IH September, 2022

SEPTEMBER, 2022
Volume: 50 § Number: 09 § Total Pages: 84
A View of Costal Highway on Dwarka - Probandar section of NH-51, in Gujarat
https://www.irc.nic.in
INDIAN HIGHWAYS
Volume : 50 § Number : 9 § SEPTEMBER 2022 § ISSN 0376-7256
Indian Roads Congress
Founded : On 10th December, 1934
CONTENTS
Ø
From the Editor’s Desk
4-5
Ø
Letter to Editor
6
Ø
Important Announcement
6
Ø
IRC Technical Committees Meeting Schedule for the Month of September 2022
Ø
Advertisements
81
2, 7-17, 45, 83 & 84
Technical Papers
Ø
Precast Reinforced Concrete three Radius Arch Pipe Culvert Bridges
By Aswathy S Nair & Dr. R. K. Ingle
18
Ø
A Rational Approach for the Analysis and Design of Jointed Plain Concrete Pavement with Non-Standard Dimensions
By Swati Roy Maitra & Atasi Das
28
Ø
Design of Reinforced Earth Retaining Wall in Submerged Condition
By Dr. S. K. Bagui, Dr. A.K. Sahu, Vishal Rathore, Saurabh Kumar & Satyabroto Mitra
36
Ø
Notifications
Ø
MoRT&H Circular
46-81
82
FEEDBACK
Suggestion/Observation on editorial and Technical Papers are welcome and may be sent to IRC Secretariat on
[email protected]/[email protected]
Publisher & Editor: Sanjay Kumar Nirmal, Secretary General, IRC
E-mail: [email protected]
Headquarter: IRC Bhawan, Kama Koti Marg, Sector-6, R.K. Puram, New Delhi-110 022.
Phone Nos.: +91-11-26171548 (Admn.), 23387140 & 23384543 (Membership, Tech. Papers and Indian Highways),
23387759 (Sale), 26185273 (Tech. Committees)
No part of this publication may be reproduced by any means without prior written permission from the Secretary General, IRC.
The responsibility of the contents and the opinions expressed in Indian Highways is exclusively of the author(s) concerned. IRC and the Editor
disclaim responsibility and liability for any statements or opinion, originality of contents and of any copyright violations by the authors. The
opinion expressed in the papers and contents published in the Indian Highways do not necessarily represent the views of the Editor or IRC.
Printed at: M/s B. M. Printing & Writing Papers Pvt. Ltd, (H-37, Sector-63, Noida), (UP)
` 20
GATI SHAKTI: THE NATIONAL MASTER PLAN
We are celebrating the Azadi Ka Amrit Mahotsav commemorating 75 years of independence
and the glorious history of Indian people, culture and achievements. This Mahotsav is dedicated
to the people of India who have not only been instrumental in bringing India thus far in its
evolutionary journey but also hold within them the power and potential to enable Prime
Minister's vision of activating India 2.0, fuelled by the spirit of Aatmanirbhar Bharat. Our
Hon'ble Prime Minister last year launched the Gati Shakti – National Master Plan for Multimodal Connectivity on 13th October, 2021 with aim to bring 16 Ministries including Ministry of
Road, Transport & Highways and Railways together for integrated planning and coordinated
implementation of infrastructure connectivity projects. Under this plan all 16 Ministries instead
of planning & designing domain areas infrastructure scheme like Bharatmala, Sagarmala,
inland waterways, dry/land ports, UDAN etc. and economic Zones like textile clusters,
pharmaceutical clusters, defence corridors, electronic parks, industrial corridors, fishing
clusters, agri zones separately in silos, they have to design and execute it with a common vision
to improve connectivity & make Indian businesses more competitive. The Gati Shakti Master
Plan is designed to enhance efficiency and have an integrated approach by use of latest satellite
imagery for visual understanding, coordination among all the stakeholders; synchronization in
implementation of projects; planning tools for route planning, land acquisition, permissions and
congestion reduction and dashboard based periodic monitoring for progress. The Gati Shakti is
ensuring that in coming years country does not waste money or time due to lack of coordination
in infrastructure projects. Everything, from roads to railways, from aviation to agriculture,
various ministries and departments would be linked.
We know that Resilient Transport infrastructure is critical for peoples' well-being, quality of
life, and economic prospects. Transportation is one of the most effective drivers for propelling
economic development. Various modes of transport are being used for movement of people and
goods. Our transport sector is large and diverse, with road transport contributing the major
share. In India, since beginning, in all “The Five Year Plans” Transport sector is accorded
importance. This is evident from budgetary allocations and stress given to have a systematically
planned Transportation System in the country.
The present focus of the government is to bring about efficiency in transportation of goods and
passengers. At the national level, efficient movement of cargo is gaining importance to reduce
the cost of transportation – currently the logistic cost in India is almost 14% of GDP as against
the global average of 8% of GDP. For Indian products to become competitive in the international
market, the logistic cost needs to be brought down significantly. This can be done by using the
most optimal mix of various modes of transport along with locating the Inland Container
Depots, Container Freight Stations and Air Freight Stations at optimal locations. These together
would reduce the logistic cost, thus bringing down the cost of products. Quality of infrastructure
is among the biggest hurdles facing the Indian government's ambitious programme, called
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INDIAN HIGHWAYS
SEPTEMBER 2022
“Make in India,” which aims to improve the nation's manufacturing capabilities and support
higher growth for generating employment.
Gati Shakti is different from the already announced national infrastructure pipeline and national
monetisation pipeline projects. Gati Shakti master plan is more about bringing the coordination
for the planning of all infrastructure connectivity projects that have been announced under the
national infrastructure pipeline. The Gati Shakti master plan will bring maximum planning and
coordination and minimise delays between the various ministries. The master plan would be
focusing more on ending inter-ministerial silos. Gati Shakti master pÏan will lead to optimum
utilisation of resources. It not only brings together the government process and its various
stakeholders but also helps to integrate different modes of transportation which is an extension
of holistic governance. The Rs. 100 lakh crore Gati Shakti plan envisages a centralised portal
comprising all existing and planned infrastructure initiatives of as many as 16 Central Ministries
and Departments for integrated planning and coordinated implementation of infra connectivity
projects. With the development of quality infrastructure, India can realize the dream of
becoming the business capital of the world.
The Gati Shakti programme marks a paradigm shift in decision making to break the silos of
departmentalism. In the proposed Plan, all the existing and proposed economic zones have been
mapped along with the multimodal connectivity infrastructure in a single platform. Individual
projects of different line Ministries would be examined and sanctioned in future within the
parameters of the overall Plan, leading to synchronisation of efforts. Gati Shakti will bring
synergy to create a world class, seamless multi-modal transport network in India. The National
Master Plan will employ modern technology and the latest IT tools for coordinated planning of
infrastructure. A GIS-based Enterprise Resource Planning system with 200+ layers for
evidence-based decision-making is one example. The use of satellite imagery for monitoring is
another. Digitisation will play a big role in ensuring timely clearances and flagging potential
issues, and in project monitoring as well. MoRT&H is implementing several initiatives to
improve the logistics efficiency and promote multi-modal connectivity across the nation.
Our country needs to develop quality, reliable, sustainable and resilient infrastructure, including
regional and trans-border infrastructure to support economic development and human wellbeing, with a focus on affordable and equitable access for all. The rapid growth in transport
infrastructure and services over the past decades has created new demands and challenges for
the transport sector. Fast economic growth contributed to high rates of urbanization, rising
traffic accident rates, new capacity constraints, and significant increase in asset preservation
requirements to meet the fast expansion of transport assets.
(Sanjay Kumar Nirmal)
Secretary General, IRC and
Director General (RD) & SS, MoRT&H
INDIAN HIGHWAYS
SEPTEMBER 2022
5
LETTER TO EDITOR/ANNOUNCEMENT
Respected Secretary General IRC,
I am glad to inform you that I have completed fifty (50) years as a Member of the Indian Roads Congress
(IRC). My Membership with IRC was very rewarding and provided me up to date technical information
related to highway engineering, highway construction and related technical research in India.
For last almost 50 years I am settled in the United States (US). In those years I have engineered and managed
various mega projects in US and other countries. I always kept in touch with IRC thru IRC magazines and
highway engineering activities in India.
I am proud that I am a life member of the IRC for last fifty years who provided me technical information
related to the highway engineering, I sincerely thanks IRC for that.
I am looking forward to attend one of the IRC conference/meeting in near future and share my over 50 years
of engineering and management experience with IRC members.
