0-m(n) Footing, 6.23~MN - 10.24~MN
45
lndivldual Creep Exponent Curve
3.0 M Footing - 24 Hour Creep Test
NORTH
1
I
I
1
I
I
,
--
FM
v1
‘33
0.08
--
c
----
----
I
I
c------i-----I
I
!
I
I
I
1
I
L-----l------
/
I
I
/
I
I
I
/
I
I
(
I
I
1
I
I
0.00 i/
/
i
i
0.0
0.5
1.0
1.5
2.0
I
/
j
2.5
3.0
3.5
Log Time (minutes)
Figure 4.16: Individual Creep Exponent Curve for 3.0-m(n) Footing - 24-Hour Creep Test
46
The three inclinometer curves represent three tests performed at various distances from the
footing edge. All data reduction procedurescan be found in Gibbensand Briaud, 1995.
4.3.4
Telltale Profiles
Figure 4.19 shows a plot of settlementversusdepth below the footing bottom for the 3.0m South footing. The results were obtained by reducing telltale data recorded during each
footing load test. Each axis of Figure 4.19 is normalized in order to allow easycomparisons. The
settlement s is the downward movement of the soil at a depth 2 while s(top) is the settlement at
the top of the footing at the sameload. The various curveson the graph refer to different stop
values expressedas percentagesof B (l%, 2%, 3%, 4%, 4%). The correspondingpressurescan
be found in Figure 7.4. Section 7.3 shows how to obtain the strain vs. depth from this curve and
gives the mean results, All data reduction procedurescan be found in Gibbensand Briaud, 1995.
47
1.78 MN Failure Test
1.O M Footing - spt-6 (North-South)
0
-1
-y--g&
-2
-3
4
-5
-9
-10
-11
-12
-13
-14
-20
-16
-12
-8
0
4
4
8
12
16
20
Deflection (mm)
Figure 4.17: Inclinometer Test - 1.78~MN Failure Load - N-S Direction, 1.0-M Footing
48
8.90 MN Failure Test
3.0 M Footing - North (North-South)
I-
-9
-10
-,------+---
-,-----+---
-----I--
--+----1
----
+ ----
-11
-12
-13
-14
-20
-16
-12
-8
4
0
4
8
12
16
20
Deflection (mm)
-m- spt-3 -A- q-2 +
spt-1
Figure 4.18: Inclinometer Test - 8.90~MN Failure Load - N-S Direction, 3.0-m(n) Footing
49
S/S(top) versus Depth
3.0 M Footing South
,
I
I
I
/
I
I
I
I
_ L -
I
i 1
Ii
: :
/
j
--
-.
-.
-
-
I
I
L--I
I
- I- _
I
I
I
I
I
I
I
I
1
I
I
_ I
-
-
--
- ‘_
I
I!I /
.i----I---I
I
I
I
I
I
I
I
--I-
--
--
:
I--I
I
I
1
I
I
I
_‘---:
.-
--
i
--
I---I
I
I
I
I
1
I
I
l---I
I
----
0.0
i---I
I
I
’
’
j,
0.1
’
’
I
0.2
’
0.3
’
Iii
I
0.4
0.5
(
0.6
1
I
I
I
I
I
I
I
/
-3.0
1
I
0.7
I
I
I
I
0.8
I
II
0.9
I
j
1.0
S/S(top)
;f
1%+2%-&3%+--4%-&S%
I
Figure 4.19: Settlement Versus Depth for 3.0-m(s) Footing With Varying Percentagesof B
50
5. COMPARISON
5.1
PREDICTION
BETWEEN
SYMPOSIUM
PREDICTED
AND MEASURED
RESULTS
EVENT USING THE 5 FOOTINGS
This part of the project is detailed in Briaud and Gibbens, 1994.
5.1.1
Introduction
Five squarespreadfootings ranging in size from l-m to 3-m were load tested to 0.15-m of
penetration. In parallel, a prediction event was organized. The prediction event was advertisedin
ASCE News and at various conferencesin early 1993. A flier was distributed worldwide to the
approximately 6,000 membersof the ASCE GeotechnicalEngineering division. About 150
requestsfor a prediction packagewere received. The 150 prediction packageswere sent in July
of 1993. During the following 2 months, three addendumswere sent: an errata on the prediction
package,an as-built set of dimensionsfor the footings and the time dependentmodulus data from
PMT tests. The prediction packageand the addendumsare given in Briaud and Gibbens, 1994.
A total of 3 1 predictions were receivedfrom Israel, Australia, Japan,Canada,USA, Hongkong,
Brazil, France and Italy. Of the 3 1 written responsesobtained, 16 were from academicsand 15
were from consultants.
5.1.2
The Prediction Request
The participants to the prediction event were requestedto predict certain quantities
obtained from eachfootings 30-min load-settlementcurve (Figure 5.1). The first request was to
predict, for eachfooting, the load measuredin the load test at a settlementof 25-mm on the 30min load-settlement curve. The secondrequestwas to predict, for eachfooting, the load
measuredin the load test at a settlementof 150 mm on the 30-min load-settlement curve. The
third request was to predict what the creep would be for the 3- by 3-m footings between the land 30-min readingsat a load correspondingto a total footing settlementof 25-mm. The fourth
requestwas to predict the total creep in the year 2014 if this load were held for 20 years.
51
Load
1 minute
load/settlement
curve
Settlement
L 30 minute
load/settlement
curve
\
Figure 5.1: Load-Settlement Curve
5.1.3
Prediction Results and Comparisons
Tables 5.1 and 5.2 show summariesof the prediction methods and soil tests used in the
3 1 predictions respectively.
The predicted results (Tables 5.3 and 5.4) were comparedto the measuredresults (Table
5.5 and Figure 4.12) by presenting a seriesof frequency distribution plots (Figures 5.2 through
5.11). Figures 5.2 through 5.6 give frequency of occurrenceof the ratio of the predicted load at
25 mm of settlement over the measuredload at 25 mm of settlement for the five footings.
Figures 5.7 through 5.11 give the frequency of occurrenceof the ratio of the predicted load at
150 mm of settlement over the measuredload at 150 mm of settlement for the five footings.
Inspection of the Q~CJ
frequency distribution plots indicates that 80% of the time the
predictions were on the safe side and that this number was relatively independentof the footing
scale. This is an indication that the scaleeffect is properly taken into account in settlement
analysis.
Inspection of the Q 150frequency distribution plots indicates that on the average63% of
the time the predictions were on the safe side. This number however varied significantly from
52
Table 5.1: Methods Used
1
2
1
18
3
5
6
Party
Peck
Robertson & Campanella
Schmertmann
Schultze & Sherif
Terzaghi & Peck
Vesic
Table 5.2: Soil Tests Used
53
Table 5.3: Prediction Results for Q25 and Qlso in kN
No.
ul
P
Authors
1
Wisemau
2
Poulos
3
Siddiquee
4
Silveti
5
Horvath
6
ThOUUS
7
SlUendra
8
chang
9
Brahms
10
Floess
11
Boone
12
Cooksey
13
SUMIt
14
Townsend
15
Foshee
16
Mesri
17
Ariemma
18
Tand
19
Funegard
20
Des&amps
21
Altaee
22
Decourt
23
Mayne
24
Kuo
25
ShahIour
26
Abid
27
Utah State
28
Gottarcli
29
Chua
30
Bhowmik
31
Diyaljee
MeZIll
Standard Deviation
Measured Value
Q25
lm
670
800
59
448
900
374
800
150
720
700
600
550
620
404
423
925
1100
850
850
900
600
779
330
320
275
550
838
935
313
550
422
605
257
850
Q25
1.5 m
1300
5040
116
771
1450
450
2590
320
775
1500
1100
900
1250
2100
564
1475
1165
1550
1570
1800
1100
1295
950
650
450
1000
1644
2008
540
800
788
1258
899
1500
Q25
2.5 m
3000
2560
295
1488
3125
1786
4020
1000
1850
4300
2400
2100
2380
3500
1190
2775
3750
3000
3370
2700
1900
2740
3350
2000
740
2600
3087
4271
1009
2000
1801
2454
1028
3600
Q25
3.0 m(s)
3900
2790
407
1929
4500
1226
4780
1400
1550
5600
1750
3750
3000
5400
655
3325
1250
3700
4470
5200
2300
4658
5200
2650
1530
3600
4808
5526
1452
2800
2552
3150
1582
4500
Q25
3.0 m(n)
3900
3690
415
1929
4500
2835
4780
2370
3025
6400
3000
3700
3300
6080
1838
3325
5480
3700
4470
5200
2300
4290
5200
3 100
1530
3300
4668
5446
1456
3000
2526
3573
1439
5200
Quo
Q150
lm
1120
1120
200
1085
1650
457
800
450
1100
1000
760
900
850
1603
2104
Q150
1.5 m
2600
11340
422
2143
4200
650
2640
500
1990
2400
2150
2000
2400
7195
2720
Q150
2.5 m
7900
9680
1086
5060
13500
2927
4690
2600
9630
7700
7000
6400
9600
12804
5949
Q150
3.0 m(s)
11300
14580
1326
6857
23000
1633
13960
3600
8450
11500
10000
9000
15800
16620
2641
3.0 m(n)
11300
12690
1502
6857
20000
4847
13960
5000
15200
11600
10000
9000
15800
22835
9016
3965
960
960
1500
2500
2360
395
420
887
1600
900
1093
501
1100
613
1165
771
1740
5155
2170
2170
3400
4300
4490
1260
970
2397
3000
2119
3 143
937
2500
1576
283 1
2163
3400
14980
6020
6020
5400
8000
16440
5150
3500
3720
8000
7375
10918
2413
9000
5280
7291
3743
7100
5220
8830
8830
10800
10000
27945
8450
5400
7560
12000
15143
17379
3320
14000
7293
10415
6063
9000
21575
8740
8740
10800
10000
25740
8450
5500
7560
11500
13943
16587
3345
15000
7219
11477
5799
10250
No. of Predictors
withill 20%
5
1
0
0
6
0
4
0
2
5
3
4
1
4
4
3 of5
2
7
8
8
3
4
5
0
1
5
6
4
0
0
1
5
Table 5.4: Prediction Results for A, and 52014
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
1g
19
20
21
22
23
24
25
26
27
28
29
30
31
Mean
Authors
Wiseman
Poulos
Siddiquee
Silvestri
Horvath
Thomas
Surendra
Chang
Brahma
Floess
Boone
Cooksey
Scott
Townsend
Foshee
Mesri
Arienuna
Tand
Funegard
Deschamps
Altaee
Decourt
Mayne
Kuo
Shahrour
Abid
Utah State
Gottardi
Chua
Bhowmik
Diyaljee
Stndrd Deviation
Measured Value
As South
A, North
mm
13
1
1.3
1
1.5
mm
13
I
S2014
South
mm
36
37
S2014
North
mm
36
37
1.3
31
31
1
10
10
1.5
3
35
36.5
6
32
33
32
30
37
35
36.5
3
31.5
33
32
30
37
38
32
105
38
32
30
3
2.5
2.8
2.4
1
1
1.5
2
2
1.3
1
-
1.3
1
21
2.8
2.8
20.5
2.8
2.8
1.3
1.3
37
32
102
38
32
30
3
2
3
2
44.3
44.3
16
16
27
27
1.5
1.5
25
40.58
29.7
187.3
35
64
42
34
25
40.54
29.7
186.9
32
64
41
35
-
3
3
1.1
1.1
5.8
5.8
1.6
1.4
6
4
5
2.9
6
4
5
2.4
55
Table 5.5: Measured Results
Load for 25 mm
of settlement425
on the 30-min
load settlement
curve (kN)
Load for 150 mm
of settlementQ 150
on the 30-min
load settlement
curve (kN)
Creep settlement
between 1 and 30min 425 curves,
As (md
Settlementin the
year 20 14 under
Footing 1
3m
North
Footing 2
3m
south
Footing 3
2.5 m
Footing 4
1.5 m
Footing 5
l.Om
5200
4500
3600
1500
850
10250
9000
7100
3400
1740
2.4
2.9
X
X
X
?
?
X
X
X
4259 A2014 (mm)
84% for the l-m footing to 48% for the 3-m South footing and showed a clear decreasingtrend
with increasing size. This is an indication that the scale effect is not properly taken into account in
predicting the load correspondingto a large displacement.
Predicting the load at 150 mm of displacement created a dilemma for the participants:
could this be consideredenough displacementto use a bearing capacity equation or not? Most
consideredthat the answerwas “Yes.” Others used the FEM with a nonlinear model or did a
non-linear extension of their settlementmethod.
If one considersall the answerswhich were within +20% of the measuredloads, it is
possibleto count how many such answerseachparticipant had (Table 5.3). This number would
have a maximum of 10. The best resultswere from participantswhose answersfell within the
+20% range 8 times out of 10. The two participants who achievedthis remarkable result used the
MenardBriaud pressuremetermethod for one and an averageof 15 simple methods plus the FEM
for the other,
56
0.10 '0.30 '0.50 '0.70 '0.90 '1.10
1.30 '1.50 '1.70
Q(pred.)/Q(meas.)
Figure 5.2: Distribution of Qpred,/Qmem.for 25-mm Settlement: 3-m North Footing
,----f---f--------T---T----L---I-----
0.10
0.30
0.50
0.70
0.90
1.10
1.30
1.50
1.70
Q(pred.)/Q(meas.)
Figure 5.3: Distribution of Qpred./Qmeas,
for 25-mm Settlement: 3-m South Footing
57
I
I
I
I
I
30 I
26~-----~----~---~---:---~~~~~p,_=_3_1~_--:-----
0.10 '0.30 '0.50 '0.70 '0.90 '1.10
1
I
I
1.30 '1.50 '1.70
Q(pred.)/Q(meas.)
Figure 5.4 Distribution of Qpred,/Qmea. for 25-mm Settlement: 2.5-m Footing
24 :
Tbtal Nb. = 311
I
+---+---,----,----,------r----+----.-I
I
I
I
’
---~-:----L---l----!-~-~!~-~-,---_’
----J.-e--
22 +- _--_:--_820+-
I
31&t316$-
s
814f012f
h
O IO +-
--i
i
I
Q(pred.)/Q(meas.)
Figure 5.5 Distribution of Qpred./Qmeas
. for-25 mm Settlement: 1.5-m Footing
58
26 T
---24 +
?
q22
e20
8
g
18
I
I
I
I
I
I
I
I
Tbtal N8 =311
-,-- --~---+---1----,----,~------+
-- ------- ---------l---T
,----L---J.
-I-
-
-
: _____
- l----‘---l----‘---I-----
I
-----I----
,----;---;-----
-----
----i---T-----
g;::0
‘“0 12 -AlO -8 8-g 6-13!
cr( 4-2-
0 It
+-------I-----
0.10 '0.30 '0.50 '0.70 '0.90 '1.10 '1.30 '1.50 '1.70
Q(pred.)/Q(meas.)
Figure 5.6 Distribution of Qpred,/Qmeas.
for 25mm Settlement: 1.0-m Footing
26
I
!
24
822
0 20
3 18
8 16
8 14
0
‘“0 12
h10
38
I-T
!
w
$4
-r-
T--
--
~---;---r---,---1-
I
I
I
I
I
j
I
I
ToqLNa~30~~---+-~-
1
Et
f+?
I
r-i
+-
T
-r2 +-
0
0.125 0.375 0.825 0.875 1.125 1.375 1.625 1.875 2.125 2.375
Q@red.)/Q(meas.)
Figure 5.7: Distribution of Qpred./Qmeas.
for 15knn-1 Settlement: 3-m North Footing
59
28
,
I
I
-24
-/---
--,--
’
LT---r
---,-
I
: Totd No. f 30 I
26~----~---~---r---/----:---:---~---~---~-
____
1
---,---‘---T---“---,-----~
-,---t---t---,----,-----
--+----f----+---+----+---+---
,_-
_-I-__
+---+---,------I-----
__,----I-----
Q(pred.)/Q(meas.)
Figure 5.8 Distribution of Qpred./Qmea,for 15OqnmSettlement: 3-m South Footing
34
22 j-__-J--_c--.r---:---__T_o~~lNo,~-3~_I__-_I-__,_
~20~----1---t---i---i---‘-9
18
/
’
-I---L---L---I
I
I
’
I
’ ---I
-
C-----!---l---~---‘----l---l---L---I-_--I--__I
/
-I-
-
-
-
-
--
I
_,_
-
-
-
-
--
-I_
-
-
-
_
--
---
0.10 0.30 0.50 0.70 0.90 1.10 1.30 1.50 1.70 1.90
Q6pred.)/Q(meas.)
Figure 5.9: Distribution of Qpred,/Qmes.for 1SO&mmSettlement: 2.5-m Footing
60
40
I
I
I
i
36
----
t
332
I
7--I
1
I
/
I
1
I
I
I
I
/ ‘--I
4---- A--828
7
%
----A---L--- , ~;---l---‘824
+----t--t---lrn,
8 20
3
Al6
I
m
----i---A----
i
----
::k~~
+---+---
i@
I
I
; Tot+No.
I
I
,----‘---4----c-
1
+30
;
;
I
I
I
--L---l----l
I
I
----I
--,----I--.---
----
--,--_-,-
,----,---?---+-
I
812
5
i2
Frc 8
4
0
0.10 '0.30 '0.50 0.70 0.90 '1.10 ‘1.30 1.50 '1.70 1.90
Q(pred.)/Q(meas.)