Thanks
Sincerely
Uday A Kumthekar,
IRC Life Member No.- 5418
Email: [email protected]
US Mobile No.(513)739 7120
Liberty Township, Ohio, USA
6
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TECHNICAL PAPER
PRECAST REINFORCED CONCRETE THREE RADIUS
ARCH PIPE CULVERT BRIDGES
A
SN
1
D .RKI
2
ABSTRACT
Three radius arch pipe composite bridges or culverts are provided under a roadway or railway as a cross drainage system
carry over the stream or as an underground tunnel or as an animal pass structure. Three radius arch pipe culverts, a complex
shaped pipe having three radii are using nowadays as a substitute to conventional type of culverts such as circular culvert and
box culverts. In this study, the various geometrical and structural features of the arch pipe are investigated using the
international codes Swedish standards, CHBDC (2014) and AASHTO LRFD (2017) and ASTM C 506 specification. The
strength of pipe is evaluated by means of three edge bearing test. The three radius arch pipe is proven to the best owing to the
advantages of its geometrical shape and hydraulic benefits compared to circular pipe and box culverts.
1.
performance of the arch pipe and its comparison is made
with circular pipes having equivalent size.
INTRODUCTION
Three radius arch pipe bridges owing to its advantages are
getting used as all kinds of bridge crossings more often as
an economic solution compared to the conventional steel
and concrete bridges. These are being used for small to
medium span cases up to 25 m and in locations where
construction time is less and continuity in traffic is
required. Generally, rectangular or circular in shape, bridge
culverts are constructed on rivers and canals.
2.
Precast reinforced concrete arch pipe is started using now a
days as substitute to the conventional type of culverts such
as circular pipe culverts, box culverts and arch culverts.
Reinforced arch pipe can be used for highway culverts,
railway culverts, short span highway bridges, storm drains,
utility tunnels etc. It is ideal for a variety of conditions such
as space constraints, limited fall and insufficient depth for
circular pipe. A three radius arch pipe is a pipe with three
radii and nearly flattened bottom. It consists of three radii,
top radius, bottom radius and corner radius. The bottom
radius is larger and the corner radius is the smallest. Fig. 1
shows the cross-section of a three radius arch pipe culvert
and Photo 1 shows precast reinforced concrete arch pipe.
Various shapes of culverts are being in use include circular
shape, elliptical shape, arch shape, pipe arch etc. Among
these, three radius arch pipe is now started gaining popularity
as a substitute to circular or box shaped culverts. But there are
no guidelines as per Indian codes of standards for the analysis
and design of arch pipe. The minimum depth of cover above
the conduit is determined using the guidelines provided in
Swedish, Canadian (CHBDC 2014) and American
(AASHTO LRFD 2017) codes for highway bridges.
In this Paper, some guidelines and features of precast
concrete three radius arch pipe are discussed. The
geometry of pipe is discussed with reference to ASTM C
506 (2013). The minimum depth of cover above the
conduit is determined, and the requirements and
construction guidelines of arch pipe are discussed. A three
edge bearing test is conducted to evaluate the mechanical
1 M.Tech Student, Email: [email protected]
2 Professor, Email: [email protected]
18
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}
THREE RADIUS ARCH PIPE
3.
GENERAL FEATURES
3.1
Geometry
The dimensions of arch pipe can be taken from ASTM C
506 (2013 a) which is the standard specification for
reinforced arch culvert and is given in Table 1. The culvert
geometry can be modeled using the following expression
given in ASTM C506 (2013).
Department of Applied Mechanics, Visvesvaraya National
Institute of Technology, Nagpur, Maharashtra
SEPTEMBER 2022
TECHNICAL PAPER
Fig.1 Three Radius Arch Pipe Culvert
Photo 1 Precast Concrete Arch Pipe
(https://line.17qq.com)
Table 1 Dimensions of Arch Pipe (ASTM C 506: 2013a.)
Approximate
Equivalent Round
Size, mm
Span,
mm
Rise,
mm
Water
Area, m2
R1,
mm
R2,
mm
R3,
mm
A,
mm
B,
mm
C,
mm
375
460
280
0.1
580
270
102
10
119
128
450
560
345
0.15
700
350
135
15
154
145
525
660
395
0.2
900
375
135
20
160
195
600
725
460
0.26
1035
370
115
90
151
248
750
920
570
0.41
1300
475
155
95
192
305
900
1110
675
0.59
1575
570
160
105
215
395
1050
1300
795
0.82
1855
665
190
130
248
460
1200
1485
915
1.06
2135
760
220
155
291
523
1350
1650
1015
1.33
2350
850
250
165
336
575
1500
1855
1145
1.64
2670
955
285
190
380
643
1800
2235
1370
2.38
3200
1145
320
225
436
798
2100
2590
1575
3.21
4130
1320
355
255
473
940
2250
2920
1830
4.13
4650
1500
490
330
611
970
2400
3100
1960
4.8
5535
1575
510
385
614
1040
2700
3505
2215
6.13
6835
1790
570
425
725
1183
3000
3910
2460
7.6
7655
1980
610
480
741
1345
3300
4285
2705
9.21
8355
2175
685
530
840
1458
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TECHNICAL PAPER
.........
.........
.........
.........
changing as the depth of cover changes. The live load will
get distributed through the soil fill and as the depth
increases, the intensity of live load on the pipe decreases.
CHBDC (2014), AASHTO LRFD (2017) and Swedish
Code provide formulae to determine the minimum soil
cover above the soil steel composite bridges. According to
CHBDC (2014), the minimum depth of cover (hc) above
the conduit should be maximum of the following.
.........
Where R1, R2 and R3 are the bottom radius, top radius and
corner radius, H is the rise of pipe and A, B and C are the
dimensions marked in Fig. 1.
3.2
.........
where, hc is the depth of cover soil.
Soil Material Requirements
Since the three-radius arch pipe is using as a soil steel
composite bridge, the properties of soil and the interaction
between the structure and the soil plays an important role on
the performance or arch pipe. The arch pipe should be placed
on prepared bedding and it should be provided with
structural backfill on either side of the pipe and on the top of
the pipe. Fig. 2 shows the soil filling requirements as per
Lars Pettersson et.al (2014).
i.
ii.
The soil below the arch pipe should be prepared soil
and it should be filled more than 0.3 m in depth below
the bottom most point and it should be placed with a
slope 1: n on either sides to a depth more than 0.2 times
the span of pipe.
On either sides of the pipe engineered soil should be
filled to a distance half of the span of pipe. The
properties of soil should be same as 1.
iii. The depth of soil backfill on the top of pipe should be
more than minimum depth of cover as discussed in
section 3.1. The density of material provided as cover
should be the average of densities of soil provided in
the region 1, 2 and 4. The soil can be gravelly sand or
sandy silt or silty clay.
Fig. 2 Soil Material Requirments
Table 2 Minimum Soil Cover Depth
Minimum depth of cover, m
SL
No.
Span
(D) m
Rise
(H) m
CHBDC
AASHTO
LFRD
Swedish
Design
1
1.485
0.915
1.054
0.300
≥0.5
2
1.65
1.015
1.057
0.300
≥0.5
3
1.855
1.145
1.050
0.300
≥0.5
4
2.235
1.37
1.065
0.300
≥0.5
5
2.59
1.575
1.082
0.324
≥0.5
6
2.92
1.83
1.018
0.365
≥0.5
7
3.1
1.96
1.001
0.388
≥0.5
iv.
There should be minimum 0.3 m base course material
above the soil filling on the top of pipe.
8
3.505
2.215
1.002
0.438
≥0.5
v.
All the soil in the region 1, 2, 3 and 4 should be
thoroughly compacted to the required standard
proctor density.
9
3.91
2.46
1.011
0.489
≥0.5
10
4.285
2.705
1.004
0.536
≥0.5
3.3
Minimum Depth of Cover
The depth of soil backfill above the conduit is termed as
cover depth and there is a minimum value of soil cover for
each pipe depending on the shape, span and rise of these
structures. The pressure due to vehicle load will be
20
INDIAN HIGHWAYS
SEPTEMBER 2022
Dh is the horizontal dimension or span (D)
Dv is the vertical dimension or rise of structure.
As per AASHTO LRFD (2017), the minimum soil cover
depth above the conduit should be,
hc = D/8 ≥ 0.30 m
(7)
According to Swedish design standards, the minimum soil
cover depth above the pipe should be more than 0.5 m. The
TECHNICAL PAPER
calculated values of minimum soil cover depth for arch
pipes of various spans and rise using the above formulae
are given in Table 2.
3.4
Hydraulic and Structural Benefits of Arch Pipe
Even though the shape of arch pipe is more complex
compared to circular pipe culvert and box culverts, the arch
pipe has greater advantages in terms of hydraulic and
structural aspects. Fig. 3 and 4 shows the comparison of
arch pipes, equivalent circular pipe and box culvert in
terms of water area.
In Fig. 3a and 3b shows the arch pipe and the approximate
equivalent circular pipe. It is observed that same water way
area which is obtained by using a circular pipe and box
culvert could be achieved with arch pipe having greater
span and less height. If circular pipe of same height as in the
case of arch pipe is provided, then only half of water way
area could be achieved. And hence multiple numbers of
circular pipes should have to be provided in such case
which is shown in Fig. 4. Similarly if circular pipe of same
span as in the case of arch pipe is provided, then the water
area obtained can also be obtained with arch pipe of greater
span and lesser depth.
It can be obtained that for the same water area, arch pipes
are more suitable to cover more length with less height
(a)
compared to circular pipe and box culvert. Table 3 shows
the dimensions of arch pipe and the equivalent circular pipe
and box culverts with the resultant water area. It is obtained
that arch pipe is suitable for limited headroom with
improved hydraulic capacity. In the case of sites having
depth constraints, the arch pipe can be provided instead of
providing multiple numbers of circular pipes and box
culverts having smaller section.
Fig. 5 shows the comparison of hydraulic radii of arch pipe
having a span of 2.92 m and rise 1.83 m and equivalent
circular pipes and boxes at various depths. Arch pipes and
circular pipes have the maximum R value when the depth of
flow (y) is equal to the 75% rise (H) of the pipe. It is obtained
that the equivalent circular pipes have slightly greater R
value compared to the arch pipes whereas in the case of box
culverts, the arch pipes have greater R value. From the Fig.
it is clear that arch pipes are having greater R value at low
flow conditions compared to box culverts and circular
pipes.
The hydraulic efficiency of pipes depends on the hydraulic
radius value and arch pipes are proven to have better
hydraulic efficiency at low flow conditions. For the sites
with limited fall conditions, arch pipes are more suitable
and economical instead of using multiple numbers of
circular pipes and box culverts.
(b)
(c)
Fig. 3 Water Area of Concrete Pipes (a) Arch Pipe of 2.235 m span (b) Circular Pipe Equivalent to
2.235 m Arch Pipe (c) Box Culvert Equivalent to 2.235 m Arch Pipe
Fig.4 Water Area of Circular and Arch Pipes
INDIAN HIGHWAYS
SEPTEMBER 2022
21
TECHNICAL PAPER
Table 3 Water Area of Arch Pipe and Equivalent Circular Pipe
Circular Pipe
Arch Pipe
Box Culvert
S. No.
Diameter (m)
Water area (m2)
Span (m)
Rise (m)
Water area (m2)
Size (m)
Water area (m2)
1
1.2
1.13
1.49
0.92
1.06
1
1.00
2
1.35
1.43
1.65
1.02
1.33
1.2
1.44
3
1.5
1.77
1.86
1.15
1.64
1.25
1.56
4
1.8
2.54
2.24
1.37
2.38
1.5
2.25
5
2.1
3.46
2.6
1.68
3.21
1.8
3.24
6
2.25
3.97
2.92
1.83
4.13
2
4.00
7
2.4
4.52
3.1
1.96
4.8
2.2
4.84
8
2.7
5.72
3.51
2.22
6.13
2.5
6.25
9
3
7.07
3.91
2.46
7.6
2.8
7.84
10
3.3
8.55
4.29
2.71
9.13
3
9.00
a) y = H
b) y = 0.75 H
c) y = 0.5 H
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INDIAN HIGHWAYS
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TECHNICAL PAPER
d) y = 0.25 H
Fig. 5 (a-d) Comparison of Hydraulic Radii
Fig.6 Reinforcement Details
3.5
Reinforcement
Fig.7 Schematic Representation of Three Edge
Bearing Test of Arch Pipe
The pipe arch can be designed as beam or column elements
depending upon the predominant force. It can be designed
as singly or doubly reinforced beam element as per
IRC:112-2020. Fig. 6 shows the layout of reinforcement to
be provided. Shear stirrups should be provided wherever
required.
4.
STRENGTH TEST OF ARCH PIPE
The mechanical performance of precast concrete arch pipe
can be examined by means of Three Edge Bearing Test
which is an external load crushing strength test consists of a
diametral compression test which helps to classify the
pipes under different classes. Fig. 7 shows the schematic
representation of three-edge bearing test of arch pipe. The
test procedures should be taken as per ASTM C 497(1998).
VNIT Nagpur has developed a model testing facility for
conducting three edge bearing test of three radius arch
pipes. Photos 2a and 2b shows photographs of arch pipe
specimens before conducting the test.
Photo 2a Arch Pipe Before Test
The three-edge bearing test has conducted on four arch pipe
specimens. Photo 3 shows the test setup for conducting
bearing test on arch pipes. From the test, it is seen that main
cracks are appeared at the top of bottom flat portion and
outer sides of the arch pipe. And hence, to enhance the
structural capacity of these pipes further, extra mesh of
reinforcement should be provided on these portions.
INDIAN HIGHWAYS
SEPTEMBER 2022
23
TECHNICAL PAPER
Photo 4a and 4b shows the photographs of deformed arch pipes.
Photo 2b Test Specimens of Three Edge Bearing Test
Photo 4a Cracks Observed at Bottom Flat Portion
Photo 3 Test Setup of Three Edge Bearing Test
Photo 4b Cracks Observed at Outer Sides
Fig. 8 shows the comparison of strength values of precast
concrete arch pipe of 2.235 m span and the equivalent
circular pipe of diameter 1.8 m. It was observed that the
strength of arch pipe is greater than that of equivalent
circular pipe. The three edge bearing strength value of arch
pipe is almost 2 times that of circular pipe.
controls should be noted on the construction drawings.
Some of the important things to be considered as per
CHBDC (2014) and IRC:122-2017 are listed below.
5.
CONSTRUCTION
Construction procedures are the most important factor
responsible for the structural integrity of a soil-steel bridge
and hence appropriate construction procedures and
5.1
Foundation
For the specific case of the foundation of a pipe-arch, the
following is recommended:
i.
When the foundation comprises dense to very dense
cohesionless material or stiff to hard cohesive
material, no treatment is required.
Fig.8 Comparison of Strength Values of Arch Pipe and Equivalent Circular Pipe
24
INDIAN HIGHWAYS
SEPTEMBER 2022
TECHNICAL PAPER
ii.
For soft to firm cohesive foundations, trench
reinforcement should be provided.
iii. For loose to compact cohesionless foundations, trench
reinforcement should be provided by in-situ
compaction.
5.2
done in such a way that, there are no permanent set results
in any portion of the wall. If struts are used to support the
conduit wall during backfilling, they should be removed
before they start restricting the free downward movement
of the crown. Photo 7 shows the assembling and erection of
arch pipe at site.
Bedding
The bedding on which the bottom of pipe rests, should be
composed of stone free granular material and it should be
pre-shaped in both the longitudinal and transverse
directions to accommodate the conduit invert. The top
layer of bedding, up to 200 mm thickness should be kept
un-compacted so that the ridges and valleys of the bottom
part of the pipe maintain uniform contact with the bedding
material.
5.3
Transportation
Before transporting, it should be ensured that the precast
units have gained adequate strength.
Photo 6 Lifting of Precast Arch Pipe
(https://www.flickr.com)
Photo 5 Unloading of Precast Arch Pipe
(https://www.flickr.com)
It should be loaded and unloaded carefully to and from the
delivery vehicle, and it should be adequately secured and
supported to prevent them from overturning, shifting or
being damaged during transportation. Photo 5 shows the
unloading of precast arch pipe units from the delivery
vehicle.
5.4
Handling
The precast products should be stored, transported and
handled in a manner to avoid damage. The handling
process includes demoulding of precast products, their
storage, loading and unloading, transportation to storage
spaces and site and erection. Care should be taken in order
to avoid stresses and damage in the precast units. Photo 6
shows the handling of precast arch pipe using mobile crane
lifting equipment.
5.5
Assembly and Erection
The assembling and erection of the conduit wall should be
Photo 7 Assembly and Erection of Arch Pipe
(https://www.flickr.com)
5.6
Engineered Backfill
The backfill should be placed in layers not more than 300 mm
thickness and compacted to the required density before
placing the next layer. On the either sides of the conduit, the
difference in levels of backfills the transverse direction should
not exceed 600 mm. The degree of compaction should not be
less than 85% of the Standard Proctor density. The backfill
material should be free of stones exceeding 80 mm in size
within a distance of 300 mm of the pipe and heavy
compaction equipment should be avoided within 1.0 m of the
pipe. In the proximity of the pipe light compaction equipment
should be used. Photo 8a and 8b shows the compaction of soil
backfill above and on the sides of arch pipe in site.
INDIAN HIGHWAYS
SEPTEMBER 2022
25
TECHNICAL PAPER
5.8
Joints
The joints and sealings should be done as per IS 15916:2010.
For precast reinforced concrete arch pipes, tongue and
groove joint can be provided. In tongue and groove joint, a
layer of cement paste or mortar is placed in the lower portion
of the groove and on the upper portion of the tongue of the
pipe. The tongue is then inserted into the groove of the
installed pipe until the sealant material is squeezed out onto
the interior or exterior surfaces. Fig. 9 shows an example of
section through the joint.