Figure 5.10: Distribution of Qpred,/Qmeas.
for 15&mm Settlement: 1.5-m Footing
36
1
/
@24
J----+
,
--7
; Tot41 No.” 30 /
I
- - - ,- - -,_ - - _,_ - - T - - _ r _ - -,- - I
- - - - .- - I
I
i---,--------I
I
I
I
I
--_---_--__----------I--
it
Ii@!
”
,+ ____
i
I
I
:---L---l---‘---
I
I
:
I
_,- - - - - 1
I
I
-I- - - - - :
I
I
I
,
I
1
I
I
--l-----,
\
0.10 0.30 0.50 0.70 0.90 1.10 1.30 1.50 1.70 1.90
Q(pred.)/Q(meas.)
Figure 5.11: Distribution of Qpred./Qmeas.
for 15hm
61
Settlement: 1.0-m Footing
An attempt was madeto find out which method was the most consistently successfulat
predicting the loads at 25 and 150 mm. The top 10 answersfor eachof the loads to be predicted
was studied. It was not possibleto detect a clear best method. What becameclear, however, is
that very few participants actually usedthe exact procedure recommendedby the authors of a
method. Instead, many participants used a given method but modified it by taking into account
their own experienceor by using part of another method. Severalparticipants used an averageof
severalmethods as their answer.
Reasonablepredictions were obtained for As consideringthe lack of directly useful data in
the prediction package. Most participants used someform of Schmertmann’stime factor or the
time dependentpressuremeterdata sent in the addendums.
The predictions for A2014indicate that an additional 10 mm should occur over the next 20
years. Provided funding can be secured,the plan is to place a load of 5200 kN on the 3-m North
footing and 4500 kN on the 3-m South footing for the next 20 years and to organize another
conferencein the year 2014.
5.1.4
Predicted Design Loads and Factor of Safety
The participants predicted 425 and Ql50, In a typical design, one usesa factor of safety
of 3 on the ultimate load QUand usesas the design load the minimum of the load leading to 25
mm of settlement and one third of the ultimate load. For the purpose of this exercisethe
predicted design load for eachparticipant was taken as:
Qd = Mm( Q25(predicted) YQ 15O(predicted)/ 3,
(1)
Thesevalues are listed in Table 5.6. The measuredload at 150 mm, Qljo, of settlement
was taken as the measuredfailure load Qf and the ratio of Q$Qd was consideredto be a safety
factor. The valuesof this factor of safety are given in Table 5.7. This table shows that in only one
instancethe factor of safety Qf/Qd was lessthan one, and that the next worst casewas 1.6.
Therefore nearly all predictions lead to safe designs,
62
Finally the settlementthat would take place under the designload was obtained. This was
one by using the design load, Qd, for eachparticipant and reading the corresponding settlement on
the measuredload settlement curves(Figure 4.12). These settlementvaluesare in Table 5.8. As
can be seen,most settlementsare quite acceptable. A trend is noticed where the larger the
footing the higher the settlementunder designload.
5.1.5
General Observations
Five large spreadfooting load tests were performed. The squarefootings varied from 1 m
to 3 m in width and were loaded until the settlementreached 150 mm. Participants were askedto
predict the loads (425 and Q150)necessaryto create 25 and 150 mm of settlement after 30 min of
load application as well as the creep settlementover 30 min for the 25-mm load and the
settlementby the year 2014 under the 25 mm load. A total of 3 1 predictions were receivedfrom
8 different countries, half from consultantsand half from academics. Some observationsreached
from comparing the predictions and the measurementsare as follows:
1.
Nobody gave a complete set of answerswhich consistentlyfell within &20% of the
measuredvalues. Two participants had 80% of their answersfalling within the &20%
margin of error.
2.
The load creating 25 mm of settlement,425, was underestimatedby 27% on the average.
The predictions were 80% of the time on the safe side. The scaleeffect was properly
predicted sincethis number (80%) was consistentfor all sizes.
3.
The load creating 150 mm of settlement,Ql50, was underestimatedby 6% on the average.
The predictions were 63% of the time on the safe side. The scaleeffect was not properly
predicted and there was a trend towards overpredicting Ql50 for the larger footings.
63
Table 5.6: Predicted Design Loads
No.
1
2
3
4
5
6
7
8
9
10
11
Authors
Wiseman
Poulos
Siddiquee
Silvestri
Horvath
Thomas
Surendra
Chang
Brahma
Floess
Boone
Cooksey
Scott
Townsend
Foshee
Mesri
Ariemma
Tand
Funegard
Deschamps
Altaee
Decourt
Mayne
Kuo
Shahrour
Abid
Utah State
Gottardi
Chua
Bhowmik
Diyaljee
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Mean
Stndrd Deviation
Measured Value
Qd
lm
kN
373
373
59
362
550
152
267
150
367
333
253
300
283
404
423
925
1100
320
320
500
600
779
132
140
275
533
300
364
167
367
204
377
229
580
Qd
1.5 m
kN
867
3780
116
714
1400
217
880
167
663
800
717
667
800
2100
564
1475
1165
723
723
1133
1100
1295
420
323
450
1000
706
1048
312
800
525
892
682
1133
64
Qd
2.5 m
kN
2633
2560
Qd
3 m(s)
kN
3767
2790
295
407
1488
3125
976
1563
867
1850
2567
2333
2100
2380
3500
1190
2775
3750
2007
2007
1800
1900
2740
1717
1167
740
2600
2458
3639
804
2000
1760
2042
866
2367
1929
4500
544
4653
1200
1550
3833
1750
3000
3000
5400
655
3325
1250
2943
2943
3600
2300
4658
2817
1800
1530
3600
4808
5526
1107
2800
243 1
2788
1430
3000
Qd
3 m(n)
kN
3767
3690
415
1929
4500
1616
4653
1667
3025
3867
3000
3000
3300
6080
1838
3325
5480
2913
2913
3600
2300
4290
2817
1833
1530
3300
4648
5446
1115
3000
2406
3138
1338
3417
Table 5.7: Factors of Safety F = Qf/Qd
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Authors
Wiseman
Poulos
Siddiquee
Silvestri
Horvath
Thomas
Surendra
Chang
Brahma
Floess
Boone
Cooksey
Scott
Townsend
Foshee
Mesri
Ariemma
Tand
Funegard
Deschamps
Altaee
Decourt
Mayne
Kuo
Shahrour
Abid
Utah State
Gottardi
Chua
Bhowmik
Diyaljee
30
31
Mean
Stndrd Deviation
MeasuredValue
Q&i
lm
4.66
4.66
29.49
4.81
3.16
11.42
6.53
11.60
4.75
5.22
6.87
5.80
6.14
4.31
4.11
1.88
1.58
5.44
5.44
3.48
2.90
2.23
13.22
12.43
6.33
3.26
5.80
4.78
10.42
4.75
8.52
6.64
5.23
3
Qf’Qd
Q&d
QdQd
1.5 m
3.92
0.90
29.31
4.76
2.43
15.69
3.86
20.40
5.13
4.25
4.74
5.10
4.25
1.62
6.03
2.31
2.5 m
2.70
2.77
24.07
4.77
2.27
7.28
4.54
8.19
3.84
2.77
3.04
3.38
2.92
1.89
4.70
4.70
3.00
3.54
3.54
3.94
3.09
3.74
2.63
8.10
10.52
7.56
3.40
4.81
3.25
10.89
4.25
6.47
2.59
1.93
4.14
3.20
5.00
5.88
2.50
1.87
1.63
8.13
3.21
3.70
6.29
5.90
3
65
2.98
2.03
5.97
2.56
6.09
9.59
2.73
2.89
1.95
8.83
3.55
4.03
4.72
4.12
3
3 m(s)
2.39
3.23
22.11
4.67
2.00
16.53
1.93
7.50
5.81
2.35
5.14
3.00
3.00
1.67
13.74
2.71
7.20
3.06
3.06
2.50
3.91
4.99
4.63
3
Qf/Qd
3 m(n)
2.72
2.78
24.70
5.31
2.28
6.34
2.20
6.15
3.39
2.65
3.42
3.42
3.11
1.69
5.58
3.08
1.87
3.52
3.52
2.85
4.46
2.39
3.64
5.59
6.70
3.11
2.21
1.88
9.19
3.42
4.26
4.43
4.13
3
Table 5.8: SettlementUnder the Design Load, Sd
No.
Authors
1
2
3
4
5
6
7
8
9
10
Wiseman
Poulos
Siddiquee
Silvestri
Horvath
Thomas
Surendra
Chang
Brahma
Floess
Boone
Cooksey
Scott
Townsend
Foshee
Mesri
Ariemma
Tand
Funegard
Deschamps
Altaee
Decourt
Mayne
Kuo
Shahrour
Abid
Utah State
Gottardi
Chua
Bhowmik
Diyaljee
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Mean
Stndrd Deviation
Measured Value
Sd
lm
mm
3
3
.5
3
7
2
2.5
2
3
2.5
2.5
2.5
2.5
4
4.5
28
48
2.5
2.5
6
10
19
2
2
3
7.5
3
3.5
1.5
3.5
2
6.1
9.5
9.5
Sd
1.5 m
mm
6.5
170
1
4
21
1
7
1
3.5
6
4.5
3.5
6
55
3
24
12
4
4
13
13
18
2
1.5
2
9
4.5
10
1.5
5.5
3
13.5
30.9
12.0
66
Sd
2.5 m
mm
12
11
0
3
17
1
3.5
1
4.5
11
8
6
9
27
2
13
33
5
5
4
4.5
12.5
4
1.5
1
11
9
29.5
0.5
5.5
4
8.4
8.4
8.5
Sd
3 m(s)
mm
16
8
0
3
25
0
28
1
2
17
2.5
9
9
47
0
12
1
9
9
15
5
29
8
3
2
14
34
50.5
1
8
6
12.1
13.4
10.0
Sd
3 m(n)
mm
12
12
1
4
18
3
19
20
8
13
8
8
10
36
3
10
30
7.5
7.5
12
6
17
8
4
2.5
10
20
29
2
8.5
6
11.5
8.6
10.5
4.
A large variety of methodswas used and it was not possibleto identify the most accurate
one becausemost people used publishedmethods modified by their own experienceor
used a combination of methods. The most popular method was Schmertmann’smethod
using CPT data. Of all the soil tests performed, the most used one was the CPT, then
camethe SPT, the PMT and the DMT.
5.
The creep settlement over the 30-min load step for Q25 was predicted reasonablywell
consideringthe limited data availablefor this prediction. The averageprediction for the
settlementby the year 2014 under 425 is 35 mm or an additional 10 mm over the next 20
years.
6.
The design load Qd for eachfooting and eachparticipant was defined as
Qd = M~(Q25(predicted)~QISO(predicted)
/ 3) The factor of safety F was defined as
the ratio of the measuredQl50 over Qd. Since 3 1 participants predicted the behavior of 5
footings, there was a total of 155 valuesfor the factor of safetyF. Only once out of 155
was F lessthan 1, the next worse casewas 1.6; the averagewas 5.4. Therefore it appears
that our profession knows how to design spreadfootings very safely.
7.
The settlement Sd under the designload Qd was read on the measuredload settlement
curves at the value of the predicted design load for eachfooting and for eachparticipant.
The overall averagewas 10.3 mm which is much smaller than 25 mm. Considering the
high factors of safety and the low settlementvalues,the design load could have been
significantly higher. Therefore it appearsthat our professioncould design spreadfootings
more economically.
5.2
EVALUATION
OF 18 PREDICTION
METHODS
USING THE 5 FOOTINGS
This part of the project is detailed in Gibbensand Briaud, 1995.
Tables 5.9 and 5.10 list the results obtained from a study of 12 settlement and 6 bearing
capacity prediction methods.
67
TABLE
5.9: Tabulated SettlementPrediction Values
II
Menard & Rousseau(1962)
Meyerhof - CPT (1965)
Meyerhof - SPT (1965)
Peck & Bazarra (1967)
Peck, Hansen& Thornburn (1974)
Schmertmann- CPT (1970)
Schmertmann- DMT (1986)
Shultze & Sherif (1973)
Terzaghi & Peck (1967)
Measured Load @,s=25 mm
TABLE
1.0 m
1.5 m
2.5 m I 3.0 m(n) I 3.0 m(s) II
0.288
0.195
1.042
0.319
0.455
1.300
1.465
0.287
0.850
0.446
0.416
1.899
0.718
0.734
2.165
2.615
0.529
1.500
0.738
1.ooo
4.144
1.981
1.475
4.114
4.750
1.244
3.600
0.918
1.413
5.679
2.952
1.953
5.256
5.850
1.476
4.500
0.918
1.413
5.679
2.952
1.953
5.256
5.850
1.476
4.500
5.10: Tabulated Bearing Capacity Prediction Values
2.5 m 3.0 m(n) 3.0 m(s)
Footing Footing Footing
(MPa)
(MPa)
(MPa) =
1.389
1.513
1.513
0.781
0.783
0.783
0.769 1 0.730 1 0.730
5.2.1
Settlement Prediction Methods
In an attempt to match the prediction results collected during the symposium,the
calculations made for this study (Table 5.9) were of the load required to causea settlement of 25
mm. Actual prediction method descriptionsand calculationscan be found in Gibbensand Briaud,
1995.
68
5.2.2
Bearing Capacity Methods
In an attempt to imitate the prediction results collected during the symposium,the
calculations made for this study (Table 5.10) were of the load required to causea settlementof
150 mm. Actual prediction method descriptionsand calculationscan be found in Gibbensand
Briaud, 1995.
5.2.3
Best Method
Table 5. I 1 shows the ratio of the meanpredicted load over the mean measuredload for all
settlement and bearing capacity prediction methods, On the basisof thesenumbers,it can be said
that the best methods for settlementare the Schmertmann-DMT (1986) and the Peck and Bazarra
(1967) although they are somewhaton the unconservativeside. The best conservativemethods
are Briaud (1992) and Burland & Burbidge (1984). The best method for bearing capacity was the
simple 0.2q, method from Briaud (1993a). Most other methods were 25 to 42 percent
conservative.
69
TABLE
5.11: Best Prediction Method Determination
IISETTLEMENT
1
2
3
4
II5
6
7
8
9
10
II 11
12
Mean Pred. Load / Mean Meas. Load
0.66
0.62
0.24
0.21
0.21
0.28
1.19
0.57
Briaud (1992)
Burland & Burbidge (1984)
De Beer (1965)
Menard & Rousseau(1962)
I Meyerhof- CPT (1965)
I
:rhofSPT
(1965)
Meyt
Peck & Bazarra (1967)
Peck, Hanson & Thornburn (1974)
Schmetrmann-CPT (1970)
Schmertmann-DMT (1986’1
I
1 Schultze & Sheriff (1973)
I
1Terzaghi & Peck (1967)
BEARING
r1
2
3
4
5
6
I
0.42
1.16
_._1.31
0.32
CAPACITY
1.08
0.61
0.58
0.76
0.59
n hh
1Briaud- CPT (1993a)
Briaud- PMT (1992)
Hansen(1970)
Meyerhof (195 1 & 1963)
Terzaghi (1943)
Vesic (1973 & 1974)
70
II
II
II
6. WAK TEST
6.1
PROCEDURES
This part of the project is detailed in Ballouz, Maxwell and Briaud (1995).
The Wave Activated stiffness(K) test, or WAK test, is a nondestructiveimpact test
that was developedby Briaud and Lepert (1990). The test is useful in determining the static
stiffnessof the soil beneatha rigid mass,such as a spreadfooting. This stiffnessin turn can be
used to evaluatethe load settlementcharacteristicsof the footing and possibly the settlement
under working loads. Such a test could serveas quality control after construction but before
placing the bridge deck or eventhe abutment wall; it could also be used to evaluate spreadfooting
foundations after an earthquake.
The theory is basedon a simplified, linear systemmodel of the soil-footing assembly. This
model consistsof a mass,a spring and a dash-pot, and is frequently used to describethe vertical
vibration of soil-footing systems(Figure 6.1).
The WAK test is performed by striking a footing near its center with a rubber-tipped
sledgehammerthat has been instrumentedwith a force transducer. The impact of the hammer
causesthe footing and a bulb of soil beneaththe footing to vibrate. The velocity of this vibration
is recorded by using two geophoneswhich are placed on diagonally opposite corners of the
footing. This procedure is illustrated in Figure 6.2. More details about the set-up and data
acquisition of the WAK test can be found in Maxwlll and Briaud (1991), and Ballouz and Briaud
(1994).
The force signal, F(t), is the input from the hammer,and the velocity response,v(t), is the
output from the geophones,both in the time domain (Figure 6.3). The measuredmobility in the
frequency domain can be obtained by taking the ratio of the Fourier transformation of v(t) to the
Fourier transformation of F(t). The modulus of this ratio as a function of frequency, 1v/F 1
versuso, is called mobility, or sometimesthe transfer function of the soil-footing system(Figure
6.4). The mobility can also be obtained mathematicallyby using the theory of vibrations.
71
M
I
Figure 6.1: Soil-Footing Model
Soil
Figure 6.2: The WAK Test
72
Figure 6.3: Sample of Time Domain Data Plot
Becauseof the mathematical linearity of the system, the mobility is theoretically a unique
property of the soil-footing model. By curve-matching the theoretical mobility of the model with
the measuredmobility in the experiment, three parameterscan be determined:
1.
2.
3.
the vibrating soil-footing mass,M
the static stiffness of the soil beneaththe footing, K
the damping, C, which describesthe internal damping and energy dissipation in the soil.
73
K=
l.SlE8
N/m
M = 3975 kg
C = 1.33E6 N/m/s
IL----l
0
40
120
Frequency, f (Hz)
80
160
-0.8
-0.6
2000
Figure 6.4: Sampleof Mobility Curve: Theoretical vs. Measured
74
More details about the theory behind the WAK test can be found in Briaud and Leper-t(1990) and
Maxwell and Briaud (199 1).
Actually, the static stiffnessparameterK representsthe slope of the initial part of the static
load-settlement curve as shown in Figure 6.5. When K is predicted by the WAK test, it can be
used to predict the small strain behavior of footings subjectedto vertical loads.
6.2
DATA ANALYSIS
Each of the five footings at the sandsite was tested four times with the WAK test; two
times before and two times after the load tests were conducted. The raw data files are in Ballouz,
Maxwell and Briaud (1995).
The WAK test data was sent to JamesMaxwell in Corpus Christi who was unaware of the
load test results. Static stiffnessresults were obtained by Maxwell using the ANAWAK computer
program (Maxwell and Briaud, 1991). The ANAWAK program automatically matchesthe two
mobility curves (experimental and theoretical) in order to identify the soil-footing parametersM,
K and C. A sampleof the mobility curve match is given in Figure 6.4. The stiffnessK parameter,
representsthe static stiffnessof the soil-foundation system(Briaud and Leper-t(1990), and
Ballouz and Briaud, 1994). The results of the WAK tests performed at the NGES/TAMU sand
site are summarizedin Table 6.1,
6.3
COMPARISON
WITH LOAD TESTS
Five static load tests were performed as part of the researchstudy conducted on the five
spreadfootings. l-OM, l-5M, 2-5M, 3-01M and 3-03M. The load versussettlement curves for
the 5 spreadfootings are presentedon Figures 6.6 through 6.10 (Briaud and Gibbens, 1994).
Stiffnesspredicted by the WAK tests are plotted on the measuredload-settlementcurves for
graphical comparisons(Figures 6.6 through 6.10). The scatterbetween the first set of tests and
the secondset of tests (Table 6.1 and Figures 6.6 to 6.10) shows that the repeatability of the
WAK test is quite good.
These results show that the WAK test predicted a secantstiffnesswhich correspondsto a
75
Load
Figure 6.5: Typical Load-Settlement Curve
76
Table 6.1: Summaryof WAK Test Results
Set Number
& Test Data
Set #l - Before
Load Test,
Oct. 5, 1993
Set #2 - Before
Load Test,
Oct. 14, 1993
File Name of
WAK Data File
WAK Test
Stiffness,K(N/m)
WAK Test
Mass, M (N/m)
1-OM?.DAT
I-SM?.DAT
2-5M?.DAT
3-012M?.DAT
3-OlM?.DAT
3-03M?.DAT
S1-OM?.DAT
Sl-OM?.DAT
Sl-SM?.DAT
SZ-SM?.DAT
S3-OlM?.DAT
S3-03M?.DAT
S3-03HT?.DAT
1.31 E8
1.76 E8
2.19 E8
3.29 E8
3.07 ES
3.20 E8
1.72 E8
1.55 E8
1.51 E8
1.73 ES
2.11 E8
3.11 E8
1.43 E8
1934
3994
10431
21095
19675
18950
324
293
3975
10236
13529
17082
7823
settlement averaging about 10 mm. Therefore the WAK test stiffness KWAKcan be used to
calculate small settlementsby using:
s=
Load on Footing
K WAK
for ( s ( 10 mm
77
Load Settlement Curve - 1.0 M Footing
Average 30 Minute Monotonic Curve
-60
-110
-120
-130
-140
-150
-160
_ -
-,-
/
-
-
I
7---T---L-
I
__,-_-
I
I
,---
\ I
;--
;--a;--
-,---:---’
I
-170
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
Load (MN)
Figure 6.6: Predicted Stiffness on 1.0-m Footing Before Load Test
78
Load Settlement Curve - 1.5 M Footing
Average 30 Minute Monotonic Curve
0
I
j Wk
PredictedI( Set#i
_II
II
L-v- II
I ---I
I
’ --WAJHredictedK,Set#2
---
-10
-20
-30
-40
-50
--------7--------
I
I
I
_,
---‘T
,
/
----,-
---
/
_/__
I
--T----,-----
I
I
/
I
I
I
I
I
I
I
I
I
2
I
I
-60
I
I
I
I
I\
I
I
I
I
I
I
-70
-80
-90
-100
-110
--
-~----~----L---d----I----L----~----C---I
I
I
I
I
I
I
\i
-120
-130
-140
-150
-160
Figure 6.7: Predicted Stiffness on 1.5-m Footing Before Load Test
79
i
Load Settlement Curve - 2.5 M Footing
Average 30 Minute Monotonic Curve
0
-10
-20
-30
-40
0
I---/
i ____ /____ t--WAKPredictedK,Set#2
\
r----l----
1
2
3
4
5
6
7
8
9
Load (MN)
Figure 6.8: Predicted Stiffness on 2.5-m Footing Before Load Test
80
IO
Load Settlement Curve - 3.0 M Footing
Average 30 Minute Monotonic Curve
NORTH
I
I
---_
I
I
I
I
I
I
;---;--l---;----
cted K, Set #l
-30
-
-
_;_
-
-
I
I
40,
--
-
-
I
-
-
_I_
-
-
I
I
I
I--I
I
J---L---L---I
I
I
~---~~~~---~---~---~--I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I----1---_1--I
I
I
-60
----------?---T---T---‘---
I
I
I
-70
---
-4;
_-I__-J_‘__l___L---I--’
\i
I
I
I
I:
I
\
‘\>
-- -,-I - - -,_ - - ~---1---:.---I---~,‘-.Set#2
-50
8
-I-
I
-,_
I
L---L---I
I
I
I
I
T--I
I
I
I
I
I-------,-------T-I
I
I
I
I
I
_,‘4
I
____
I
I
I_-_
/
WAK PredictedK,
I
-?---~---r-’
I
I
- I-
I
!
I
I
I
I
-
-
---l---L---C--
k
I\
-100
-110 c
-120 I-
--
I
I
-I-
I
-130
-
I
I
-II
-
-
/
I
-l--I
I
I
I
I
I
I
I
)
I
I
I
\’
r-----! ’
_i
I
~---i----~---l---:---~---~----~---J..._~---~--_I__-~
I
I
I
I\
I
-140 ~---~----------t---:---~----~----t---~---~,,,---~----~
-150 i---l----i---~---i---~---i
0
1
2
3
4
‘h___,____
I
__-_ i--+-;-+
5
6
7
8
9
10
1112
L-mw
Figure 6.9: Predicted Stiffness on 3.0-m North Footing Before Load Test
81
Load Settlement Curve - 3.0 M Footing
Average
30 Minute Monotonic
Curve
SOUTH
0
-10
-20
---
-30
-,----+--
_-,----
:----
40
-50
----;----
-60
0
I
I
I
---l--‘-T----,----T----,--7----~----~---~----~---
I
I
I
I
I
_-_-----1
I
I
I
I
I
I
---
_I---I
I
I
L----l----l--
----I----
I
-------_
I
I
-
-
-
AI
-
-
-
I
I
;
_‘_-_-_--_--------_
i--I
I
I
I
_,___
-:----,----T
I
I
I
I
I--I
_‘_
I
-
-I
;
I
I
I
I
--I----1----I
I
i---I
I
-
ii;
I
I
\I
b
I
I
-
- _I_
I
-
-
I--I
-
L--+--
I
I
-I-
I
----i----L---
I
--------
I
I
-
;
-L---
a
I\
-
-
_ i
’
-
I
.i
7
8
-
-
I- 1
-
-
i
0
1
2
3
4
5
6
9
Load (MN)
Figure 6.10: Predicted Stiffness on 3.0-m South Footing Before Load Test
82
10
7. ANALYSIS
7.1
OF THE DATA
SCALE EFFECT
This part of the project is detailed in Ballouz, Maxwell and Briaud (1995).
The scaleeffect on bearing capacity hasbeen acknowledgedfor spreadfootings on sand.
If bearing capacity is defined as the pressurereachedfor a displacementof 150 mm, the scale
effect is obvious (Figure 7.1); indeed the larger the footing, the smaller the pressurethat can be
applied before reaching a given settlement. In Figure 7.2, this is illustrated by the curve with solid
dots, which shows the classicalshape(Meyerhof, 1983).
Now let us imagine that one is performing a l-m diameter and a 3-m diameter triaxial test
where the top platen is a spreadfooting (Figure 7.3) while the confining pressureand the sand
used are the same. One would expect to obtain the samestress-straincurve for both tests
regardlessof the scale. Therefore one would expect in either casethe samestressfor the same
strain. However, if one was to plot the stress-displacementcurves,different curveswould be
obtained and the stressread at the samedisplacementwould dependon the size of the footing and
would be lower for the larger footing.
This was the clue which led to comparing the bearing capacity at the samerelative s/B, a
measureof the averagestrain below the footing. If the bearing capacity is deftned at a settlement
over width (s/B) ratio equal to 0.05 the scaleeffect disappears(Figure 7.2). In fact, if the load
settlement curves are plotted as pressurevs settlement/width, the plots almost convergeto a
unique curve (Figure 7.4). This proves that there is no scaleeffect if the load tests results are
plotted as “stress-strain”curves.
A literature searchconducted after this finding led to a discussionby Osterberg(1947)
who presentedload-settlement curvesfor plate tests of varying diameters(0.25, 0.5, 0.75, 1 m)
on clay. Osterberg shows that if the data is plotted as pressureversussettlementover diameter,
the load-settlement curves for the three largest plates collapseinto one curve while the loadsettlementcurve for the 0.25-m plate remainssomewhatstiffer. Palmer (1947) also presentsthe
83
“0
40
20
80
60
Settlement
100
120
140
(mm)
Figure 7.1: Pressurevs. Settlement Curves
1.0 -
@yy--
x
g 0.8 2%
2 0.6 x
Scale Effect Eliminated
0
-+--
/
\
0
-, Scale effect
present
-*\
p(B) at S=150mm
or-i-
l
0.2 e-
o p(B) at S=0.056
I”‘11111
OO
0
--- 0
t,,,,,,
1
Footing
2
Width,
3
B (MI
Figure 7.2: ScaleEffect at Large Displacement
84
1
4
Different
?@@
CT
li
Same
for all
cT vs 8 = Scale Effect
cr vs E - No Scale Effect
Figure 7.3: Triaxial Test/SpreadFootingAnalogy
1.8
1.5
z
g
I2
z 0.9
z
ii:g 0.6
0.3
o’l”“““““““‘ll
0
0.02
0.04
0.08
0.06
Settlement/Width,
S/B
Figure 7.4: Pressurevs. Settlement/Width Curves
85
0.10
load-settlement curvesfor three plateswith varying diameters(0.38, 0.61,0.76 m) on a pavement.
If those curves are plotted as pressureversussettlementover diameter, they collapseinto one
unique curve. Burmister (1947) goes on to propose a method to obtain the load-settlement curve
for a footing from a triaxial stress-straincurve. Skempton (195 1) dealing with spreadfootings on
clay also proposed a method to obtain the load settlementcurve from triaxial test results and
showed, using linear elasticity, that the averagevertical strain under the footing is equal to s/2B.
If the triaxial test analogy of Figure 7.3 points in the direction of the uniquenessof the p
vs s/B curve, one factor points in the other direction; the depth of influence of a small footing is
much shallower than the depth of influence of a large footing. Sincethe stiffnessof a sandis
dependenton the mean stresslevel the large footing should exhibit a somewhat stiffer p vs s/B
curve than the small footing. For the footings tested, this does not seemto be a major factor.
Note that if bearing capacity is defined as the pressurefor an s/B ratio of 0.1 (1.5 MPa on
Figure 7.4) and if a factor of safety of 3 is applied to obtain a safepressure(0.5 MPa), then the
safepressurecorrespondsto an s/B ratio equal to 0.007. For all the footings in this study, this
leadsto a settlement smaller than 25 mm. Therefore, for those five footings the bearing capacity
criterion would control the design, not the settlementcriterion. This is contrary to common belief
for footings on sandbut is due to the definition used for the bearing capacity (s/B = 0.1) rather
than plunging failure,
If the p vs s/B curve is unique for a given deposit then the bearing capacity pUis
independentof the footing width. For footings at the surfaceof a sand,the generalbearing
capacity equation gives:
P, = $YBN~
(1)
where y is the unit weight and NY, a parameterdependingonly on the sand strength. If
112yBNy is a constant independentof B, then NY, cannot be a constant and must carry a scale
effect in l/B similar to the classictrend on Figure 7.2. This major shortcoming plus the difficulty
in obtaining an accuratevalue of the neededsoil parameter $ and the documentedpoor accuracy
86
of this method (Amar et al. 1984) lead to the recommendationthat the use of this equation should
be discontinued. A doubt can be cast on the above recommendationif it is argued that equation
11 gives a pressurewhich correspondsto plunging failure and not to s/B = 0.1, and that the loadsettlement curvescould diverge past s/B = 0.1 (end of the experimentaldata) to reestablishthe
validity of the P, equation describedabove.
By comparing the bearing capacity value pU,read at an s/B ratio equal to 0.1 with the SPT
blow count N and CPT point resistanceqa taken as averageswithin the zone of influence of the
footings, it appearsthat the following rules of thumb are reasonablefor the medium densesandat
this site:
Pu = 2 with N in blows/O.3m and pUin Mpa
(2)
pLl =4c
4
(3)
One can also give the following approximations for the pressurepa which leads to an s/B ratio
equal to 0.01:
Pa = $ with N in blows/0.3-m and P, in Mpa
(4)
pa =9c
12
(5)
Another acknowledged scaleeffect phenomenonexists at the settlementlevel. Terzaghi and Peck
(1967) and NAVFAC (1982) give the following relationship:
B+0.3 2
kB = k(0.3 m) 2~
I 1
87
(6)
where kB and k(u.3 m) are the moduli of subgradereaction for footings of diameter B (in meters)
and 0.3 m respectively. The parameterkB is defined as the pressureon the footing divided by the
settlement of the footing under that pressure;the unit is
, The valuesof kB can be
calculated for a given settlement(25 mm) for the five footings tested. Figure 7.5 shows that in
this casethere is a scaleeffect and that this scaleeffect is well representedby the function
[(B+0.3)/(2B)12.
If however, the valuesof kB are comparedat the sames/B or better if a new
parametere is defined as
e=-
P
s/B
(7)
and if the e values are compared for the same s/B, then the scale effect disappears. In fact, e is
closely related to the soil modulus, E. Indeed in elasticity:
e,P=
s’B
E
I[1 - U2)
(8)
Therefore, for squarefootings, e is independentof B while k is dependenton B. The use of k
should be discontinued becauseit inducesan unnecessarydifficulty and e, a true modulus of
subgradereaction should be used in its place becauseit essentiallyrepresentsa soil property.
These observationsand Figure 7.4 point in the direction of the uniquenessof the p vs. s/B
curve for a given sanddeposit, If this finding is corroborated by future researchit will greatly
simplify the prediction of spreadfooting behavior,
If one recalls the heterogeneityof the sanddeposit as shown by the CPT soundings
(Figure 4.8), it may be surprising to seehow well behavedthe pressureversusrelative settlement
curves are for the 5 footings (Figure 4.12). In fact the heterogeneitydecreaseswhen going from
the CPT (Figure 4.8) to the SPT (Figure 4.7), to the PMT (Figure 4.9), and to the footings
(Figure 4.12). This is attributed to the gradual increasein scaleand in the volume of soil tested
88
1.0 0.8 0.6 0.4 l
0.2 -
k(B) at S- 25mm
o e( 8) at S- O.OlB
Footing Width, B (ml
Figure 7.5: ScaleEfbt
on Modulus of SubgradeReaction
from one type of test to the next. This tends to show that a sanddeposit which is apparently very
heterogeneousat the scaleof the CPT point (36 mm) may be quite homogeneousat the scaleof a
spreadfooting (3000 mm). The implication is that reasonablyaccuratepredictions should be
possible even for apparently heterogeneousdeposits,that differential settlement between adjacent
footings may not be as large as calculated on the basisof separateborings, and that the test which
involves the largest soil volume has an advantage.
7.2
CREEP SETTLEMENT
This part of the project is detailed in Gibbensand Briaud (1995).
Section 4.3 describesthe load test results including the creep curves. The model proposed
by Briaud and Garland (1985) hasbeen used for many yearsto predict the time dependent
behavior of soils. This model is:
Sl
-=
s2
c)
It1
t2
n
89
(9)
where, sl is the settlementafter a time tI, s2 the settlementafter a time t2, and n is the viscous
exponent which is a property of the soil.
Since the time dependentproblem is a creep problem in this case,n will be called the creep
exponent. In order to find n, the data is plotted as log 3 versuslog -t1 and a straight line
s2
t2
regressionis performed through the points. The slope of that line is n. Typically n valuesfor
working stresslevels range from 0.005 to 0.03 for sandsand 0.02 to 0.08 for clays.
How well the straight line fits the data points is a measureof how appropriate the model
is. As can be seenfrom Figures 4.13 through 4.16, the straight line fits quite well for both the 30min long stepsas well as the 24-h long steps. Therefore the first observationfrom those creep
tests is that the Briaud-Garland model works well in describingthe data up to 24 h. If it is
assumedthat the model is also applicablefrom 24 h to 50 years,the settlementat 50 years can be
compared to the settlement at 24 h as follows:
n
For a value of n equal to 0.03 the ratio of SJOyearsto ~24hoWswould be 1.34 and the settlement
at 50 years would be 34% larger than the settlementat 24 h. If the referencewas the settlement
at 1-min instead of 24 h then the above ratio would be 1.67 meaningthat the settlement at 50
years would be 67% larger than the settlementat 1 min. Theseexamplesgive an idea of the
magnitude of the creep settlementthat one can expect for footings on sandswithin the working
stressrange.