Photo 8a Compaction of Backfill around Arch Pipe
(https://www.flickr.com)
Photo 8b Compaction of Backfill around Arch Pipe
(https://www.flickr.com)
5.7
Headwalls and Appurtenances
The three radius arch pipe composite bridges are more
susceptible to damage by hydraulic effect and hence it
should be provided with headwalls and cut-off
appurtenances if it is designed for hydraulic purpose. When
a conduit wall at one of its ends is cut at a plane inclined to
the vertical, the continuity of the ring is no longer
maintained in the bevel, because of which the beveled ends
of the pipe should be designed as earth-retaining structures.
Photo 9 shows the arch pipe with headwalls provided at site.
Fig.9 Arch Pipe Joints (https://www.infolinks.com)
5.9
The inspection and supervision of construction of the soil
steel composite bridges should be provided as per
following.
I.
For three radius arch pipe composite bridges spanning
between 3 m and 6m, an engineer should inspect the
work at the completion of foundation, bedding,
assembly of pipe, and placement of backfill under the
haunches, up to the spring line, up to the crown, and up
to the level of minimum specified cover.
ii. For spans greater than 6 m but less than or equal to 8 m,
the inspection should be done as above and also daily
inspection under an engineer's supervision should be
made during the backfilling operations until a
minimum specified cover is attained.
iii. For structures with spans greater than 8 m continuous
inspection and supervision by an engineer should be
provided.
6.
i.
Photo 9 Arch Pipe with Head Wall Laid on Site
(https://line.17qq.com)
26
INDIAN HIGHWAYS
SEPTEMBER 2022
Site Supervision and Control
CONCLUSION
Precast reinforced concrete arch pipe with three radii
and flat bottom are suitable for short span bridges and
cross drainage structures.
TECHNICAL PAPER
ii.
The arch pipe can be used as a superior alternative to
multiple number of circular and arch pipes. The same
water area can be achieved with relatively less height
compared to circular and box pipes.
iii. Precast arch pipes are ideal for sites where space
constraints and limited headroom are present.
iv. Precast arch pipes have hydraulic efficient cross
section with improved hydraulic capacity and it is
ideal for low flow conditions with less scouring.
v. From the three edge bearing test conducted on arch
pipe, it is observed that main cracks are obtaining at
the top of bottom flat portion and at the outer sides of
the pipe. An extra mesh of reinforcement shall be
provided for further enhancement of structural
capacity.
The arch pipes performed better than the equivalent
circular pipe in bearing test and the arch pipe yields
greater strength.
vi.
The construction, handling, transportation, erection
and other related activities can be done as
conventional pipe culvert structures.
REFERENCES
1.
2.
3.
4.
5.
6.
Canadian Highway Bridge Design Code. (2014)
Guidelines for the Design, Evaluation and Structural
Rehabilitation Design of Fixed and Movable Highway
Bridges, CSA International, Toronto.
AASHTO LRFD. (2017). American Association of
State Highway and Transportation Officials. LRFD
Design Specifications for Highway Bridges,
Washington, DC.
ASTM C 506. (2020). Standard Specification for
Reinforced Concrete Arch Culvert, Storm Drain, and
Sewer Pipe. ASTM International, West Conshohocken,
PA.
Bakht, B. and Mufti, A. (2015). Bridges – Analysis
, D es ig n , S tr u ctu r al H ealth M o n ito r in g , an d
Rehabilitation, Springer, Switzerland.
Lars Pettersson, and Hakan Sundquist. (2007). Design
of Soil Steel Composite Bridges. Structural Design and
Bridges, ISSN 1103-4289.
Lars Pettersson, Amer Wadi, and Kevin Williams.
(2017). Structural Design of Flexible Culverts
Development Trends. Archives of Institute of Civil
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Engineering.
M., A., Perez, C., G., Butler, X., Fang. (2015). “Compute
Critical and Normal Depths of Arch and Elliptical
Pipes.” Journal of Irrigation and Drainage Engineering,
ASCE, ISSN 8, 0733-9437.
George Abdel-Sayed, and Sameh, R. Salib. (2002).
Minimum Depth of Soil Cover above Soil Steel Bridges.
Journal of Geotechnical and Geoenvironmental
Engineering, ASCE, 128, 672-681.
A., P., Morser and Steve Folkman. (2008). Buried Pipe
Design. Third edition, Mc graw hill Publishing, Utah,
Logan.
Damian Beben. (2009). Numerical Analysis of A SoilSteel Bridge Structure. Journal of Road and Bridge
Engineering. 4.13-21.
Damian Beben. (2020). Soil-Steel Bridges: Design,
Maintenance and Durability. Geotechnical, Geological
and Earthquake Engineering, 49, 1872- 4671.
Ece Erdogmus, Brian N. Skourup, and Maher Tadros.
(2010). Recommendations for Design of Reinforced
Concrete Pipe. Journal of Pipeline Systems Engineering
and Practice, 1(1), 25-32.
I., D., Moore. (2001). Buried Pipes and Culverts.
Geotechnical and Geoenvironmental Engineering
Handbook, 541-567.
IRC:6-2017. Standard Specifications and Code of
Practice for Concrete Road Bridges-Loads and Stresses,
Indian Road Congress, New Delhi.
IRC:112-2020. Code of Practice for Concrete Road
Bridges, Indian Road Congress, New Delhi.
IRC:122-2017. Guidelines for Construction of Precast
Concrete Segmental Box Culverts, Indian Road
Congress, New Delhi.
IRC:SP:13-2004. Guidelines for the Design of Small
Bridges and Culverts. Indian Road Congress, New
Delhi.
Indian Standard Code 783. (1985).Code of Practice for
Laying of Concrete Pipes, Bureau of Indian Standards,
New Delhi.
Indian Standard Code 458. (2003).Code of Practice for
P r e c a s t C o n c r e t e P i p e s ( Wi t h a n d Wi t h o u t
Reinforcement – Specification, Bureau of Indian
Standards, New Delhi.
INDIAN HIGHWAYS
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27
TECHNICAL PAPER
A RATIONAL APPROACH FOR THE ANALYSIS AND DESIGN
OF JOINTED PLAIN CONCRETE PAVEMENT WITH
NON-STANDARD DIMENSIONS
S
R
M
1
A
D
2
ABSTRACT
In Jointed Plain Concrete Pavement (JPCP), joints are provided in transverse and longitudinal directions by saw-cutting the slab up
to 1/3rd its depth to form rectangular slab panels. In India, the standard panel size for JPCP on highways is 3.5 m × 4.5 m. The 3.5 m
width of JPCP is provided considering the lane width. The lane markings are thus coinciding with the saw-cutting of longitudinal
joints. Some multi-lane highways, however, are constructed to have 8.5 m to 9.0 m wide carriageway with a single longitudinal joint
at the centre. The width of the panel thus becomes 4.25 m to 4.5 m. So, in this case, the lane markings are not coinciding with the
longitudinal joint. This results in a larger proportion of traffic being close to the central longitudinal joint as compared to the
situation where the lane markings match with the longitudinal joints for pavements with panel size of 3.5 m × 4.5 m. In India, the
design of rigid pavement is generally done considering a finite element based approach as given in IRC:58-2015, where stress charts
and equations are provided to determine the critical stresses. However, these stress charts and equation have been developed only
for a panel size of 3.5 m × 4.5 m, thus cannot be used for other panel sizes. Therefore, a separate finite element analysis is required to
estimate the critical stresses for pavements with non-standard dimensions. In the present work, a rational approach is considered
for the design of JPCP of non-standard dimensions. A three-dimensional finite element model has been developed for the analysis of
JPCP with panel dimension of 4.5 m × 4.5 m and the critical stresses are estimated. A traffic survey was carried out on a similar road
to assess the proportion of traffic near the central longitudinal joint, based on which the design traffic is estimated. Considering this
design traffic and the critical stresses obtained from the finite element analysis, the design of pavement has been done. The approach
has been utilized for design of rigid pavement on a road project in India.
1.
INTRODUCTION
In recent years, the development of road infrastructure has
become a priority area by the Government of India. Various
road development projects have been taken up for upgrading
and widening the existing roads. In many of these projects,
concrete pavements are constructed on several stretches of the
highways. These pavements provide good riding quality and
because of their high strength and rigidity, they can withstand
heavy traffic with less deterioration, thus have less
maintenance and longer service life. In India, Jointed Plain
Concrete Pavement (JPCP) is the most commonly
constructed concrete pavement for highways. In JPCP, joints
are provided in transverse and longitudinal directions by sawcutting the slab to form rectangular panels. The standard panel
size followed in India is 3.5 m × 4.5 m, with longer side along
the direction of traffic (separated by transverse joints). The
panel width is kept as 3.5 m considering typical lane width.