Figure 7.6 shows the variation of n with the stresslevel under the footing. The n values
are obtained as describedabove and the stresslevel is characterizedby the ratio of the load Q
over the ultimate load QUdefined as the load reachedfor a settlementequal to 0.1 times the
footing width. Figure 7.6 correspondsto all the measurementsmade on one footing during that
load test. As can be seen,the n valuesincreasewith Q/Q, during the first monotonic loading,
90
Creep Exponent Curve
3.0 M Footing
NORTH
60
56
52
48
44
40
36
c
8 32
74
wE: 28
24
20
16
12
8
4
0
0
10 20 30 40 50 60 70 80 90 100110120130140
Q/Qu (o/o)
Figure 7.6: Creep Exponent Curve for 3.0-m North Footing - QU= 12.50~MN
91
Then there is a suddendrop in the n value aRerthe first unload reload cycle followed by an
increaseof n with Q/QU, This secondincreasehowever is along a different line from the first
monotonic loading. This phenomenonis observedagain for the third and fourth loadings.
Therefore the secondobservationfrom the creep measurementsis that cyclic loading influences
significantly the rate and magnitude of the creep settlement, Each new cycle decreasesthe
amount of creep settlement. This observationis basedmostly on 30-min load stepsand one
wonders if it would hold true if the load were held for much longer periods of time.
It was also observedthat if a load Ql is held for 24 h and then the load is decreasedto 42
where it is held for a new 24 h, the creep under 42 is very small comparedto the creep under Q 1.
This supports the idea that preconsolidation decreasescreep settlement. It would be interesting to
seeif the creep settlementcontinuesto be small when the load Q2 hasbeen held for more than 24
h.
Overall the n valuesobtained from the spreadfooting tests ranged from 0.008 to 0.054
and averaged0.028. Creep pressuremetertests were performed at the site close to the footings.
During those preboring tests the pressurewas held for 10 min at a point on the pressuremeter
curve close to the end of the straight line. Exponents n were obtained in a fashion identical to the
one used for the spreadfooting tests. The pressuremeterexponentsranged from 0.007 to 0.025
and averaged0.014. Therefore until further theoretical or experimentalunderstandingof the
reasonfor the difference between the spreadfooting exponentsand the pressuremeterexponents
it is recommendedto use:
nfooting = 2npmt
7.3
STRAIN VERSUS DEPTH
This part of the project is detailed in Gibbensand Briaud (1995).
Section 4.3 gives the results of the telltale measurements.Figure 4.19 representsthe
normalized settlement s/stopplotted againstnormalized depth Z/B for the 3.0 m South footing.
92
The parameter s is the downward movement of a point at a depth Z in the soil. The parameter
stopis the settlement of the footing and B is the footing width. An s/stopvs. Z/B curve is plotted
for severalstopvalues calculatedusing varying percentagesof B. The normalized plot makesit
possibleto show the results for all loads and all footings on the sameplot and therefore to draw
general conclusions.
The first observationfrom those plots is that the settlementof the soil at a depth of 2B
below the footings ranged from 0% to 10% of the settlementat the surfaceand averaged3.2%.
Therefore about 97% of the settlementtakes place within a depth of 2B below the footing and it
is appropriate to use a 2B depth of influence for calculating the settlementof squarefootings on
sand. Furthermore the settlementat a depth of 1B below the footing ranged from 11% to 30% of
the settlement at the surfaceand averaged22%. Therefore 78% of the settlement occurs within a
depth of 1B below the footing and therefore it is very important to obtain the compressibility
properties of the soil within that zone. Similarly the settlementat a depth of 0.5B ranged from
47% to 7 1% and averaged64%.
The secondobservationrelatesto the use of the parameters/B instead of s in the
presentationof load test results, Since 97% of the settlementoccurs within 2B below the footing,
the averagestrain in the soil within that zone is approximately s/2B. This confirms the theoretical
result of Skempton (1951). It also shows that s/B is related to the averagestrain under the
footing. Since the pressurep under the footing is related to the averagevertical normal stress
under the footing, the plot of p vs. s/B is directly related to the averagestressversusaverage
strain curve for the soil massunder the footing. Therefore this is a superior way of presentingthe
results of a spreadfooting load test comparedto presentinga load-settlementcurve.
The third observation dealswith the evolution of the settlementversusdepth profile as the
load increasesduring the load test or as the footing size increasesfrom one load test to the next.
One might think for examplethat as the load on the footing increasesthe depth of influence
increasesor decreases.The data show that the depth of influence remainsremarkably constant.
Indeed no particular trend can be observedin the evolution of s/st,p at 2B as the load increasesor
as the width of the footing increases,
93
These numberscan be used to preparea strain versusdepth profile. The strain in a layer is
given by
a(at z+Az/ 2) =
s(at z) - s(at z+Az)
AZ
where z is the depth below the footing bottom to the top of the layer, AZ is the thickness of the
layer, slatz) is the settlement at the depth Z.
K
s(atz ) = azstop
and
AZ = PzB
where stopis the settlement of the footing then,
8op
PZB
or,
a(at z+Az/2) =
stop
a,--a ( z+Az )I--- B
PZ
versus 2 For examplefor Z = 0 and AZ = 0.5B,
B
the valuesof a, and o(,+A,)
are obtained from the results mentionedin the previous
B
=0.72.
paragraph. In this case a(,=~) = 1 and ~l(~=05B) = 0.64, therefore e(at 0 25~) stop
Figure 7.7 shows a natural decreasein strain with depth except close to the bottom of the footing
94
0.0
-0.5
8 -1 .o
-1.5
-2.0
0.50
(E)(B/ stop)
Figure 7.7: Lateral Strain Versus Vertical Strain
paragraph. In this case a(,,O)
B
= 0.72.
= 1 and c’(z=0.5B) = 0.64, therefore s(at 0.25~) stop
Figure 7.7 shows a natural decreasein strain with depth except close to the bottom of the footing
where the strain decreasesdue to the lateral confinement brought about by the roughnessof the
footing.
7.4
SOIL MASS DEFORMATION
This part of the project is detailed in Gibbens and Briaud (1995).
Section 4.3 describes the results of the inclinometer measurements. Figures 4.17 and
4.18 representthe lateral deflections of the casing as a function of depth.
The first observation is the general shapeof those curves which indicate a lateral bulging
of the soil reaching a maximum at a depth which ranged from 0.4B to 1.25B and averaged0.73B.
Note that this depth of maximum lateral strain correspondsquite well to the depth of maximum
95
the deformation pattern in the soil massunder the footing correspondsquite well to a cylindrical
cavity expansion, This observationis not consistentwith the assumptionof a single shearslip
surfaceanalysiswhich is the basisof the classicalbearing capacity equation.
The secondobservation dealswith the magnitude of the horizontal displacementat the
edge of the footing compared to the magnitude of the vertical displacementof the footing. Figure
7.8 shows the relationship between the ratio 61,(max)/6v
as a function of H./B. The parameter6, is
the settlementof the footing under a given load Q, Sl,(nnix)is the maximum horizontal movement
measuredby the inclinometer under the sameload Q, H is the distancebetween the inclinometer
casingand the footing edge and B is the footing width. Figure 7.8 indicates that at the footing
edge the maximum horizontal movement is of the order of 15% of the footing settlementand that
the horizontal zone of influence extendsto about 1.8B on each side of the footing. This means
that settlementbeamsshould be at least 5B long to provide a good measurementof the absolute
footing settlement,
The third observationdealswith the volume changein the soil. Indeed the inclinometer
results make it possibleto estimatethe volume changeof the soil massbelow the footing. Figure
2.308.
-\
Figure 7.8: Comparison of the Horizontal and Vertical Soil Movement
96
7.9 is a schematicof the soil massinfluenced by the footing. The changein volume imposed by
the penetration of the footing is (ABCD on Figure 7.9):
The changein volume of the soil masscorrespondingto the B2 area and to the depth of influence
2.33B can be estimatedas follows. The initial volum is (CEFD on Figure 7.9):
(B2)(2.33B) = 2.33B3
The deformed volume is approximatedby:
This assumesthat the deformed volume CIEFND on Figure 7.9 can be approximated by GOPH
where JK is equal to MK with IK = 8h(max),Note also that the profile DNF is an approximation
of the shapeof the inclinometer profiles suchas the one of Figure 4.17. From Figure 7.8, the
value of 6h(max)at the edge of the footing is taken as 0.156,. Therefore the volume changeof the
soil massCEFD (Figure 7.9) is:
AVsoil = F(2)
+ B’) (2.33B) - 2.33B3
or,
AVscil = 2.33B[(O.l58v +B)2 -B”)
97
BxB
Iu
nvsoil
K
Figure 7.9: Schematicof the Volume ChangeUnder the Footing
98
Since 0.156,
is very small compared to B,
[B” +2(0.15S,B)]
(0.15sv + B)’
is approximated by
then,
AVsoil = 2.33B(0.36vB)
and the ratio AVsoil is.
AVfooting ’
AVsoil
= (2*33)0.36vB2 = o 7
AVfooting
6,B2
’
Therefore the changein soil volume is smaller than the changeof volume imposed by the footing
and the soil compressesduring the load test. While a number of approximations were used to
calculate the ratio AVsoillAVfooungthe result tends to show that there is no dilation and instead
compressionof the sandduring loading.
99
8.
8.1
NEW LOAD SETTLEMENT CURVE METHOD
THE IDEA
This part of the project is detailed in Jeanjeanand Briaud (1994).
The idea is to develop a method to predict the complete load settlementcurve for spread
footings, For piles subjectedto axial monotonic loading this problem was solved by Seedand
Reese(1957) and led to the t-z curve concept for axially loaded piles. The idea is to do for
spreadfootings what was done for piles a long time ago.
There are severalapproachesto solving a geotechnicalproblem. One is the fundamental
approachwhere the soil is modeled by discrete elementsand the continuum behavior is
theoretically assembled:this is the caseof the finite elementmethod. One is the empirical
approachwhere a correlation is usedbetween a test result and the parameterto be predicted: this
is the caseof Peck et al.‘s method (1974) for predicting the pressurecorrespondingto 25 mm of
settlement for footings on sandon the basisof SPT blow counts. Another method which fits
possibly between those two approachesis the approachby analogy where the soil test which is
performed closely resemblesthe loading imposed on the soil by the foundation and where the
remaining difference is bridged by using theoretically and experimentallybasedcorrections: this is
the caseof the cone penetrometermethod usedto predict the axial capacity of a pile or the
pressuremetermethod used to predict the behavior of a horizontally loaded pile.
In the long run the fundamental approach will be the method of choice. At present
however, the complexity of the modeling process and the inability to assessthe many required
parametersreliably and economically prevent this approachfrom being a routine design approach.
The method by analogy was chosento develop the new load settlementcurve method.
100
8.2
DEVELOPMENT OF THE METHOD
The inclinometer measurementsshown in section 7.4 indicate that the penetration of a
footing into a sanddeposit can be consideredas a cavity expansionphenomenon. Therefore a
cavity expansiontest would make sensefor the approachby analogy. Sincethe complete load
settlement curve is desired,this cavity expansiontest should give a complete pressuredeformation curve. This led to the choice of the pressuremetertest (PMT) for the method by
analogy. The concept is then to perform pressuremetertests within the zone of influence of the
spreadfooting, generatean averagePMT curve by using an influence factor distribution for a
weighted averageof the individual curves,and transform the averagePMT curve into a spread
footing curve by using a correction factor obtained from theoretical and experimental
considerations,
It is recommendedthat pressuremetertests be performed at 0.5B, 1B and 2B below the
footing level where B is the footing width. Each test leadsto a pressurep versusrelative increase
in probe radius ARp/Rp as shown on Figure 8.1 where Rp is the radius of the deflated probe and
ARp the increasein probe radius. Each curve is then adjustedfor the size of the borehole (Figure
8.1) by extending the straight line part of the PMT curve to P = 0, shifting the vertical axis to that
new origin and calculating the relative increasein cavity radius (AR&)
&P
--AR, _ RP
R,
as:
ARP
[ RP 1c
I1
(1)
l+ ~ARP
Rp c
where & is the initial radius of the borehole (cavity), AR, the increasein cavity radius, and
(ARP/Rp)cthe value of the relative increasein probe radius correspondingto the initial radius of
the cavity.
The corrected curves(p vs ARJRc) obtained at the testing depths below the footing are
101
0.10
(ARp /Rp )c A
0.15 0.20 0.25 0.30
lI,
0
aRp /Rp
ARc/Rc
0.05
0.10
0.15 0.20
Figure 8.1: PressuremeterCurve (PMT 1, z = 0.6-m)
then averagedinto a single curve called the averagePMT curve on the basis of a stressinfluence
factor I similar to the one proposedby Schmertmann(1970). This factor is defined as:
I=Aol-*o3
(2)
*P
where Aol and A03 are the increasein major and minor principal stressrespectively at a depth z
below the footing,when the footing is loaded with a pressureAp. A three dimensionalnon-linear
finite element simulation was performed. The results are shown on Figure 8.2. These profiles
appearto be relatively independentof the pressurelevel on the footing and of the sanddensity.
Therefore, a unique simplified diagram is used (Figure 8.3).
For any value of A&L&, the pressurespi for eachof the pressuremetercurveswithin the
depth of influence are averagedas follows to give the pressurep on the averagePMT curve
102
Range for Various
Footing Load Levels
0'
0.2
Influence
0.4
Factor
0.6
0.6
Au, -Au3
I =
OP
Figure 8.2: InfluenceFactorDistributionwith Depth
Example of
Depth of
PM? Tests
x Z3=28
A = Total
0
0.1
Influence
0.2
0.3
0.4
Factor
I =
Area
0.5
Au1
0.6
0.7
- A43
AP
Figure 8.3: Recommended
InfluenceFactorDistribution,andExampleof the Determinationof
the ai Factors
103
correspondingto this AR&:
P = +CPiai
where ai is the tributary areaunder the influence diagram for the PMT test at depth Zi; and A is
the total area under the diagram (A = 1,125). In order to obtain the al values,the depths at which
the PMT tests were performed are identified, then boundariesare establishedat mid-height
between two consecutivePMT test depths, and ai valuesare calculatedas the areasbetween the
boundaries(Figure 8.3). This processleadsto the averagePMT curve for that footing (Figures
8.4 and 8.5).
In order to transform the averagePMT curve into the footing curve, the following was
considered. First, the PMT limit pressurewhich is found at A&&
= 42% is generally associated
with the bearing capacity of the footing p,, defined here as the footing pressurereachedat a
settlement over width ratio (s/B) equal to 10%. In order for those two points to match, the
AR&Q axis is transformed into a (A&/4.2&)
axis. Second,a three dimensionalnonlinear finite
element simulation of the footing and of PMT tests at 0.5B, 1B and 2B was performed for two
sanddensities(D, = 55% and 95%). For the pressuremetertests, both the preboring and
selfboring tests were simulated. The meshwas first validated againstthe elastic theory, then the
geostatic stresseswere turned on in the whole mass. For the selfboring test the geostatic stresses
which would have existed againstthe borehole wall had the borehole not been drilled were applied
againstthe borehole wall (this step was bypassedfor the simulation of the preboring test). Then
the pressureexerted by the pressuremeterprobe was applied in incrementson the borehole wall.
This allowed to generatethe PMT curvesas p versus(A&/4.2&)
mentioned above at the depths
0.5B, lB, and 2B below the 3- by 3-m footing. The weighted averageof thesethree curveswas
determined using the influence factor processdescribedearlier The weighted averagePMT
curves for both pressuremetertypes are shown on Figures 8.4 and 8.5 together with the 3- by 3-m
104
2
500
,
I
3m x 3m Footing
0
0.02
0.04
(ARC /4.2Rc
0.06
0.08
0.10
1 and (S/B)
Figure 8.4: FEM Resultsfor the Medium DenseSand
_ 3mx
0
3m Footing
0.02 0.04
(ARc/4.2Rc)
0.06
0.08
and (S/B)
Figure 8.5: FEM Resultsfor the DenseSand
105
0.10
footing pressureversusrelative settlementcurve. Thesecurvesallowed to develop the
transformation function I to go from the weighted averagePMT curve to the footing pressure
vs. relative settlement curve.
The transformation is performed by using the function I as follows for eachpoint on the
averagePMT curve:
S
-- ARC
ii - 4.2R,
Pfooting = T(P Pmt )
(5)
where s is the footing settlement,B the footing width, (AR&Q and ppmtcorrespondto a point
on the averagePMT curve, pfootingis the pressureon the footing correspondingto s/B, and I
the transformation function which dependson s/B. The function I was obtained from the finite
element simulation by taking the ratio of pfeeting/ppmtfor a given s/B (Figures 8.4 and 8.5). The
results are shown on Figure 8.6 for the preboring pressuremeterand for the medium denseand
densesand.
At the limit pressurewhere (A&/4.2&)
and s/B are equal to 0.1, it is known from footing
load tests (Briaud 1992) that for sand,the I factor is about 1.4 as shown on Figure 8.6 for
relative embedments(D/B) between 0.25 and 0.75. Indeed in this casethe I factor is the bearing
capacity factor k used in the design of spreadfootings basedon pressuremeterdata. This is lower
than the FEM r value which is about 2. Furthermore, the results of the full-scale load tests
allowed to generatethe experimental I valuesshown on Figure 8.6 for the 3 m footing and the
l-m footing. The FEM results,the till-scale tests performed in this study, and the previous
experimental data at s/B = 0.1 led to the choice of a recommendedconservativefimction I (solid
line on Figure 8.6).