For a standard two-lane highway with carriageway of 8.5 m to
9.0 m, generally two longitudinal joints are saw-cut at
distances of 1.5 m and 5.0 m from the left edge so that a 1.5 m
wide paved shoulder and two adjacent panels each having a
width of 3.5 m are formed. No joint is provided at the right
end of the carriageway as there exists the median. The lane
markings are provided to separate the 1.5 m wide shoulder
and the two adjacent lanes of width 3.5 m each. The lane
markings are thus coinciding with the longitudinal joints at
the side and also at the centre. Some multi-lane highways are,
however, constructed with 8.5 m to 9.0 m wide carriageway
having a single longitudinal joint at the centre. The width of
the panel thus becomes 4.25 m to 4.5 m, though the transverse
joint spacing generally remains the same as 4.5 m along the
traffic direction (panel dimension thus formed is either 4.25 m
× 4.5 m or 4.5 m × 4.5 m). Lane markings are provided in such
1 Assistant Professor, Email: [email protected], Ranbir & Chitra Gupta School of Infrastructure Design and Management,
Indian Institute of Technology Kharagpur
2 Assistant Vice President– Design, Email: [email protected], GR Infraprojects Limited
28
INDIAN HIGHWAYS
SEPTEMBER 2022
TECHNICAL PAPER
a way that the standard lane width of 3.5 m is maintained.
Since there is no other longitudinal joint except the central
one, the shoulder of width 1.5 m is also separated by lane
markings only. Thus, in this case, the lane marking at the
centre is not coinciding with the central longitudinal joint.
This practically causes the central longitudinal joint to
become the wheel path of vehicles which eventually results in
a larger proportion of traffic being close to the joint, as
compared to the situation when the lane markings match with
the longitudinal joints for panel size of 3.5 m × 4.5 m. For the
design of pavement of such non-standard dimensions, it is
therefore, important to take into consideration this larger
proportion of traffic while estimating the design traffic.
Though IRC:58–2015 has recognized this issue, however, no
recommendation has been provided in the guideline for the
consideration of design traffic for such type of non-standard
pavements.
Another important consideration is the estimation of
critical stresses for the design of pavement. In the design
guideline IRC:58–2015, a number of stress charts and
equations have been developed to determine the critical
stresses on the pavement based on a Finite Element (FE)
analysis solely for the standard panel size of 3.5 m × 4.5 m.
Therefore, these charts and equations are not applicable for
determining the stresses for pavements other than the
standard dimensions. A separate FE analysis is therefore,
necessary for estimating the critical stresses for the design
of such non-standard pavements.
Realizing these issues, a rational approach has been
suggested in the present work for the design of JPCP of
non-standard panel sizes. The present approach has been
applied on a real life road project to design a rigid pavement
of dimension 4.5 m × 4.5 m. This Paper describes the
application of this rational approach for the design of a
JPCP of dimension 4.5 m × 4.5 m for a project road stretch
on National Highway (NH) 151 in the State of Gujarat. To
assess the proportion of traffic on the project road, a
specific traffic survey was carried out on a similar concrete
road. The results of the traffic survey provided the
necessary inputs in estimating the design traffic for the
project road in a judicious manner. For determining the
critical stresses, a three-dimensional FE model has been
developed for a two-panel concrete pavement with panel
size 4.5 m × 4.5 m separated by a longitudinal joint at its
centre. Analysis has been carried out for wheel loads
placed at different locations combined with positive and
negative temperature gradients, and the flexural stresses
are obtained for critical conditions. Considering the design
traffic and the maximum stresses obtained from the FE
analysis for different classes of single, tandem and tridem
axles, the design of pavement is done based on critical
stress criteria and cumulative Fatigue Damage Criteria
(PCA, 1984). The details of the design approach along with
the modelling technique are discussed in the following
sections. The work is particularly relevant and highly
significant to the highway professionals as it provides a
rational basis for the design of JPCP of non-standard
dimensions.
2.
CONCRETE PAVEMENT IN INDIA
In India, a typical jointed plain concrete pavement consists
of plain cement concrete slab, Dry Lean Concrete (DLC)
base, granular subbase over a well-compacted subgrade. A
150-micron polythene sheet is also provided in between the
concrete slab and the DLC layer to make the interface
smooth to account for thermal expansion and contraction
due to seasonal temperature variation. In JPCP, joints are
provided in transverse and longitudinal directions by sawcutting the slab up to 1/3rd its depth within 8-24 hours of
casting. Rectangular panels are thus formed by these joints.
The standard panel size generally followed on Indian
highways is 3.5 m × 4.5 m. However, other panel sizes are
also used depending on the traffic, soil conditions and
available road width. Adjacent slab panels, along the width
of the pavement, are separated by longitudinal joints. A
1.5-2.0 m wide shoulder is generally provided with the
same Pavement Quality Concrete (PQC) on both sides of
the pavement which may also be separated by longitudinal
joints. Deformed tie bars are provided along the
longitudinal joints to hold the slab panels in their positions.
Perpendicular to the traffic direction, the panels are
separated by transverse joints, where a series of mild steel
dowel bars are provided for transferring the applied wheel
load from one panel to the adjacent panel and also to
maintain the continuity of the pavement. For the design of
JPCP, the primary considerations are traffic characteristics
which include number of commercial vehicles per day,
traffic growth rate, axle load spectrum, tyre pressure, wheel
base characteristics, lateral placement of axles and
directional distribution; soil characteristics and
temperature variations in the region. The effects of nonlinear temperature gradient during day time and linear
temperature gradient during night time are considered in
design along with zero-stress temperature gradient
(IRC:58–2015). The standard grade of PQC is M40, with
characteristics compressive strength of 40 MPa at 28 days.
Soil strength is expressed in terms of modulus of subgrade
reaction. The design is generally done for a period of 30
years. The Indian Roads Congress guidelines followed are
IRC:58-2015 for design and IRC:15-2017 for construction
of rigid pavement in the country.
3.
DETAILS OF THE PROJECT ROAD
A road development project was taken up for up gradation of
an existing pavement for four-laning with paved shoulder on
a stretch of NH-151 in the State of Gujarat. The existing
carriageway had flexible pavement with two lanes and paved
shoulder. The upgradation was considered for the entire
stretch with four-lane rigid pavement divided carriageway
INDIAN HIGHWAYS
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29
TECHNICAL PAPER
having a total width of 18 m. This included 1.5 m wide paved
shoulder on both sides and 500 mm shyness marking on
either side of the median. Field surveys and material
investigations were carried out on the project stretch which
provided the required inputs for the design of pavement.
Material investigations included evaluation of existing
subgrade soil, evaluation of alignment soil in widening areas
and evaluation of borrow earth materials. Based on the soil
test results, the effective CBR for subgrade was adopted as
10%. Pavement condition survey was carried out and the
pavement distresses in terms of cracking, potholes, ravelling,
rutting etc. were measured along with embankment and
drainage conditions. Based on the survey, the condition of
the existing pavement was found as fairly good. The existing
pavement composition survey was carried out by digging
trial pits on the carriageway and at junctions of pavement
and shoulder. The existing pavement had bituminous
surfacing of thickness ranging from 60 to 280 mm and
granular layers of thickness ranging from 220 to 585 mm.
Traffic surveys were carried out which included origindestination survey, axle load survey and classified volume
count survey. The axle load survey on the project road
indicated that there was a wide range of traffic including bus,
light and few heavy commercial vehicles, with single,
tandem and tridem axles. The highest load groups with
single, tandem and tridem axles were 155-165 kN, 320-340
kN and 440-470 kN, respectively and the lowest load groups
with single, tandem and tride max les were below 85 kN,
below 180 kN and below 230 kN, respectively. The
percentage of vehicles in the highest load groups were 0.2%,
0.8% and 1.2% for single, tandem and tridem axles
respectively; whereas 90.2% of the single axle vehicles were
in the load group below 85 kN, 74.8% of the tandem axles
were in the load group below 180 kN and 45.8% of the
tridem axles were in the load group below 230 kN in the
project road. The average number of axles per commercial
vehicle was calculated as 2.89. Traffic growth rate on the
project road was estimated using transport demand elasticity
method. For bus and truck, the growth rate was estimated as
5% while for LCV it was 9% for the entire design period of
30 years. The number of commercial vehicles per day on the
project road was estimated as 2082 from the classified traffic
volume count survey and the total two-way commercial
vehicles during the design period was estimated as
59824270.
4.
APPROACH OF WORK
In the present work, a rational approach has been followed
for the design of JPCP having non-standard dimensions of
4.5 m × 4.5 m for the above-mentioned project road. In
IRC:58-2015, stress charts and equations are provided
which are based on a finite element analysis for standard
panel sizes of 3.5 m × 4.5 m only. Therefore, the same
equations and stress charts are not applicable for other
panel sizes. Also, since the central longitudinal joint
30
INDIAN HIGHWAYS
SEPTEMBER 2022
actually falls within the carriageway, the lane markings are
not matching with the longitudinal joints for larger panel
width. As a result, a greater proportion of traffic will move
along the central longitudinal joint leading to a higher
design traffic as compared to that for JPCP with 3.5 m wide
panel. Therefore, for the design of such non-standard
pavements, two major steps have been considered in the
present work, which are (a) development of a finite element
model for JPCP of panel size of 4.5 m × 4.5 m for the
estimation of critical stresses on the pavement and (b)
determination of the proportion of traffic on the road by
conducting a specific traffic survey for estimation of design
traffic. The details of the design approach with finite
element modelling and the determination of design traffic
are discussed in the following sub-sections.
4.1
Development of Finite Element Model
A three-dimensional (3D) finite element model has been
developed in the present work for the JPCP of the project
road using the commercial structural analysis software
ANSYS (ANSYS, 2017). In developing the FE model, two
adjacent slab panels of the pavement have been considered
with a single longitudinal joint in between. Each panel has
the dimension of 4.5 m × 4.5 m with a thickness of 280 mm.
Foundation is considered to be composed of 150 mm thick
DLC base, 150 mm thick granular subbase and compacted
subgrade as used in the project stretch. For the subgrade
CBR of 10% as obtained from the soil investigation results,
the corresponding modulus of subgrade reaction is taken as
55 MPa/m (Refer Table 2 of IRC:58-2015). Considering a
150 mm thick DLC layer below the PQC, the effective
modulus of subgrade reaction (k) for the entire foundation
is considered as 300 MPa/m for the analysis (Refer Table 4
of IRC:58-2015). The material properties for M40 grade of
concrete have been taken as given in the design report,
which are: elastic modulus (E) = 30,000 MPa, Poisson's
ratio (μ) = 0.15, compressive strength (fck) at 28 days = 40
MPa, flexural strength (fcr) = 4.5 MPa, density (γ) = 24
kN/m3 and coefficient of thermal expansion (α)= 10×10-6/º
Centigrade.
In the FE model, concrete slab has been modelled using 8noded solid brick elements (Maitra et. al., 2009a). The brick
element has 3 degrees of freedom per node, which are
transactional displacements along the x, y and z directions.
PQC has been modelled as linear elastic and isotropic
material with the above-mentioned material properties. The
combined foundation is modelled as Winkler foundation
(Westergaard, 1926), with the effective modulus of subgrade
reaction (k) as 300 MPa/m. Winkler foundation assumes that
the soil is composed of a bed of linear springs and the contact
pressure at any point is proportional to the deflection of the
soil at that point and is independent of the deflections at other
locations. Two-noded linear spring elements are used to
TECHNICAL PAPER
represent the Winkler foundation in the present work.The
spring elements are connected to the bottom node of the brick
elements of concrete slab at one end while the other end is
kept fixed (Maitra et al., 2009). The spring constant is
estimated using the modulus of subgrade reaction with the
corresponding effective bearing area of the spring. Mesh
convergence study has been carried out based on which an
element size of 80 mm ×80 mm ×80 mm has been finalized
for the concrete slab. Dowel bars are not modelled, however,
continuity due to the presence of dowel bars have been
simulated by providing necessary boundary conditions along
the transverse joints, similar to that found in literature
(Chintankumar, 2010; Surya Teja et al., 2017). Likewise, tie
bars are not modelled, but the connection between the
adjacent slab panels are simulated by aggregate interlocking
along the central longitudinal joint, as done in other research
works in literature (Maitra et al., 2015). The aggregate
interlocking is represented by a set of linear springs below the
saw-cut depth of the longitudinal joint (Maitra et al., 2010).
Fig. 1 shows the FE representation of the jointed concrete
pavement supported on Winkler foundation. The FE
modelling approach with aggregate interlocking joint was
validated with experimental works reported in literature and
also with the results of FWD testing (carried out by the first
author) on an in-service concrete pavement, which were
already published in earlier research works by the first author
(Maitra et al., 2010; Maitra et al., 2015) and, therefore, is not
repeated here.
at critical locations on the pavement are obtained for different
wheel load positions along with positive or negative temperature
differentials to check for BUC and TDC conditions.
The critical locations for bottom-up cracking condition are
shown in Fig.2. Using the FE model, critical stresses at
each of these locations have been found out when the wheel
load is placed at that location along with maximum positive
temperature gradient of 19.2ºC. For bottom-up cracking,
the maximum stress occurs when one wheel of the dual
wheel assembly is placed touching the outer edge of the
pavement midway between two transverse joints (load
position L1) along with positive temperature gradient.
When the wheel load is touching the inner edge/central
longitudinal joint of the pavement (load position L2), or
when one wheel is on the central longitudinal joint (load
position L3), the stresses are marginally less as compared
to that at L1, as obtained from the FE analysis. The
reduction in stress near the joint is due to the continuity of
pavement along the central longitudinal joint with some
amount of load transfer due to aggregate interlocking. This
is true for both single axle and tandem axle loads on the
pavement.
Fig. 2 Axle Load Positions for BUC
Fig. 1 FE Model of Concrete Pavement with
Panel Size 4.5 m × 4.5 m
4.2
Results of Finite Element Analysis
The modelled pavement has been analysed for axle loads at
different positions on the pavement along with temperature
gradient through the slab depth.The maximum positive
temperature differential in the State of Gujarat is 15.8ºC while in
the coastal areas it is 19.2ºC (Refer Table 1 of IRC:58 - 2015).
Since the project stretch is near the coastal areas of Gujarat, the
maximum positive temperature gradient has been taken as
19.2ºC, whereas the maximum negative temperature gradient
has been taken as 14.6ºC. From the FE analysis, flexural stresses
The critical locations for top-down cracking are shown in
Fig.3. In a similar way, using the FE model, critical stresses
at each of these locations are obtained when the wheel load
is placed at that location along with negative temperature
gradient of 14.6ºC. For top-down cracking, the maximum
stress occurs when one wheel of the dual wheel assembly is
placed touching the outer edge of the pavement at its corner
(load position L4) along with negative temperature
gradient. When the wheel load is touching the inner
edge/central longitudinal joint of the pavement (load
position L5) along with negative temperature gradient, the
stress is little less as compared to that at L4. This is true for
INDIAN HIGHWAYS
SEPTEMBER 2022
31
TECHNICAL PAPER
single, tandem and tridem axle loads on the pavement, as
observed from the FE analysis. The reduction in stress is
due to the continuity of pavement along the longitudinal
joint with some amount of load transfer due to aggregate
interlocking.
Table 1 Flexural Stresses for the Highest Single and
Tandem Axle Loads Combined with the Maximum
Temperature Gradients at Different Load Positions
Load
Position
L1
L2
L3
L4
L5
Axle
Type
Load
(kN)
Temperature
Gradient
(ºC)
Flexural
Stress
(MPa)
Single
160
+19.2
2.904
Tandem
330
+19.2
2.348
Single
160
+19.2
2.575
Tandem
330
+19.2
2.112
Single
160
+19.2
2.465
Tandem
330
+19.2
2.022
Single
160
-14.6
2.455
Tandem
330
-14.6
2.473
Single
160
-14.6
2.291
Tandem
330
-14.6
2.203
Remarks
BUC
TDC
Fig.3 Axle Load Positions for TDC
The critical stresses at load positions L1, L2 and L3 for BUC
and at load positions L4 and L5 for TDC for all single axle,
tandem axle and tridem axle loads are obtained from the FE
analysis. Table 1 gives the maximum flexural stresses
developed due to the highest single and tandem axle loads
(160 kN and 330 kN), combined with maximum positive or
negative temperature gradients for all load positions L1 to
L5. Fig. 4 (a) and (b) show typical pictures of the top and
bottom surfaces of the stress contour for the highest single
axle load of 160 kN placed at L1 along with positive
temperature gradient of 19.2ºC for BUC condition. The slab
curls upward (as seen from Fig. 4(a)) and the maximum
stress of 2.904 MPa occurs at the bottom of the slab below
the load (Refer Fig. 4(b)). Similarly, for the highest tandem
axle load of 330 kN and positive temperature gradient of
19.2ºC, the critical stress value is 2.348 kN for BUC at load
position L1.Stress values for other axle loads, smaller than
the highest single and tandem axle loads, are obviously less
than these stresses for BUC. For TDC, the maximum stress
is found to be 2.455 MPa for the highest single axle load of
160 kNat L4 when combined with negative temperature
gradient of 14.6ºC. The stress is 2.473 MPa for the highest
tandem axle load of 330 kN at L4 when combined with the
same negative temperature gradient. It has been observed
that the flexural stresses at all load positions are less than the
PQC flexural strength of 4.5 MPa and thus can be
considered as safe from flexural stress consideration.
32
INDIAN HIGHWAYS
SEPTEMBER 2022
(a) Top Surface
(b) Bottom Surface
Fig. 4 Stress Contours due to Single Axle Load of
160 kN Placed at Load Position L1 Combined
with Positive Temperature Gradient of 19.2ºC
TECHNICAL PAPER
4.3
Determination of Design Traffic
In conventional multi-lane highways with concrete
pavement, the panel dimension of 3.5 m is selected
considering the typical lane width. So, in this case, the lane
markings coincide with the longitudinal joints at centre and
also at the sides to segregate the lanes and the shoulder.