In order to predict the settlement as a function of time for a given pressure, the model
106
FEM. Dense Sand
Med. Dense Sand
FEM.
Experimental
1*
I
0
I
I
I
I
I
0.04
0.02
Observations
0.06
ARC /4.2Rc
I
I
.
0.08
0.10
or S/B
Figure 8.6: The Correction Function I?(s/B)
proposedby Briaud (1992) is used
St =
(6)
S(1 ,in)[&]n(footing’
where st is the settlementafter a time t in minutes, ~(1rlrin)is the settlementpredicted by the
is related to the value of npmtobtained from a creep step towards
proposed method, and nfooting
the end of the linear phasein the pressuremetertest; the pressureis held constant and the relative
increasein radius is recorded as a f-unctionof time (Briaud 1992). The modulus is then plotted as
shown on Figure 8.7 and the values of the time exponent nlllt are given by the slopesof those
lines. The relationship between nfooringand npllltis given by the results of section 7.2:
nfooting = 2npmt
107
Figure 8.7: PressuremeterModulus as a Function of Time
8.3
STEP BY STEP PROCEDURE
1.
Estimate the required width B of the footing.
2
Perform preboring, pressuremetertests at 0.5B, 1B and 2B below the footing base. This
method is basedon the use of the TEXAM pressuremeter.During those tests expandthe
probe as much as possible.
3.
Correct the PMT curvesto pressureon the cavity wall p versusrelative increaseof the
cavity radius (AR,&) by making use of Eq. (1).
4.
Selectthe PMT curvesrelevant to the problem within the 3B depth of influence and
generatea profile of curvesfor the footing location.
5.
For this footing the PMT curvesare averagedaccording to the influence factor
distribution (Figure 8.3, Eq: (3) and Figure 8.8). This leadsto the weighted averagePMT
curve for this footing giving pPlllrvs (AR&J.
10s
The weighted averagePMT curve is then transformed into the footing curve pfoot vs s/B
6.
by using Eqs. (4) and (5). The function IY recommendedon Figure 8.6 is the one used for
the prediction.
The time rate of settlementis then estimatedby using the power law model proposed in
7.
JR. (6).
As an example,the step by step procedurewas followed forthe l-m and 3-m footings
listed at the site. Figure 8.1 is an exampleof the TEXAM PMT tests performed and of the results
obtained after step 3. More details about steps 1,2 and 3 can be found in Briaud (1992). Figure
8.8 is the averagePMT curve obtained after steps4 and 5. Figure 8.9 shows the transformation
from the weighted averagePMT curve to this footing load settlementcurve. Figure 8.10 is a
comparisonbetween the predicted and the measuredload settlementcurvesfor the l-m and 3-m
footings.
Average PMT Curve
for Im Footing
2
a
Y
Y
*
M-1
1
.PMT.Zl
-0
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
l
PMT.Z 2
l
PMT.Z
3
0.18
0.20
ARc/Rc
Figure 8.8: Generatingthe Average PMT Curve for a Footing
109
{
1.5 -
Predicted
Curve
for 3m Footing
Predicted
II
0
I
I
0.02
I
I
Curve
for Im Footing
Average
PMT
Curve
for lm Footing
Average
PMT
Curve
for 3m Footing
I
I
,I
I
II
I
I
III
I
0.04
0.06
0.08
Settlement/Width,
S/B
L
0.10
Figure 8.9: Predicted Footing Responseby ProposedPMT Method
Load
0
0.4
0.8
(MN)
1.2 1.6
2.0
o0
Load (MN)
2.5 5.0 7.5 10.0
10.012.5
12.5
125-
Figure 8.10: Measured Versus PMT Predicted Load Settlement Curves
110
9.
CONCLUSIONS
The following outlines the conclusionswhich were drawn from the 5 tasks describedin
this report:
1.
A spreadfooting data basehasbeen developed. This data basecomesin the form of an
IBM PC compatible computer program called SHALDB. The program is in two parts: an
organized set of data files follows the DBASE format and a program to manipulatethese
data written in Visual Basic. SHALDB version no. 4 is the version prepared as an
outcome of this project. Version nos. 1 to 3 were also developedat Texas A&M
University from which version no. 4 is available. SHALDB contains at the presenttime 77
casehistories where the behavior of spreadfootings is documented. Some of the case
histories are of the load test type where a complete load settlementcurve was recorded;
some of the casehistories are of the performancemonitoring type where the settlement
versustime was recorded for the given structural load. With the program one can retrieve
the data, inspect it, create a sub data basesatisfying chosencriteria, compare the
measurementswith predictions and so on.
2.
Load tests were performed on five squarefootings ranging in size from 1 m to 3 m. They
were all embedded0.76 m. The load settlementcurve was recorded for all footings which
were pushedup to 150 mm of penetration. During the tests the deformation of the soil at
depth in the vertical direction was measuredwith telltales at OSB, 1B and 2B depths. At
the sametime the deformation of the soil at depth in the horizontal direction was
measuredwith inclinometers at various distancesfrom the footing edge. One of the major
lessonslearned from the instrumentationis that settlementbeamsfor large footing tests
may be unreliable and that the best way to measuresettlementis to place a telltale through
the footing near its center and anchoredat a depth of 4B. A very inexpensivetelltale
systemwas developed.
111
3.
A very successfulprediction event was organized. A total of 3 1 predictions were received
from 8 different countries, half from consultants,half from academics. The load creating
25 mm of settlement 425 was under estimatedby 27% on the average. The predictions
were 80% of the time on the safeside. The load creating 150 mm of settlement Ql50
was
underestimatedby 6% on the average. The predictions were 63% of the time on the safe
side. The scaleeffect was not properly predicted and there was a trend towards
overpredicting
Ql50
for the larger footings, The most used methods were basedon the
CPT, SPT and PMT in that order. The averagetrue factor of safety was 5.4. Therefore it
appearsthat our profession knows how to design spreadfootings very safely but could
design them more economically.
4.
An independantset of predictions were performed on the 5 load tested footings using 12
settlement calculation methods and 6 bearing capacity calculation methods. The best
settlement methods were the SchmertmannDMT (1986) and the Peck & Bazarra (1967)
although they are somewhat on the unconservativeside. The best conservativemethods
are Briaud (1992) and Burland & Burbidge (1984). The best method for bearing capacity
was the simple 0.2q, method from Briaud (1993a). Most other methods were 25 to 42
percent conservative.
5.
WAK
tests were performed on the five footings before load testing them. This
sledgehammerimpact test allowed to obtain the static stiffnessof the soil-footing
assembly. The stiffnesspredicted by the WAK test was comparedto the stiffness
measuredat small displacementsin the load tests, The comparison shows that the WAK
test predicted a secantstiffnesswhich correspondsto a settlementaveragingabout 10 mm.
6.
The medium densesandhad a mean SPT blow count of 20 blows/O.3m, a mean CPT qc
of 7 MPa, a meanPMT limit pressureand modulus of 800 kPa and 8 MPa respectively,a
mean fiction angle of 32’, and a meancross hole shearwave velocity of 270 m/s. In this
sandthe loads necessaryto reach 150 mm of penetration were 1740 kN, 3400 kN, 7100
kN, and 9625 kN for the 1 m, 1.5 m, 2.5 m and 3 m footings respectively. In this sandthe
load necessaryto reach 25 mm of penetration were 850 kN, 1500 kN, 3600 kN, and 4850
kN for the 1 m, 1.5 m, 2.5 m and 3 m footings respectively,
112
7.
The scaleeffect was studied. It was found that for the five footings tested there was no
scaleeffect; indeed when plotting the load-settlementcurvesas pressurevs. settlement
over width curves, all such curvesvanishto one curve and the scaleeffect disappears.
This is explainedby the uniquenessof the soil stressstrain curve. Since the general
bearing capacity equation shows a definite scaleeffect, the use of this equation is not
recommended. The pressurepUcorrespondingto an s/B ratio equal to 0.1 can be
estimatedas follows:
pu=z
Pu =-
N
with N in blows/O.3m and pu in MPa
qc
(1)
(2)
4
The pressure pa corresponding to an s/B ratio equal to 0.01 allowable pressure can be
estimated as follows:
N
Pa =z
with N in blows/O.3m and pa in MPa
Another finding related to scalewas that a sanddeposit which is apparently very
heterogeneousat the scaleof an in situ test (say maybe 50 mm) may be quite
homogeneousat the scaleof a spreadfooting (say maybe 3000 mm).
8.
The creep settlementwas studied. It was found that the power law model proposed by
Briaud and Garland fit the data very well:
St -t n
-=
St, 0to
(5)
113
where st and St0are the settlementsof the footing after a time t and t, respectively. The
exponent n was found to vary from 0.01 to 0.05. For n = 0.03 the settlement at 50 years
would be 1.67 times larger than the settlementat 1 min. Therefore the creep settlement in
sandcannot be neglectedbut is not very large. The value of n for the footings increased
with the load level and decreasedwith unload-reload cycles and was, on the average,
equal to 2 times the n value obtained from the pressuremetertest:
n footing = 2n pressuremeter
9.
(6)
The soil movement at depth in the vertical direction was studied. For footing settlements
between 1 to 5 percent of B It was found that on the average36% of the top settlement
occurs between 0 and 0.5B below the footing, 42% between 0.5B and IB, 19% between
1B and 2B, and 3% below 2B. Therefore 2B seemsto be a reasonabledepth of influence
for such footings. The strain vs. depth profile obtained from the telltales shows a natural
decreasein strain with depth except close to the bottom of the footing where the strain
increasesdue to the lateral confinementbrought about by the roughnessof the footing.
10.
The soil movement at depth in the horizontal direction was studied. It was found that the
general shapeof the inclinometer curvesis a lateral bulging of the soil with a maximum at
a depth below the bottom of the footing averaging0.73B and a bottom at a depth below
the bottom of the footing averaging2.33B. The maximum horizontal movement at the
edge of the footing is of the order of 15% of the footing settlementand the horizontal
zone of influence extendsto about 1.8B beyond the edge on each side of the footing.
Approximate calculations indicate that the soil massunder the footing does not dilate but
instead compressesfor this medium densesand.
11.
A
new method for predicting the behavior of spreadfootings on sandwas developed. It is
drastically different from existing methods in that it gives a prediction of the complete load
settlementcurve. Becausethe deformation pattern under the footing resemblesthe
expansionof a cavity, the pressuremetertest was chosenas the basisfor the method. The
pressuremetercurve is simply transformed point by point to obtain the footing curve as
follows:
114
Pfooting = r Ppressuremeter
S
-- ARC
(8)
ii - 4.2R,
where Pfooting
(7)
is the pressuremeterpressure,IYis the
is the footing pressure,pnressmemeter
transfer function recommendedon the basisof the load test data and finite element
analysis,s is the footing settlementcorrespondingto pfooting,B is the footing width and
A&/R, is the relative increasein cavity radius on the pressuremetercurve at a pressure
equa1 to Ppressuremeter.
115
APPENDIX A: Soil Data
117
BORINB LOG
BGRmBIm SPT-1
LOCATIQI: SAND SITE
PRMZCT:PERFORllAWCEOF FOOTINGSON SARD
atmt
FmERu IIIOIYAY RDllIRIBTRATIOW
MY& b/5/93
#fURB:WBTAVlJS
Blows
Y!?
Weten
15Qlll~?~l5~
mwEcT10:140604
BOIL TEUWICUN: GXBBENS
J-Jar
/-No Ramvery
X-Penetration
Staple
#Shelby Tuba Srrpke
V-Water mccmtered
white drilling
\-DWurbsd
srple
from CuttfnBs
rOprrhole
water 1-l
B4F-Blows par foot, ASTM D 1586 Psnstration
Teat
of coq-essive
stramth
Pm.(tsf)-Field
estfmte
BNsmIPYI~
1.5 -
4&s/6
ND BAWLING
t/9/14
ND BAWLING
13/16/12
m, WRUNG
6/10/11
ND SAIPlING
B/10/13
t10 BAWLING
11/14/14
ND BMPLING
9/15/19
NOBANPLING
m/9
NOSANPLING
WV8
Yo BAWLING
wm34
'M BAWLING
19/29/47
NO SAMPLING
16/19/21
IK) BANPUNG
ww31
ND sAwpL!NG
of (CRAM
3,0-'
4.5 -
6.0
.7.5 -
9.0 -
'10.5-
' 12.G-
* 13s-
- lS.D-
BmNB TYPE: 121 m OXT
-ELM:
Bottom a 15.2 RI
Figure Al: SPT-I
118
m1nG Lmi
PRWBCT:PEBF~CEOF
FooIINGBoWSAW
CLIEBT: FWEBU 1-Y
MTE: 4/6/93
IwlIWIBTRATIW
in
WeI%
Blous
Per
15GWlPBm/l5&m
3.0 -
QDUDEIEV:
J-Jar
X-Penetration
Srrple
(Clheby T&a S-to
/-lo Recovery
encamtered tifLe drilling
Water
\-Dtrturbd
rrple
from aittitws
rQmhole
water Iml
BWBlom par foot, ABTM D 1% Penetratfon Te8t
Fuh<tsf)-FleLd
mime
of coproufve
streneth
aBaIPTIW
1.5 -
BWIW TYPE: 121 mmBft
PBwECTXD0146604
BOIL TECWICUW:GIBBENS
#1UEB:GUBTAWJS
1-h
#IX6
Yo: SPT-2
l.OCBTXaW:SAXD SITE
uw
Tan Silty
7/10113
Tan SfLty Fin, Sand
VW10
Tn Silty
Fin
619/o
Tan Silty
Fine Smd
4/s/B
Tan SlLty
Fina Sand
10/10/D
TanSand
7/9/a
TanSandn/Grmml
7/10/11
TM Smiy CLay
S/6/8
TanSandy Clay
6/6/13
In
11124139
Dark Gray Clay
11/16/24
Dark Gray Clay
14/17/22
Dark Gray Clay
18/25/32
Dark Gray Clay
OF mATIm
Fin. Smd
Snd
4.5 -
6.0 -
7.5 -
SjLty
Fine Swd
9.0 -
10s
12s
13.5-
'15.b
Bottom
Figure A2: SPT-2
119
a
15.2 ID
mR1na yo: SPT-3
UIUTIUR: SAND SITE
PROJRCT: PERFORWNCROF FOOTINGSON SAND
PRoJRmm14G6D4
myw&
mX. TEWRXCIAR:GXMENS
E
:
121 R BIT
J-Jar
/-No Recovery
ICShrlbytubsrrple
X-Penetraticn
Sllple
Water
enmntomd
&fle drilling
\-Dirtwbed
8-b
fma cuttfngl
rOprhole
water 1~1
R/F~Gloua per foot, ASTM D 1586 Pen&ration
Test
Fm.<tsf)-Field
estfnrte of c-iv,
rtremth
=I
1.5
zr
3
4
.
5/5/6
ran Silty
Fine Smd
4/8/10
ht
Silty
Firw Sand
6/11/14
rm
Silty
Fine sand
6/9/U
ran Silty
Fine Smd
6/8/10
m
Fine Sand
4/9/10
rM sud
6/12/14
m and
7/11/11
r8ft sandyclay w/Gravel
6/9/10
Tan Sandy Clay w/Gravel
3/5/5
102 mn of Tm Silty
11/20/24
26 mn of Clayey Greet
43/48/51
4
Dark Gray Clay
14/18/28
Dark Gray Clay
13/15/21
Dark Gray Clay
Silty
w/Grsvel
6.0
7.5 -j
Fina S8nd beccmea Tan Clay w/GraVOl
q9.0
12.D-
bacmms Dark Gray Clay
,13.5-
. 15.DBottom a 15.2 m
Figure A3: SPT-3
120
WRING LOG
bo11NG W: SPT-4
UIUTIDR: SARD SITE
PROJRCT: PERFORWICEOF FOOTINGSON SAND
‘rpth
in
ktem
Blows
15(lr/Y~15~
1.5
BGRIW YYFE: 121 nm SiT
-ELI%:
PRoJECTRD:1&6D4
WIL TRUWCUN: GfBBENS
DATE: h/16/95
DRxuRx: alsTNlJs
bhelby
T&e Sqle
~-Disturbed mle
fra
r--hole
umter lavel
b.<t8f)-Field
e&lute
J-Jar
X-Penetration
Srple
/-No Recovery
V-Water encomtered while drilLing
cuttfnG8
B/F-Blows per foot, ASTR D 1586 Penetration
Test
of corpreaslve
stramth
3/4/7
In Silty
Fine Sand
5/s/l
bn Silty
Fine Sfmd
5/8/10
ran Silty
Firm Sand
f/8/9
'm Silty
Fine Sand
5/8/8
fen Silty
Fine Sand
6/8/7
lan Sand
8/7I7
in Silty
Fine Sand
6/8/9
Ian Silty
Firm Sand
G/8/8
iravel
5/9/11
In
ll/23/27
76 ma of Ten Sandy Clay becanes Dark Gray Clay
21/31/39
Dark Gray Clay w/Gravel
14/21/32
Dark Gray Clay
17/23/3?