When the axle load is placed at the outer longitudinal edge in
between the two transverse joints (load position L1), the
stress becomes critical. Since very few vehicles are actually
moving along the edge of the pavement, therefore, the
design traffic has been recommended as 25% of the total
two-way traffic in the design guideline IRC:58-2015.
Though this is much higher, however, this has been
considered to be on the safer side. In case of multilane
highways with 9.0 m wide carriageway, there is a single
longitudinal joint at its centre. The panel size becomes 4.5 m
× 4.5 m, and the lane markings are not matching with the
longitudinal joints (Refer Fig.5). So, in this case the inner
edge or the central longitudinal joint practically becomes the
wheel path. As a result, a larger proportion of traffic (more
than 25% as mentioned in IRC:58-2015) need to be
considered for design traffic.
Fig. 5 Schematic of the Pavement Stretch for
Estimation of Lateral Placement of Vehicles
A 7-day sample traffic survey was carried out on a similar
road stretch with rigid pavement of dimension 4.5 m × 4.5 m
on both upstream and downstream. This was done to
understand the proportion of traffic moving along the central
longitudinal joint. Few lines (line A, B, C, D and E) were
drawn on the carriage way to estimate the lateral placement
of the wheels of the moving vehicles (Fig. 5). Line A, which
was 1.5 m away from the edge of the pavement, actually
represented the outer lane marking of the left lane. Line B
and line C were drawn on the carriage way parallel to line A.
Line D was the inner lane marking while Line E was the
outer lane marking for the right lane near the median. The
distance between these lines were decided keeping in mind
the centre line dimension between the two dual wheel
assemblies of 1.8 m for a typical axle (Maitra et al., 2009b).
Another consideration is the location of critical stresses due
to the placement of these dual wheels on the pavement. It is
to be noted that the flexural stress is maximum at load
position L1 and little less at load positions L2 and L3.The
flexural stress is significantly high even when the wheel is
little away within a distance of about 150 mm from the
edge/joint. However, the stress is reduced substantially
when the wheel is moved beyond 150 mm (IRC: 58-2015).
Therefore, considering these conditions, it is decided to
estimate the proportion of vehicles which are moving with
one wheel either touching the inner edge or central joint or
placed within a distance of 150 mm of it on either side,
which can produce higher stresses (but little less than the
maximum) on the pavement.
The wheel positions are now explained with respect to the
lines on the carriageway. (a) When any one wheel of a dual
wheel assembly is placed between lines A and B, the dual
wheels on the other side will be at least 150 mm away from
the central longitudinal joint. (b) When one wheel of the
dual wheel assembly is placed between lines B and C, the
dual wheels on the other side will be either on the central
longitudinal joint or within a distance of 150 mm on either
side of the joint. (c) When one dual wheel assembly is
placed between lines C and D, the dual wheels on the other
side will be more than 150 mm away from the central
longitudinal joint. (d) When the wheels of the dual wheel
assembly are placed between lines D and E, the wheels are
more than 150 mm away from the central longitudinal joint
and also from the edge of the pavement. Based on the wheel
positions between lines A & B, B & C, C & D and D & E,
the number of vehicles were determined from the sample
traffic survey. The results obtained from the sample traffic
survey are shown in Table 2.
From the traffic survey, it was found that about 50% of the
vehicles (with at least one wheel of a dual wheel set) were
travelling between Lines B and C. For this position of the
vehicles, the other dual wheel will be either on the joint or
within a distance of 150 mm on either side of the
longitudinal joint. This confirms that the central
longitudinal joint is practically the wheel path location for
majority of the vehicles for this type of pavement.
Considering a distance of 150 mm on both sides of the
longitudinal joint, it has been estimated that about 50% of
the total traffic in the predominant direction are actually
moving along the central longitudinal joint and are thus
responsible for fatigue damage. Therefore, the design
traffic has been considered here as 50% of the total traffic
in the predominant direction instead of 25% as given in
IRC:58–2015 for conventional pavement with standard
dimensions.
INDIAN HIGHWAYS
SEPTEMBER 2022
33
TECHNICAL PAPER
Based on the total two-way traffic of 59824270 during the
design period, and the average number of axles of 2.89 per
commercial vehicles, the total number of axle load
repetitions is thus calculated as 86446070 in the
predominant direction. Considering 50% of the total traffic
in the predominant direction, the design traffic is,
therefore, estimated as 43223035 for the project
road.flexural strength.The critical flexural stresses are
estimated for load positions L2 and L5 for BUC and TDC
conditions, respectively.
Table 2 Results of Traffic Survey on a Jointed Concrete Pavement with Panel Dimension of 4.5 m × 4.5 m
LHS
Sl.
No.
DATE
1
RHS
LINE
D-E
LINE
C-D
LINE
B-C
LINE
A-B
TOTAL
LINE
D-E
LINE
C-D
LINE
B-C
LINE
A-B
TOTAL
23-07-2020
8
19
28
2
57
12
12
30
2
56
2
24-07-2020
12
27
42
2
83
18
20
56
7
101
3
25-07-2020
8
36
35
4
83
14
28
41
5
88
4
26-07-2020
7
32
32
4
75
9
14
55
9
87
5
27-07-2020
10
28
22
6
66
14
24
32
4
74
6
28-07-2020
17
30
40
2
89
22
29
42
2
95
7
29-07-2020
11
17
18
1
47
12
8
18
2
40
73
189
217
21
500
101
135
274
31
541
15%
38%
43%
4%
100%
19%
25%
51%
6%
100%
TOTAL
PERCENTAGE
4.4
48%
Design Considerations for JPCP
Design of rigid pavement has been carried out considering
two criteria – critical stress criterion and fatigue criterion,
as per IRC: 58 - 2015.
From the FE analysis, critical stresses are obtained for all
axle load classes with single and tandem axles in
combination with maximum positive temperature
differential for bottom-up cracking condition for the three
load positions L1, L2 and L3. Similarly, for top-down
cracking condition, critical stresses are obtained for all axle
load classes with single, tandem and tridem axles in
combination with negative temperature differential for
load positions L4 and L5.All the stresses are found to be
less than the PQC flexural strength of 4.5 MPa as
mentioned in Section 4.2 of this Paper. Thus, the slab
thickness of 280 mm is considered to be safe against
flexural stress criterion.
For checking the adequacy of the pavement thickness against
fatigue, repetition of loads of each class of single and tandem
axles has been considered. The design traffic is estimated as
43223035, based on which the day time and night time axle
load repetitions are obtained as per IRC:58-2015. From the
frequency of different axle loads on the road, the expected
number of their repetitions are calculated for the design
period of 30 years. Allowable repetitions are determined
34
INDIAN HIGHWAYS
SEPTEMBER 2022
52%
based on the stress ratios. Stress ratios are estimated from the
critical flexural stresses for each axle load class and the PQC
The fatigue life consumed for each axle load class is
determined for both BUC and TDC conditions. The overall
fatigue damage is estimated by summing up the total fatigue
damages for BUC and TDC conditions and is obtained as
0.951for a PQC thickness of 290 mm. Since the value of
total fatigue damage consumed is less than 1.0, the assumed
PQC thickness of 290 mm is considered to besafe against
fatigue. Therefore, a thickness of 290 mm is adequate for
the pavement of dimension 4.5 m × 4.5 m with the given
traffic and soil conditions. Considering an additional 10
mm depth for texturing, the pavement thickness is
recommended as 300 mm for the project road stretch.
5.
CONSTRUCTION OF JPCP FOR THE
PROJECT ROAD
Based on the design, the rigid pavement is being
constructed with panel size of 4.5 m × 4.5 m × 300 mm
thickness for the subject project road on NH 151 in the
State of Gujarat. The construction is almost over
(construction period 2021-22) with major stretches
recently opened to traffic. Fig. 6 shows a photograph of the
pavement during construction with saw-cutting of joints
after concreting and Fig. 7 shows a photograph of one
stretch of the project road after construction.
TECHNICAL PAPER
panel dimensions as 4.5 m × 4.5 m. It is to be noted that the
stress charts and equations given in IRC guidelines
(IRC:58–2015) for the design of rigid pavements is
applicable only when the panel dimension is 3.5 m × 4.5 m.
The present approach provides a rational basis for the design
of rigid pavements with non-standard dimensions which
maybe adopted in the IRC design guidelines.
REFERENCES
1.
Fig. 6 Pavement Construction in Progress for the
Project Road
Fig. 7 A Stretch of Project Road after
Construction
6.