Dark Gray Clay
3.0
4.5
m
6.0
7.5
Sndy Clay
9.0
T
10.5
Tzc
'13s
* 15s
Bottom
Figure A4: SPT-4
121
a 15.2
m
mR1NG LOG
PRWEa:
PERFWUNCE OF FOOTINGSOw SAND
CLIENT: FWENAL III8fmY
DATE: 4/13/93
wnLEN: GusTAvus
lyh
&tern
BlOUS
Per
15oan/15oan/15Oata
GORINGNo: SPT-5
LOIWIW: SAND SITE
AwINmRAlIw
PRwEclm:14G604
SOIL l8CNNICIAN: GIGEENS
X-Penetration
Sample
J-Jer
bhelby
T&e 8-18
/-No Racwery
\-Disturbad
srple
from cuttings
Water
encountered nhfle drilling
ropan-hole
uater he1
8/F-Glow8 par foot, ASTM 0 1586 Penetration
Test
Pm.<tsf)-Field
estfnvte of capressfve
streiuth
88sc8IPTIoI
1.5 -
8oRIW YYP8: 121 111 BIT
QlQloEUV:
OF SmAnGl
4/5/S
Tan Silty
Fine Sand
S/7/8
Tan Silty
Ffne Sand
6/10/10
Tan Silty
Fine S~IKI
4/8/11
Tan Sflty
Fine Sand
4/7/9
TM Silty
Fine Sand
4/7/9
Tan Silty
Ffne Sud
8/12/U
TM Silty
Subd w/Gravel Pockets
6/7/11
Tan Sandy Cley w/Gravel
4/9/7
TanSand
4/12/13
102 11111
of Tan Sandy Clay W/Gravel becomes Gray Clayey Sand
12/33/31
51 any of Fine Sand w/Gravel becomes Dark Gray Clay
11/17/21
Dark Gray Clay
10/14/22
Dark Gray Clay
11/12/27
Dark Gray Clay
3.0
6.5 -
6.0 -
7.5 -
Bottom G 15.2 m
Figure A5: SPT-5
122
WRlNG LOG
GGRIN8 In: SPT-6
UIUTIOI: SAND SITE
PGWECT: PERFORWAWCR
OF FOOTINGSGN SANG
CLIEJIT: NIGIMY A#IINX8YRATIoW
MTE: 4/21/93
mw.uk GUSTAVUS
0lapth
in
wlater8
GlowJ
Per
15O1W15W15On1n
~yo:l4G6O4
SOIL YECINXCIAN: GIGGENS
X-Penetration
Svple
J-Jar
nshelby T&e Smple
/-No Recovery
\-Dfsturbed rlrple
fran cuttinge
Water
mco&mtered while drilling
v-Open-hole water level
B/F-BLowa per foot, ASTX D 1586 Penetration
Test
Pa.(M)-Field
estfmte of compressive strength
De3DIIPYXQI ff 8YRAnm
l.s
3.0
6/6/7
Tm Sflty
Fine Sand
6/8/11
Tm Sflty
Fine Sand
s/9/9
Tm Silty
Fine Sand
4/7/6
Tan Silty
Ffne Sad
4/7/l
Tm Smd
11/11/15
TmSand
s/9/14
Tm Sand u/Gravel
5/9/11
Gravel WSmd
7/13/U
Tm Sand w/Traces of Grrvel
3/4/4
No Recovery
9/20/29
76 A of Clayey Grwel became8Dark Gray Clay
12/20/31
.4
Dark Gray Clay
16/18/35
Dark Gray Clay
17/21/33
Dark Gray Clay
4.5 -
6.0
808116 TYFE: 121 ma BIT
WEUS:
9.0 -
15.GBottw
Figure A6: SPT-6
123
a 15.2 m
ANALYSIS
MECHANICAL
U. S.“Stondord
Sieve Openings
U. S. Standard
,.. .Inrhel,
..-..-In
CHART
Sieve Numbers
Hydrometer
100
=
2
0
so
10
50
20
70
WE
.g
z
50
sx
E
I
40B
-ti
50 .c
P
50
l-f
440
2
80,
z
e
70 2
B
i!so
20
110
10
So
0
,M
10
5
1
0.5
0.1
0.05
0.01
o..Mt
-.--.
on05
Groin Size in Millimeters
Coarse
GRAVEL
Fine
I
I
1 coarse
UNIFEO
BORING NO.:
DEPTH:
A
A
-
SPT-2
1.4m-1.8m
3.5m-4.0m
4.6m-5.0m
8.7m-9.lm
SAND
Medium
I
I
SOILlxA!smAlloN StslEY -
Fine
I
SILT OR CLAY
CORF’5OFEWNEERS.U.S.ARW
BORING NO.: HAND AUGERED HOLE
DEPTH: ___(c__
0.1 m
___t___
2.5 m
TEXASA&MRESEARCH
PROJECT
-8
CAMPUS
Figure A7: Grain SizeDistribution
MAY 26,
1993
100
Kd
2
II"
4
6
8
.'.'."""p"
10
Ed (bars)
12
14
16
18
200
400
600
\
6.
Id
Figure AS: DMT-1 TestResultsw/o Axial ThrustMeasurements
800
Ed (bars)
2
II"
4
6
8
's"'u'n"."'
10
12
14
16
0
18
”I
2.I
3,
4.
4,
6.
7.
I
x
5'
z
wa
n
6
I
1
7,
8.
8.
9.
9,
lo-
600
2
3"
z
EL
n
400
1
3,
.
200
101
1
Id
12345678
c
1,
2
3
4
8
Figure A!k DMT-2 TestResultsw/o Axial ThrustMeasurements
126
800
I
Kd
2
II."
4
6
8
a .'.I.
Ed (bars)
10
12 14 16
"I
.'.
18
'
;
‘. II
2’ II
3. II
4.
. II
Z”
E 6. II
4
n
, 4?0
, SVO
, 8?0
1
2
3
z
5.
E
8
cl
6
7.
'1
8.
1'
8.
g.
II
9
11
10 t
lo-
, 2?0
7.
Id
Figure AlO: DMT-3 TestResultsw/ Axial ThrustMeasurements
127
AXIAL THRUST (Kn)
0
Ii
5
10 15 20
I I I I I I I 25I I 30I I 35I I 40I I 45I ,
l-
2 -
3 -
4-
6 -
7 -
8-
9-
Figure All: Axial ThrustVersusDepthfor DMT-3
128
50
2i
5 8.0 1 O5
8f 6.0 1 o5
0.0 loo
2
0
4
6
8
Axial
Strain,
-
a3=3.45 lo5 Pa-
-
O~~1.38lo5 Pa
10
12
14
16
(%)
u3= 034 lo5 Pa
\
t
Figure AU: StressStrainCurvefor 0.6-m Sample
129
.-i
fj
-0.3
-0.4
.g -0.5
z -0.6
4 -0.7
’ -0.8
-0.9
Figure A13: VolumeChangeCurvefor 0.6-m Sample
130
III
I
I
11
l
l
11
: : : : : I1
: ; I,. . I,,
. , . I1I :( :, i, i, i, ‘i ‘: : 1; :1 iI
.:;i::.:;ijj,
:I i ; ! 1 : : i i :: . :
i . : f I !I.:
0
2
4
-
u,=3.4!5
105Pa
__c_
a,=138
105Pa
6
8
10
Axial Strain, (Oh)
-
12
a,=034
Figure A14: StressStrainCurvefor 3.0-mSample
131
14
16
105Pa
I
I
I I I
I I I I
I I I
I I I I
I
,Illll,lllllr‘ll!llillrrlllrl
0.1 I :::::
:.::::.::::::::;:
: : : : f ::::::::::,:::::::::::I’:::‘:
: ::::::::::i:iiiiii:i:i!ii
‘..‘...i..;..L..j..;..i..,~..j..i-..ij
“$g..i:i
f
0 .~t”*..i-‘~~~~~.~~~~~..~...~?
.,iiii;;i;;;i
;;iiijrijjiiii.iiiiijiiji
i izi-:;i.ii
. I
* . .
. .
..*..;..:..i..S..i..;..;..i..;..;.J..;..~...i..~..~...;..~..~...~..~..~..,~..~ .r..~...~..i.-i...~..~
-0.1
:jijIi:I:ljjiijijiliI::
:;ii;;ii;;
::
; x:::,:*:ii:.i:i::::
*:::i:
:
: ::::
i
:::
i :
ii: :‘i i
I : :
.~i...j..4..i’...~~“~..~~.~
i.-l”i..:..*..~.t”t’.!“*.‘t..t”t”
y..
i”$..t”.,“~..!“.*
3 -0.2
::;;;::ii
: : i
: : : : i i : i iii:
..~.~i...~..i..~..~..~..~..~..~~..~~..~
-+.
.~f-$.,f..~~..~..~..~“~...~..’
g -0.3
i ‘: . i :: :: i. II : :
.~~~~~~~~~~~~~~~
. Lf..+.i..y1.$.
* *..;...~..~..i...,..y...~..++..~.y.~...
6 -0.4
‘t”?
: ;
.g -0.5
E -0.6
g -0.7
s
'
-0.8
-0.9
i : , i;..*:’ :....f+...‘..+..+“~..+.+..+..<..+.j..+...:
: : :
--j..““”
::i : i:.::;:.:.t:
:i:::;;;
i:
‘:::2:
:I
-.i..J..k..~..5..~..~..~~~~.~~
:iljl:i::::::::iii::::i::ii:::i:Ii:
. . : . : I:ili:i~i::::ii:I::i::i~l:i::i
11’,,,,,,,1,‘,,,,,,,,,,1,,,,,,,,’,1
I
0
I
2
I
I
I
4
I
I
I
8
.i...;..f...j..~+..i--i.
i:;:::::
: : ! . : !
::I’::
-..~..?..~1-..I...~~...~~.~~~~~-
..f.f.+..f...?..~
6
I
I
I
I
10
12
Axial Strain. (%I
__IcI
a,=34
105PaT
-
a3=1.38
105Pa
I
I
14
I
I
I
16
18
a3= 0.34 1O5 Pa
Figure A15: VolumeChangeCurvefor 3.0-mSample
132
_
I
87-2
Y
6--
"O
c
5-
^
zi 4--
Normal
Stress,
(1 O2 kPa)
0.6 m Depth
87-';;‘
4
6--
"O
c
5--
f
4--
G-i
i
5
3-2-l--
Normal
Stress,
(1 O2 kPa)
3.0 m Depth
Figure A16: Mohr’s CirclesFrom TriaxialTest
133
Si
%
Sand (Depth:O.Om )
ensity =1514Kg/M3
Shear Strain
-E- MkPa S50kPa
-15OkPa-C2OOkPa~300kPa
1OOkPa
Figure A17: ResonantColumnTestResults@ 0.0 m
Clean Sand (Depth: 1.6 m )
Density = 1477 Kg/M3
*
200
180
I
l!k-05
I
I
I
.
-
I
I
I
llllll
I
I
I
I Illlll
-
.
’
I Illlll
l.OE-04
l.OE-03
Shear Strain
-2OkPa
-Wt5OkPa
-1OOkPe’
13OkPa-t3-2OOkPa~3OOkPe
Figure Al& ResonantColumnTestResults@ 1.6m
’
I
’ ’ ‘(~&mop
..-- -_
Clean Sand (Depth: 3.3 m)
Density = 1480 Kg/M3
200180
.-
80
I
-
--
60
L,,
40
- _--
-___
I I I11111
0 tL
20
1.oi-OS
u
1BE-04
1.OE-03
Shear Strain
I
_
-B-20kPa
+5OkPa
15OkPa-C 2OOkPa*
lOOkPa
300kPa I
Figure A19: ResonantColumn Test Results@ 3.3 m
-
.
. . .
‘1.ili-o2
Claye
Sand (De th: 6.0 m)
8 en&y: 2137 R g/m3
120- L-
100
s?
E
z
$al
5
80
1-
4ck-
2(I--
-1-1
-04
I
-01
’ ‘l-E:03
Shear Strain
e-m 150 kPa *
200 kPa -I&
300 kPa
Figure A20:
Resonant ColumnTestResults@ 6.0 m
BLOW COUNT, N
1
LEGEND
3
A SPT-1
I-J SPT-3
0 SPT-4
4
5
6
7
E
E
8
9
11
12
13
14
Figure A21: Graphof Blow CountsN VersusDepth for SPT 1,3 & 4
138
BLOW COUNT, N
LEGEND
A SPT-2
0 SPT-5
0 SPT-6
Figure A22: Graphof Blow CountsN VersusDepthfor SPT2,5 & 6
I39
PHI ANGLE (degrees)
0
III
4
8
II
12
11
16
11
20
1
'
24
1
'
28
1
32
"
36
'1'
0.5
1.0
LEGEND
A BHST-1
1.5
•I BHST-2
o BHST-3
2.0
2.5
3.0
3.5
4.0
4#
4.5
5.0
Figure AZ3: Graphof + VersusDepthFromBoreholeShearResults
140
40
0
0.0
FRICTION.
2.0.
0
PORE PRESSURE, TSF
10
20
30
0
TIP RESISTANCE. TSF
100
200
0
TSF
RATIn
. ,,_a
.”
2
t’
a
I
%>
10
50
i
50
lTsF=
95.8
kE’a
70
JOB NUMBER : 93-3006
ELEVATION
: 0.00
CPT NUMBER : 01
CONE NUMBER: FSCKEW593
DATE :
Figure A24: ConePenetrometerTestResultsfor CPT 1
141
01-27-1903
8
FRICTION. TSF
2.0
nn
0
PORE PRESSURE, TSF
10
2p
30
0
TIP RESISTANCE. TSF
100
200
0
0
2
RATIO (7.)
4
6
R
. .... .
. ...... ..
. 1.
....I.
......
.......
I
I
lo- c
60
jlTsF
70
= 95.8 kPa
ON I
I
I
80
JOB NUMBER : 93-3006
ELEVATION
: 0.00
CPT NUMBER : 02
CONE NUMBER: FSCKEW593
DATE :
Figure A25: ConePenetrometerTestResultsfor CPT 2
142
Ol-27-l?CZ
0 0.0
10 ’
0
PORE PRESSURE, TSF
10
2p
30
FRICTION, TSF
2,o
0
TIP RESISTANCE. TSF
100
200
0
I
I
(
I
I
RATIO (7.)
2
I(1
I
I
.
60 1
lTsJ?=
95.8
kPa
4
6
8
I
I
I
j
i,
I
1!
i 1
i
I
I
)
’
.
1
.#
I
70 -
80 -.
JOB NUMBER
I
ELEVATION
: 93-3006
: 0.00
CPT NUMBER : 05
CONE NUMBER: FSCKEW593
DATE :
Figure A26: ConePenetrometer
TestResultsfor CPT 5
143
OI-27-
1995
I
0
FRICTION,
2.0
(
10
5
\
0
PORE PRESSURE, TSF
10
20
0
TIP RESISTANCE. TSF
100
200
TSF
I
I
5
I
1-1
I
30
2
RATIO
4
I
I
20
30
50
60
l!rw=
95.8
kPa
'
70
8C
JOB NUMBER : 93-3006
ELEVATION
: 0.00
CPT NUMBER : 06
CONE NUMBER: FSCKEW586
DATE :
Figure A27: ConePenetrometer
TestResultsfor CPT 6
144
01-27-1993
PORE PRESSURE, TSF
10
2p
0
FRICTION.
30
TIP RESISTANCE, TSF
TSF
2
RATIO
4
5)
-
-
-1
I
I
-
-
-
-
50
60
l!rsF=
95.8
k.Pa
70
8C)A
JOB NUMBER
ELEVATION
wcflo GmsclCHaS.INC
: 93-3006
: 0.00
CPT NUMBER : C7
CONE NUMBER: F5CKEW588
DATE :
Figure A28: ConePenetrometer
TestResultsfor CPT 7
145
21-27-1995
initial
E, (kPa
Reload
Modulus,
~‘10’)
E, (kPa
Modulus,
Limit
x 10’)
Pressure,
PL (kPa)
200
400
600
800
1000
1200
4
2.
3.
i;
Q\
4.
E6
i%
n 7,
A
w
4
to 369548 kPa ot 10.8 m
to 173878 kPo at 10.8 m
9,
9.
9
10.
10,
10
ll-
ll-
11
Figure A29: Pressuremeter
TestResultsfor PMT- 1
to 4200 kPo at 10.8 m
Reload Modulus,
Er (kPa x 103)
Initial Modulus,
E, (kPa x4 103)
0
2
4
6
8
10
12
14
Limit Pressure,
PI W4
16
3,
4.
E
5’
I
ii
6.
6,
ii
7,
7
8.
8I
z-5
to 132929 kPa at 10.8 m
6
c
to 253725 kPa at 10.8 m
to
9,
9,
9
10.
10,
10
ll-
ll-
11
Figure A30: Pressuremeter
TestResultsfor PMT-2
4400
kP0
at 10.8 m
Initial
E, (kPa
2
Reload
Modulus,
4
Er (kPa
x4 10’ )
6
8
0
10
20
40
Modulus,
x
60
Limit
10’)
Pressure,
P, (kPa)
80
100
I
1
2
3
4
4.
z
5’
E”
E
6
F
6.
E
6
fii
n
7
El
n
7.
Ei
n
7
8
8.
8
9
9.
9
10
IO.
10
11
ll-
11
Figure A31: Pressuremeter
Test Resultsfor PMT-3
Initial
E,(kPa
Reload
tvlo~ulu;,
x 10
)
E, (kPa
Modulus,
Limit
x 103)
Pressure,
PL WW
0
3.
4.
5,
6.
7.
8,
9.
10.
1 lb
Figure A32: Pressuremeter
TestResultsfor PMT-4
200
400
600
800
1000
0.9
i
2
3
4
5
6
Normalized Time, (time / 1 min.)
7 6 91'0
PMTl.Deplh-0.6m.n,-0.017
+
PUfIDeph=S.lm.n,-0.030
0
pMTl.Dqh-1.3m.n,-0.013
Phall.mpch-21m.n,~O.011
A
8
PMTl.Depth-7.5rn.n,-0.016
pMTl.Depth-10.6m.nc-0.015
X
PWl.Degh-3.3m.n,-0.007
0
0
I
I
Figure A33: Determinationof the CreepExponentfor PMT-1
150
-.......--........
Figure A34: Determinationof the CreepExponH for Pm-2
151
Table Al: SteppedBlade Test Results
152
Table A2: Cross-HoleTest Results
North-South direction betweenholescht-2 andcht-1 (Figure3),
East-Westdirectionbetweenholescht-2 andcht-5 (Figure3),
153
Table A3: Summary of FieldResultsfor SPTEnergyMeasurements
Average
Rod Top
Force
0
*
l&4.0
D=3.54.0
R=5.5
/
Average
Ram Impact
Velocity
3-\
Average
Ram Kinetic
Energy
(kN-m)
0.28
TRltdeHd
E-xYW’I
AgiL
Avclage
Averago
System
Efficiency
Transferred
%
z
ON-m)
0.07
correoted
Tmnsfed
Enegy
[ASTM D4633-86)
(kN-m)
0.117
-51
SPT
Blow
COWt
(FF)
%
237
+!+
bYl50 mm
7/10/13
76.1
2.9
0.27
022
45
0.15
0.26
54
48
S/W10
70.8
3.0
0.28
023
48
0.15
0.26
54
49
6t9l9
71.6
3.0
0.28
026
54
0.16
0.22
46
47
4I8I8
66.8
2.8
0.26
0.18
38
0.19
0.22
46
50
10/10/9
71.6
3.0
0.28
023
49
0.20
0.23
49
48
7/9/S
76.5
3.0
0.27
023
48
0.23
0.26
53
50
7/10/l 1
71.2
2.9
0.26
026
54
0.23
0.24
51
47
51618
73.9
3.0
0.28
023
49
0.24
0.24
51
48
6/8/13
70.3
2.7
0.24
023
49
0.26
0.26
54
50
1l/24/39
77.0
2.8
024
0.24
51
0.28
0.28
60
48
llfl6f24
76.1
2.9
0.27
028
59
0.28
0.28
60
46
14117l22
75.7
2.8
0.24
024
51
0.27
0.27
57
50
M/25/32
E@vg) = 025
$avgl = 53
Table A4: PhysicalProperties
Sand
Sand
Property
I
0.6 m
I
3.0 m
MaximumDry Unit Weight(kN/m3)
15.70
16.10
MinimumDry Unit Weight(kN/m3)
13.35
13.66
I
Liauid Limit
N/P
I
N/p
I
PlasticLimit
SP-SM
SP
USCSClassification
NaturalVoid Ratio ?
I
155
0.78
I
0.75
I
Table AS: MoistureContentwith Depthfor SPT2 & 3
BORING
NO.
SPT-3
DEPTH
MOISTURE
IN METERS CONTENT
%
O-O.46
11.9
0.76-1.2
12.1
1.4-1.8
15.5
2.0-2.4
18.3
2.6-3.0
21.5
3.5-4.0
21.1
4.7-5.2
19.2
5.6-6.1
25.4
7.2-7.6
29.3
8.7-9.1
27.4
8.7-9.1
23.0
10.2-10.7
27.0
10.2-10.7
30.9
11.7-12.2
27.5
11.7-12.2
34.0
13.3-13.7
27.2
13.3-13.7
21.9
14.8-15.2
22.1
14.8-15.2
25.8
156
Table A6: Moisture Contentwith Depthfor SPT4 & 5
8.7-9.1
20.9
8.7-9.1
29.6
10.2-10.7
32.6
10.2-10.7
26.7
11.7-12.2
36.7
11.7-12.2
29.3
13.3-13.7
28.5
13.3-13.7
32.1
14.8-15.2
21.7
14.8-15.2
25.1
157
Table A7: MoistureContentwith Depthfor SPT6
8.7-9.1
-
10.2-10.7
28.6
11.7-12.2
29.0
13.3-13.7
30.7
14.8-15.2
23.4
158
APPENDIX B: Load-Settlement Curves
159
Load Settlement Curve - 1.O M Footing
Average Total History Curve
-110
-120
-130
-140
.- ...-. “.--r ; __.--.
j
..” --.. +-“+.-“.
--.,...,..i--;
;
;
--f---j----
;
-.j. --..”
...-._--.
+-.;
.. ... --.-
I
I
I
I
I
I
I
I
I
I
I
-170
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
Load
(MN)
Figure B1: Load SettlementCurve for 1.0-m Footing - Total History
160
Load Settlement Curve - 1.0 M Footing
Average 30 Minute Curve
-60
-70
El
i
-80
Q -90
%
m -100
-110
-120
-130
-140
-.-- - ... .i WI.. $” -.-- --+“..-.-+..“”
....-. c”’ . . .. + _........
-.-+.-+.“.
-I$()
m !
-__.4 -.-.““.. i .....--.-;-.-..-- &.“.” ..-- i.
__-.-b
-,70
!
0.0
1
1
j
I
I
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
Load (MN
Figure
B2: .Laad SettlementCurve for 1.O-mFooting - Avg. 30-min*&-ve
161
Load Settlement Curve - 1.5 M Footing
Average Total History Curve
-100
-110
-120
-130
-140
-150
-.--.-..e.......
..-.-
4
-160
0.0
. ..__.A
_-....
-*.-+”
..,. ““-+......“,-.~,.”
-.__.
:”
_.__..^
-...g”
-.....
-.--&.--~...-..-.~..
/
I
0.5
i
I
1.0
1.5
I
I
2.0
2.5
3.0
3.5
4.0
Load (MN)
Figure B3: Load SettlementCurve for 1.5-m Footing - Total History
162
4.5
5.0
Load Settlement Curve - 1.5 M Footing
Average 30 Minute Curve
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
bad (MN)
Figure B4: Load SettlementCurvefor l&n Footing- Avg. 3OMinuteCurve
163
5.0
Load Settlement Curve - 2.5 M Footing
Average Total History Curve
0
-10
-20
-30
-40
-50
-60
-100
-110
-120
-130
-140
-150
-II.-.--
“.+
---I
.
.
. ..A-
--.-..
“.+-.
__.._
“+---.....--c.~
---“p--...+
. ..-
.-ym--
1
-160
0
12
3
4
5
Load
6
7
8
(MN)
Figure B5: Load SettlementCurve for 2.5-mFooting - Total History
164
9
IO
Load Settlement Curve - 2.5 M Footing
Average 30 Minute Curve
0
I
-160
0
12
I
I
3
4
Load
I
I
I
5
6
7
I
6
9
(MN)
Figure B6: Load SettlementCurvefor 2.5-mFooting- Avg. 3OMinuteCurve
165
10
Load Settlement Cuwe - 3.0 M Footing
Average Total History Cuwe
NORTH
j
!
-150 - -.-.-.-;-.--.-...*~-~~~“~~-~~~~~~~
;
;
0I
-160 e
’
’
I
I
I
I
I
I
I
I
I
2
3
4
5
6
7
8
9
10
Ill2
Load
(MN)
Figure B7: Load SettlementCurve for 3.0-m(n) Footing - Total History
166
Load Settlement Curve - 3.0 M Footins
Average 30 Minute Curve
-
NORTH
0
-10
-20
-30
-40
-50
-60
-70
i
-80
3
8
-90
-100
-110
-120
-130
-140
-150
-160
0
1
2
3
4
5
Load
6
7
8
9
10
(MN)
Figure BS: Load Settlementfor3.0-m(n) Footing - Avg. 30 Minute Curve
167
11
12
Load Settlement Curve - 3.0 M Footing
Average Total History Curve
SOUTH
0
0
1
2
3
4
5
6
7
8
Figure B9: had Settlement Curve for 3.0-m(s) Footing - Total History
168
9
10
Load Settlement Curve - 3.0 M Footing
Average 30 Minute Curve
SOUTH
0
-140
-150
-160
0
12
3
4
5
6
7
8
9
~aww
Fkure BlO: Load Settlement Curve for 3.0-m(s)Footing- Avg. 3O-MinuteCurve
169
l0
APPENDIX C: Creep Curves
170
Individual Creep Exponent Curves
1.OM Footing
0.08
0.06
hm
e
3
3
1 0.04
.I6t
cl
8
4
0.02
0.00
0.0
I
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Log Time (minutes)
+
0.09MN +
0.18MN +
0.27h4N +
0.36 MN +
0.53MN +- 0.71MN
Figure Cl: Individual Creep Exponent Curves for 1.0-m Footing, 0.09 M-N - 0.71 m
171
I
Individual Creep Exponent Curves
1.Ofd Footing
0.08
-c
I
I
-.--
---
0.0
0.2
0.4
0.6
0.8
1.2
1.0
1.4
1.6
Log Time (minutes)
-e- 0.71MN -m- 0.89MN +
0.98MN -I-
1.07MN -h- 1.16MN -B- 1.25MN I
Figure c2: Individual Creep Exponent Curves for 1.0-n&&g,
172
0.71 MN - 1.25 MN
Individual Creep Exponent Curves
1.OM Footing
0.08
-
3
1
i
0.06
,+.e
y-
!
Figure
0.0
J
0.2
-t
1.34MN -I-
0.4
1.0
Log Time (minutes)
0.6
1.42MN -F
0.8
1.5lMN +
1.6OMN --t
C3: Individual Creep Exponent Curves for 1.O-nihoting,
173
1.2
1.4
1.6
1.69MN -N- 1.78MN
1.34 MN - 1.78 MN
Individual Creep Exponent Curve
1.OM Footing - 24 Hour Creep Test
0.12
0.10
i
1
I
;-......-.--.-~.-...--&--
.__.I. -.---.+
-.......-.-.-.-.-.
^ . .$ _.--.-.-.^,.._-
-..i
...I. ^ .,....-.-.-_,...
0.02
0.00
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Log Time (minutes)
Figure C4: Individual Creep Exponent Curve for 1.0-m Footing -24-Hour Creep Test
174
3.5
Individual Creep Exponent Curves
1.5 M Footing
0.08
0.06
0.02
0.00
0.0,
0.2
0.4
0.8
0.6
1.0
1.2
1.6
1.4
Log Time (minutes)
/ -e
0.27MN -#- 0.53MN +
0.8OMN -+
1.07IW-J-t-
1.34hdN +
1.34MN
Figure CJ: Individual Creep Exponent Curves for 1S-m Footing,0.27 MN - 1.34MN
175
I
Individual Creep Exponent Curves
1.5 M Footing
0.08
0.06
0.02
0.00
0.0,
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Log Time (minutes)
-O- 1.34MN +
1.74MN -v- 2.OOMN+
2.27MN -A- 2.54h~lN-a- 2.8Oh4N
I
Figure C6: Individual Creep Exponent Curves for 1.5-m Footing, 1.34 MN - 2.80 MN
176
Individual Creep Exponent Curves
1.5 M Footing
0.08
0.06
.
..“w-w
-.---._
“f.”
,
0.0,
“....---
-“.
,--...-.
.-“--.-.”
0.2
0.4
-I”-
-.-“-““.+““““.“.“.-
0.6
0.8
1.0
1.2
1.4
Log Time (minutes)
+ 3.07MN -a- 3.29MN
I
Figure C7: Individual Creep Exponent Curves for 1S-m ‘Footing, 3.07 MN - 3.29 MN
177
1.6
Individual Creep Exponent Curve
1.5 M Footing - 24 Hour Creep Test
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Log Time (minutes)
Figure CS: Individual Creep Exponent Curve for 1S-m Footing - 24 Hour Creep Test
178
Individual Creep Exponent Cuwes
2.5 M Footing
0.08
r
0.06
I
0.0
0.2
0.4
0.6
0.8
1.0
/
I
1.2
1.4
Log Time (minutes)
-e- 0.62MN +
1.25MN +
1.87h-lN +
2.49MN -A- 3.12MN
Figure c9: individual Creep Exponent Curves for 2.5-mFooting, 0.62 MN - 3.12 MN
179
1.6
Individual Creep Exponent Cuwes
2.5 M Footing
0.00 I
I
I
!
I
0.06
--.:
.“.--
A”“.“,
I
“,+.““---.+“..“.““-+-““~.~
-,“““--““““““““,
I
I
,
j
0.02
0.00 4
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Log Time (minutes)
+
4.36MN
+
4.98MN
+
5.61MN
+
6.23 MN
-A-
7.03MN
I
Figure ClO: Individual Creep Exponent Curves for 2.5-m-Footing, 4.36 MN - 7.03 MN
180
1.6
Individual Creep Exponent Cuwes
2.5 M Footing - 24 Hour Creep Tests
0.12
!
I
!
,
!
f
““.“.“““““““-.“.f
-..-
-“.“-““~-___
-“““+“-.-“~.-.
0.10
I
-
0.08
““.“.“.-““-
.. . --w.-“.“j.“.“.“.“.”
!
.-f.”
....- --_._
“““+“--.“.-“““..“.“+.“.““““..-““..j-.--..-
5
I
Q 0.06
3
.CI
II
WI
3
0.04
0.02
0.00
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Log Time (minutes)
[,112MN,I71MNI
Figure (Xl: Individual Creep Exponent Curves for 2.5-dFooting - 24 Hour CreepTests
181
Individual Creep Exponent Curves
3.0 k4Footing
NORTH
0.08
0.06
0:O
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Log Time (minutes)
-o- 0.89MN +
1.78MN +
2.67MN +
3.56MN -A- 4.45MN --a- 5.34MN
Figure Cl% Individual Creep Exponent Curves for3.0-m(n) Footing, 0.89 MN - 5.34 MN
182
Individual Creep Exponent Curves
3.0 k/l Footing
NORTH
0.08
I
/
0.06
0.0
,----f--F
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Log Time (minutes)
-a- 6.23MN +
Figure
C13:
7.12MN +
8.01MN +
8.9OMN -A- 9.79MN -B- 10.24MN
Individual Creep Exponent Curves for 3.0-m(n) Footing, 6.23 MN - 10.24 h4~
183
individual Creep Exponent Curve
3.0 M Footing - 24 Hobt Creep Test
NORTH
0.12
I
0.10
n 0.08
r(m
2
!
--
--.-+..-..-.-.--.-+..-..-.-.-
-___.__
-___.__
I
/
/
I
i -.--.-- ---._:
---._:
-.f.-....-...-.f.-....-...-
---
8
B 0.06
ert
s.W
n
en
3
0.04
-.--
:...-.““.-.
0.02
0.00
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Log Time (minutes)
+
4.45MN
I
Figure Cl4: Individual Creep Exponent Curve for 3.0-m@) Footing -24-HourCrew Test
184
3.5
Individual Creep Exponent. Curves
3.0 M Footing
SOUTH
0.08
I
!
!
I
2
i
+
0.08
i
.L
!
-..-....-.....A.-
_,--.,
d\ I
-..-.*
...^
....i.--.-.-..”
....~
0.0
0.2
0.4
0.6
0.6
Log Tie
-.-
0.89 MN +
1.78 MN +
1.0
1.2
1.4
(minutes)
2.67 MN +
3.56 MN +
4.45 MN -BF- 5.34 MN
Figure CM: ‘hdividuai Creep Exponent Curves for3.0-m’(s) Footing, 0.89 MN - 5.34 h4N
185
1.6
3.0 M Foo’ting
SOUTH
0.08
7
!
I
0.06
,.--,-
+
. ..-
.“.-.-
“.-.--.-
+I
I
h
g
z
4
f 0.04
.v!3
--._..._.,-___.
i
._...”
.
.
.
.
.
.._.-.
_,..
-,.
A..
*_._.-,_.-,
0.02
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Log Time(minutes)
+
6.23
MN +
7.12MN
+
8.01MN
+
8.9oh4N
Figure C16: Mividual Creep Exponent Curves for 3.0-m(s) Footing,6.23 MN - 8.90 MN
186
1.6
Individual Creep Exponent Curves
3.0 M Footing - 24 Hour Creep Tests
SOUTH
0.12
0.10
h 0.08
5
0.5
1.5
1.0
2.0
2.5
3.0
3.5
Log Time(minutes)
-1
Figure C17: b&dual
Creep Exponent Curves for3.0-m(s) Footing -24-Hour Creep Tests
187
Creep Exponent Curve
1.OM Footing
60
50
45
c
E
i-J//
25
y
i
I\
j
;
t -.7-’ ......._._.
&..” ....-j ._.I-....,_..
+. . ...+.--..--+&!Iy
___.
J
0
10 20 30 40 50 60 70 80 90 100110120130140
QO (‘W
Figure C18: Creep Exponent Curve for 1.0-m Footing - Qu = 1.48 MN
188
Creep Exponent Curve
1.5 M Footing
5
28
t__._.__
(.v.#
_......._._
1 ....I....k ._.-_..
1;
24
7-..-j.-..$.--j ;-....-y-...-p-.-...L
x
.y._.;._-...;-...J--.-.....
pfA :...-...
-._-.-.!
ji
I-.-._.....-2
J
20
16
....”..__
y -............
i-.. -.-.....
12
.(.
8
..-.-.-.-
.. i.. .... .... ..-._.
t .
-v....-.--.
j
4
.--....
I
0
0
i
i
.i ....._.____ .A..”
..^_ _ ; .__..... -:
:
I
I
j
/
I
j
“T
/
---.
I
r”
I
......
..-
r-
.^
“-
.... . ... ...-!-
..-.
... .
i
.” .-.-
,
...
+--.
;
..I._ --..F
I
.....
j
II....
I
:“” ---.-.
I
10 20 30 40 50 60 70 80 90 100110120130140
Q/QuWo)
Figure cl!k Creep Exponent Curve for 1.5-mFooting - Qu = 3.38 MN
189
Creep Exponent Curve
2.5 M Footing
,
36
2
28
:p;
f ...ylaad/
..-.-.-.“...~.....-.----..-.~.--..7’ &....---i
i ..yq!:;-.--.
-...j
..-.
“.&I
.
.
.._.
&“J
-...-.
j/
i
j
j
ihcjf- \ j‘\ i
/’
.-.-.-.-...
i.-..-.-..l...-I
-.-.i-..
-1:
Ii
24
20
0
10 20 30 40 50
60 70 80 90 100110120130140
Q/Qu(“A)
Figure C20: Creep Exponent Curve for 2.5mFooting - Qu = 8.50 MN
190
Creep Exponent Curve
3.0 M Footing
NORTH
60
56
_.-
.....$....e.~...“...
52
-.-+-.-A”
48
~~~~~.~.~~.
44
40
36
24
20
16
12
8
4
0
10 20 30 40 50 60 70 80 90 100110120130140
QfQu!%I
Figure C2l: Creep Exponent Curve for 3.0-m(n) Footing - Qu = 12.50 h4N
191
Creep Exponent Curve
3.0 M Footing
SOLJTH
--.1-f-+-
24
16
60
70
80
Q/Qu (‘W
Figure
c22: Creep Exponent Curve for 3.0-m(s) Footing - Qu = I 1.50 MN
192
APPENDIX D: Inclinometer Curves
193
1.78 MN Failure Test
1.0 M Footing - spt-6 (North-South)
- -
I
I ~.....-...A
.--- &---+...-
. ......-.
.-.y.-“-+
-9
-*-..---.--a
j
I
i
I
[-.-
. . . . -+-.
j
i
...--e.w..+--+1
\
/
;
i
1
I
-10
.--.
I-....“.-.+.---+--+---+“-
-..-~--.---.~--..-~-~-
I
1:
:
:
_..“.... -- .--_._.._. - -..--. j.-- ......-.....-
.-
-20
-16
-12
-8
--I
:
-4
_...” . ...-. -..I.
--_.. -..-i
-.....“-~
--...^“-___._
0
-.._--..-.
+.--.,
-.._
i-
. ....--~-.--~
-.--Y--.
:
-+-------
l
I
I
I
4
8
12
16
Deflection (mm)
I+
spt-6 (
Figure Dl: Inclinometer Test - 1.78~MNFailure Load - N-S Direction, 1.OM Footing
194
20
1.47 MN Creep & 3.29 MN Failure Tests
1.5 M Footing - spt-4 (North-South)
+.-._.
“.-.
..”
....
.+.-.
...
........
1,“.“-.“.
; ....:.”
..”
....“.
....
)-.-.
......
..”
.”
.”._._“.
...........
+._._._.
..............
1 i 1
.-,..
40
-8
-4
-6
-2
0
2
4
6
8
Deflection (mm)
f-
Creep Test +- Failure Test
Figure D2: Inclinometer Test - 1.47 &3.29-MNLAx~s - N-S Direction, 1.5 M Footing
195
IO
1.47 MN Creep & 3.29 MN Failure Tests
1.5 M Footing - spt-4 (East-West)
n
-8
_ ._._._._..........
.I ._._._.
._..........~__._._....,._....._.
/._._._......_..._.
/._.__............_,
-9
-10
-8
-6
-4
-2
0
2
Deflection (mm)
4
6
8
IO
+- Creep Test +- Failure Test
Figure D3: Inclinometer Test - 1.47 &3.29-MNLoads - E-W Direction, 1.5-mFooting
196
3.12 MN Creep Test
2.5 M Footing (North-South)
0
-1
-2
-3
-4
.....f-- _.......-....j-.--...
^--.-.-+.-5 ._._._...”
-6
8
a
-7
R
-8
-9
-10
-11
-12
_
. _.-
.
.
-. . ._ . . . . .
.
: : _._._,.............._
&!
i _._._......_.....
. . .._.,.........
y...
_._.....-....._._
“.y..
_......I,.......-.
“.
f...-
. .
.
+ ..,_._..........-._.
f -...............-.
+ ..”
i’”
. _
f
. .._...............
,_._..........,..,.
i
. .._._...............-.
_
_._._.,........,..,...
_.-._...............-
i _._._....,.........._
._...,_....._......_~~.~.~....
?-.”
,_.,.....,...._....
.,.....,...__,_.
+
. . . . . . . . . . . . . ..m.
_,,.....
..-
_
..- /_.___..._..,.....___+ ._._............ -.$.-
/
-13
._,..,_.............;
-14
-20
, _“_.
-16
. . . . . . . . . . . .._ j _._._............_._
-12
L.”
-8
._....,.............
T _ .
.
-4
_
..,.......”
.-._..
0
Deflection
i _.,..........-.-._._;
4
... .. . .
..._.”
._._
+...--.“.-.“.-.~
I
I
8
12
_._.-.-
16
(mm)
-u- spt-5 4- spt-2 +
spt-4
I
Figure D4: Inclinometer Test - 3.12 MN Creep Load - N-S Direction,
197
2.5-mF00th~
20
7.03 MN Failure Test
2.5 M Footing (North-South)
I
-“..,!-I”.-:.._.
+-*--
,-..., “.-.-.+.“.-.-~..““-.../
” ..._.......--. -.j-
. ....._.....-.y-.”
;
......--.-^.
... ..-. -,y,.” .I..._
-16
-12
-8
-4
0
4
-,-T--“‘--7”
_-,,..w
8
I
i._C(..
!
y...” -.--I
............-.- +..” .......-.+
-20
I
1
/--..- “.y-.--“-.“.“.-.
+-
12
-..-+-w
16
Deflection (mm)
+
spt-5 -+- spt-2 +
spt-4
Figure D5: Inclinometer Test -7.03~MN Failure Load - N-S Direction, 2.5mFooting
198
3.12 MN Creep Test
2.5 M Footing (East-West)
I I
-14
-20 -16
!
I
-12
-8
I
4
0
4
8
12
16
Deflection (mm)
Figure
1)6: hdnometer Test -3.lZh@J’Cmp
199
Load - E-W Direction, .2.5-mhothg
20
7.03 MN Failure Test
2.5 M Footing (East-West)
0
j
-1
j
/
/
-3 I
-4--
.-
f
1spt-5 : h = 0.9 ;n
)spt-2:h=2.9m
$+h=4.grn
j
/
/
?““‘““““-’
.I*.-.j-__i
-..--._
fl.
.
-----,
-5’
j
;
;
j
r
-6
8
9
8
-7
I.” ,..,. ~~~~~.~.~._~-~
;
-8
. . .. .. . -.A-“..
......I_.
+.. .I_...._. -.+---
._^_. A..““...-.-
j_.....--.
-j---.-..
-j- -...i -.._.-+-.-.-.-.+..-,..........
-y....d
...-.+.m-.“.~ :1
.........-.___..”
....-.-.y.....
-..-_ i.- ,..-. --$.-....._.e
-.I
-20
-16
-12
-8
-4
0
6
4
I
I
12
16
Deflection (mm)
+
spt-5 +- spt-2 +
spt4
I
Figure D7: Inclinometer Test -7.03~IviN Failure Load - E-W Direction, 2.%n Footing
200
20
4.45 MN Creep Test
3.0 M Footing - North (North-South)
O-
. ..I
I._.
I....
.
..-.j._..*_i-.__
I
f
-10
-8
-6
-4
-2
0
2
4
1
6
8
Deflection (mm)
i -t
spt-3 -t
spt-2 +
spt-1
Figure DS: Inclinometer Test -4.45~MNCreep Load - N-S Direction, 3.0-m(s) Footing
201
10
8.90 MN Failure Test
3.0 M Footing - North (North-South)
0
-1
-2
-3
4
-5
-6
-7
-8
-9
-10
-11
-20
-16
-12
-8
4
0
4
8
12
16
Deflection (mm)
+I
Figure D9: Inclinometer Test -8.90-m
Failure Load - N-S Direction, 3.0-m(n) Foot&
202
20
4.45 MN Creep Test
3.0 M Footing - North (East-West)
-1
-2
spt-2 : h = 2.9 m
spt-1 : h=5.5m
-3
_j _,.,_,_
I
4
-5
-9
-12
-13
10
-8
-6
4
-2
0
2
4
6
8
Deflection (mm)
-a- spt-3 -A- spt-2 -a- spt-1
I
Figure DlO: Inclinometer Test -4.45~MNCreep Load - E-W Direction, 3.0-m(n) Footing
203
10
8,90 MN Failure Test
3.0 M Footing - North (East-West)
1w
I
-14 - J
-20 -16
-12
c
I
I
e
I
I
I
I
-8
-4
0
4
8
12
16
Deflection
(mm)
Figure Dll: Inclinometer Test -8.90~MNFailure Load -E-W Direction, 3.0-m(n) Footing
204
20
4.45 MN Creep Test
3.0 M Footing - South (North-South)
0
-1
f
-2
-3
-4
---+pt-1
:h=O.Zm
/spt-2:h=2.7m
--1 spt-3 : h = 5.3 m
!
/
__________
-5
I
I
I
I
--
m-6
8
--
I
_I_-----__
I
I
I
-
-‘-
-
-
- i--I
I
/
-7
cI -8
_ -I_
,
I
I
-
-
- i--/
I
-
-’ I
I
I
-
-
- L--I
/
I
-
-’ l
-
-
-
g
-9
-10
--
i -
/
I
I
I
I
I
I
I
I
-
-
-
/
I
L I
I
I
-
-
_I_
I
I
I
-
-
-
L---I
I
I
-l----i----
L----‘----i----
L--I
-11
-12
-13
i----i----l----i---I
I
I
J----L----I----I----
--
I
-14
I
I
I
I
I
1
I
I
I
I
I
I
I
4
6
8
I
f
-8
-6
-4
-2
0
2
Deflection (mm)
j -m- spt-1
-A-
spt-2 + spt-3
I
Figure D12: Inclinometer Test -4.45~MNCreep Load - N-S Direction, 3.0-m(n) Footing
205
10
8.90 MN Failure Test
3.0 M Footing- South (North-South)
0
I
-1
I
I
I
1
-----------?-----~----I
I
#
I
/
I
I
I
I
I
I
I
I
I
I
I
1
---_-------------_--l
I
1
\
I
I
/
f
I
I
,
I
i-----I
1
L-----
-2
-3
.---
spt-1 :h=0.2m
ispt-2:h - --- -4
spt-3: h = 5.3 m
I
----------.l---------/
/---E-l
i
-4
-5
2
i
-6
-7
a
-8
1
---
I
I
--b:
%i
-H
-I-----------
I
.---
I
-1-----------
I
I
I
I
-9
-10
-11
-12
-13
-14
-20
-15
-10
-5
Deflection (mm)
1-w- spt-1 -A- spt-2 -.- spt-3
Figure D13: InclinometerTest- 8.90MN FailureLoad - N-S Direction,3.0 m(s)Footing
206
MN Creep Test
4.45
3.0 M Footing - South (East-West)
I
I
I
I
!-------I
I
i---I
I
,
-I----T--I
I
I
I
I
I-+---;--+----+---
/
:
-3 +---
I
I
/
spt-1:h=0.2m
: ---
I
t
&---;----;----;---
spt-2 :h=2.7m
spt-3 :h=5.3 m
f
-5 t-----:----t----l-----t---
-7
-8
-9
____
I
-10
f---v;
I
___I
I
I
I
I
I
I
I
I
;---;----;----~----j--I
I
42
j--v
+--++~-j----;--I
-11
i---t
t----~----t----~----t--I
I i-d I____
If ----1I-___
;-me
I /I III II
+ -___;
I
I
I
t----r----i----l----~---
i
j
I
I
-13 t----~---------i----:--/
I
I
/I
/
I
-14
I
4
-6
-10 -6
I
I
I
I
I
I
/
I
I
I
.-
____ ;----;----f--I
I
/
I
I
I
I
I
/
I
---l____
L---~-~~~~~~~
I
I
I
I
I
I
I
I
I
I
I
I
---_I---i---‘----L--I
I
I
I
I
I
,
I
/
I
I
I
---_I---L---‘----I--I
I
I
I
I
/
I
I
/
I
I
,
--- ‘----L----I____
I--/
I
I
I
I
I
I
I
I
I
/
I
--- J----L----I---I--l
I
I
I
I
I
/
I
/
I
I
I
--- -I- - _ _ I- - --I- ___ I--/
I
I
I
I
I
I
I
/
I
I
I
---i---I---I----L--I
I
I
I
I
I
I
I
I
I
I
/
I
I
0
2
-2
Deflection (mm)
--L----I----l--I
I
4
I
I
I
I
6
8
j/ -+ spt-1 +- spt-2 +- spt-3
Figure D14: Inclinometer Test -4.45~MN Creep Load - E-W Direction, 3.0-m(s) Footing
207
-I
10
8.90 MN Failure Test
3.0 M Footing - South (East-West)
0 T
-ll7z
-------I
I
-1
---
-2
i----1//
1I - - - 7I h-
I
I
-,----~-------I
I
I
I
l
I
I
I
-i-- t
/
/
;--I
---jspt-1 :h=O.Zm
/spt-2:h=2.7m
/I
--[--; spt-3: h = 5.3m
JI
I
I
----~------------_‘_-_
I
/
I
I
I
/
I
I
I
J----- -‘-1 - - - i/ - - _ _I_
_
_
_
1
I
I
I
I
I
I
I
I
I
--- -‘----L----‘---1--I
I
I
I
I
I
I
/
I --I---‘----J--I
I
I
1
I
I
I
I
I
I
--- _I/ - - - L1- - - -I-I - _ _ 1--I
I
/
I
I
I
I
L--_---I---_
-I----1--I
/
I
I
I
I
I
I
-3
4
-5
-6
8
g -7
cI -8
-9
-10
-11 I----l----i----l----~--I
-12
/
I
I
I
I
r---
--
-,
--
3i
;I--
-
-
--------------. 11
I
----------------__
-‘--- --_--_
I---I----------____‘---_
-------____‘---_
I
N--1--1
v
1
- _I-- --L-------- ---I
I
/
I
,
i!--:i
--J----L---‘----I----‘----I---:
--J----L--I
I
Yi I
L
-‘- - - - - _ - - _
-
f
?
_I:
-
-
I
i
I
----I---I
I
I
,
I
I
I
____I----1---I
-6
4
-
L-------------
I
I
I
I
I
I
I
I
I
/
I
I
I
I
1- - _II- - - - L--- -‘----I----
I
-13 .+----l----L
!
-l----T---
-------_--_-__.
/
--
----I---I
-8
----
---A----
/
+----;---+--;----f---
-10
--
-
---
I
I
I
J----L---J----I---I
I
-2
0
2
Deflection (mm)
/
I
I
i--I
/
L--I
/
/
L--/
/
I
I
I
-‘----L---I
I
I
-I----L---I
I
I
-I----I---I
I
I
I
I
I
I
I
I
I
I
I
I
/
I
I
I
I
I
I
I
4
6
8
IO
-+- spt-1 -A--spt-2 -.- spt-3
Figure D15: InclinometerTest- 8.90MN FailureLoad - E-W Direction,3.0 m(s)Footing
208
APPENDIX E: Telltale Results
209
S/S(top) versus Depth
1 .O M Footing
0.0
-0.5
-1.0
s -1.5
-2.0
-.-.,,-..--
I_--
. ...---.-
.i .......“”
-2.5
-3.0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
S/S(top)
-t 1% + 2% + 3% + 4% -5 5% +- 6%
Figure El: SettlementVersus Depth for 1.O-mFooting With Varying Percentagesof B
210
1.0
S/S(top) versus Depth
1.5 M Footing
0.0
-0.5
-1.0
“_.”
/i
/
--
. . ..-..
“.c.“.-.““....-----i”
.I.._._.
y”.‘“‘---i-”
.-..-
j
j
j
i
/
j
j
j
j
1;
I
/i
s -1.5
. . . . . . . “..-+.“-
... ..““7
-..... -.“~-...~~“.~~~.~.~“.“..“.“~.”
.,____
A...“.-.+
---+
-2.0
-2.5
-3.0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
S/S(top)
-e
1% +
2% -m- 3% -t 4% +
5% +
6%
I
Figure E2: SettlementVersus Depth for 1S-m Footing With Varying Percentagesof B
211
1.0
S/S(top) versus Depth
3.0 M Footing
-
SOUTH
s -1.5
-2.5
0.5
0.7
S/S(top)
+
1% + 2% +- 3% -+ 4% -a- 5% -i- 6%
Figure ES: ;SettlementVersus Depth for 3.0-m@) Footing With Varying Percentagesof B
212
S/S(top) versus Depth
3.0 M Footing
NORTH
0.0
i
!
-0.5
-1.0
---..-.
s -1.5
-2.0
-2.5
-3.0
0.0
0.2
0.4
0.6
0.8
S/S(top)
+
1%
+
2%
+
Figure E4: SettlementVersus Depth for3.@m(n)
213
3%
+
Footing
4%
With
+-
5%
Varying
-t
6%
Percentagesof B
1.0
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