CONCLUSION
A rational approach has been suggested in the present work
for the design of rigid pavement with non-standard
dimensions. A finite element model has been developed for
the pavement with a single longitudinal joint at its centre and
analysis is carried out to obtain the critical flexural stresses
for BUC and TDC conditions. A specific traffic survey has
been carried out which indicates that the central longitudinal
joint practically becomes the wheel path location of large
number of traffic. Based on the proportion of traffic, the
design traffic has been considered as 50% of the total traffic
in the predominant direction of the road. The critical stress
criterion and fatigue criterion have been checked and a
design thickness is recommended for the project road with
IRC:58-2015. Guidelines for the Design of Plain Jointed
Rigid Pavements for Highways, Indian Roads Congress,
New Delhi.
2. PCA (1984). Thickness Design for Concrete Highway
and Street Pavements. Portland Cement Association.
3. IRC:15-2017. Standard Specifications and Code of
Practice for Construction of Concrete Roads, Indian
Roads Congress, New Delhi.
4. ANSYS Users' Manual, ANSYS Inc., Cannonsburg, PA,
2017.
5. Maitra, S. R., Reddy, K. S. and Ramachandra, L. S.
(2009a). “Experimental Evaluation of Interface Friction
and Study of its Influence on Concrete Pavement
response.” Journal of Transportation Engineering,
ASCE, Vol. 135(8), 563-571.
6. Westergaard, H.M. (1926). Stresses in Concrete
Pavements Computed by Theoretical Analysis, Public
Roads, Vol. 7, pp. 25-35.
7. Chintan Kumar, K. P.(2010). Theoretical Investigation
of Crack in Concrete Pavement with Tied Concrete
Shoulder, M. Tech Thesis, Transportation Engineering
Section, Civil Engineering Department, IIT Kharagpur.
8. Surya Teja, S., Reddy, M. A. and Pandey, B. B. (2017).
Analysis and Design of Concrete Pavements: A New
Approach, Indian Highways, Vol. 45, 12, pp. 37-42.
9. Maitra, S. R., Reddy, K. S. and Ramachandra, L. S.
(2015). “A Comprehensive Three-Dimensional Finite
Element Model for the Analysis of Jointed Concrete
Pavement.” Journal of the Indian Roads Congress, Vol.
75(4), pp. 73-81.
10. Maitra, S. R., Reddy, K. S. and Ramachandra, L. S.
(2010). “Load Transfer Characteristics of Aggregate
Interlocking in Concrete Pavement.” Journal of
Transportation Engineering, ASCE, Vol. 136 (3), 190195.
11. Maitra, S. R., Reddy, K. S. and Ramachandra, L. S.
(2009b)., “Load Transfer Characteristics of Dowel Bar
System in Jointed Concrete Pavement,” Journal of
Transportation Engineering, ASCE, Vol. 135(11), 813821.
INDIAN HIGHWAYS
SEPTEMBER 2022
35
TECHNICAL PAPER
DESIGN OF REINFORCED EARTH RETAINING WALL IN
SUBMERGED CONDITION
DR. S. K. BAGUI1
DR. A.K. SAHU2
VISHAL RATHORE SAURABH KUMAR4 SATYABROTO MITRA5
3
ABSTRACT
IRC:SP:102-2014 is presently used for R E Wall design in India and this guideline is silent for the design of RE Wall in
submerged condition. Therefore, based on this consideration, the present Paper presented the design procedure of RE Wall in
submerged condition and specification for reinforced filled material up to submerged depth plus 0.5 m and requirement of geofabric to avoid removal of reinforced material during certain drawdown of water to avoid failure of RE Wall in submerged
condition. Design procedure of RE Wall in submerged condition is presented in this Paper and recommended to use RE Wall in
submerged condition. Cost comparisons using RE Wall in submerged condition and RCC have been presented, Risk of using
RE wall submerged condition is also presented in this Paper. RE Wall in submerged condition can be designed and it is
technically viable but economically infeasible.
1.
INTRODUCTION
Overflow level is an important aspect for R E Wall design. If
the construction element is partially or substantially flooded,
floating forces must be considered in the design of Reinforced
Earth Retaining Wall. In this situation, a RE Wall will apply
lesser earth force/pressure on the ground soil. Hence FoS
against slipping and toppling will be decreased below the
permissible value. Therefore, a submerged condition disturbs
the complete immovability of a Reinforced Earth structure
and same should be accounted for in design.
RE walls along rivers and canals need to be assessed for the
supplementary force executed by hydrostatic force. This
extra load is due to the differential head across the RE
facing, that is, the difference in elevation between the water
external the wall and the water inside the coarse material in
the form of backfill of the structure. A lowest degree of
difference hydrostatic force equal to 10 cm of water is
generally adopted for design. The load is generally applied
at the high-water level.
In a certain drawdown condition, water in the short time
confined behind the RE wall panels can create an unstable
head condition and decrease the factor of safety in fine-
grained soil/ backfills.. To avoid the problems associated
with submergence, it is not compulsory to use completely
free draining (coarse) select backfill for such Reinforced
Earth structures. This backfill material provides the
additional advantage of high shear strength, increasing the
design factors of safety for sliding and reinforcement
pullout. Scour protection should be provided in front of the
structure, based on design scour depth.
2.
LITERATURE REVIEW
To basically assemble the water stockpiling cut-off of a
repository, it is essential to extend the height of the genuine
dam. This Paper depicts the arrangement method and
advancement challenges of a geosynthetic-strip-supported
precisely settled earth (MSE) divider used for the
augmentation of Los Vaqueros store dam in Contra Costa
County, CA. The site is arranged in a high seismic district,
and with their exhibited show under such circumstances, a
MSE divider with a most outrageous height of 15 m was
arranged and introduced to give a more broad dam top
while being fundamental for the barrier structure to extend
the dam stature by 10.4 m. Evaluation of the divider was
done utilizing AASHTO permissible burden Design
1 HOD, PMG Department, Intercontinental Consultants and Technocrats Pvt. Ltd, New Delhi, Email : [email protected]
2 Professor, Department of Civil Engineering, D.T.U., New Delhi.
3 Deputy Manager,
4 Deputy Manager,
Intercontinental Consultants and Technocrats. Pvt. Ltd, New Delhi
5 Assistant Manager,
}
36
INDIAN HIGHWAYS
SEPTEMBER 2022
TECHNICAL PAPER
procedure and concentrates completely overwhelmed and
fast drawdown conditions. The divider region estimation
had a trapezoidal allocation using variable lengths of soil
backing to avoid conflicts with the dam mud focus and the
current stone back face. High constancy polyester
GeoStrapTM (geosynthetic strip) was used for the dirt
support for the practical clarification of fortitude as
indicated by the variable soil support lengths introduced by
site space limits. To restrict the hydrostatic strain applied to
the MSE divider, significantly penetrable rock trim was
used as select fill in the upheld volume. This paper
similarly analyzes advancement challenges related with
the use of rock refill, the presence of a stone back face and
earth center behind the divider, the nonuniform lengths of
soil backing and keeping a vertical divider standing up to
(Fransiscus et.al. 2013).
Looking at the current circumstance of extension in people
and solicitation of present day lifestyle, attainable civil
strong waste (MSW) the board may reliably remain an
issue of concern. The critical objective of this audit is to use
existing Pirana landfill MSW (Ahmedabad, Gujarat) as fill
material for built up earth (RE) divider with uniaxial
geogrid support and survey its heap relocation
characteristics under nonstop steady loadings. To fulfill
this objective, sand, MSW, sand sandwiched among MSW,
and mix 1(sand) :3 (MSW) composites were used as top off
material under dry condition. Sidelong movements were
assessed at 4 regions on going up against board (divider)
for each pile increments as 20%, 40%, of most prominent
theoretical weight. For the most capable MSW composite,
the effect of level of immersion and circulation of molecule
size was assessed and evaluated using movement and earth
pressure speculations. From results and examination it is
assumed that MSW can be feasibly used as top off material
in RE divider reliant upon MSW-support affiliation and
flexible strain closeness of help expecting part in load
dispersing under most prominent loadings (Kinjal 2019).
The help life of precisely balanced out earth (MSE)
dividers depends upon the speed of utilization of the
metallic fortresses used in their turn of events. A system
was expected to screen and check the consumption speed
of invigorated steel in MSE dividers with a conductivity
sensor joined with lab electrochemical techniques. The
fluid conductivity of six coarse-grained top off soils going
through either wet-dry cycles or under brought down
conditions were assessed reliably for up to 120 weeks. The
conductivity of the filter alcohol appears to be encouraging
to screen the utilization rate in spite of the way that the
expected disintegrated thickness was not by and large the
veritable dissolved thickness assessed with an analyzing
electron microscope (Arturo et.al. 2020).
This Paper presents the eventual outcomes of a numerical
assessment on the effect of precipitation on the
presentation of a supported earth divider. A movement of
limit amicability based inclination sufficiency assessments
inside the construction of unsaturated shear strength,
joined with transient infiltration examinations considering
genuine precipitation record were performed to assess the
effect of precipitation on the display of the developed earth
divider to the extent that part of prosperity. A parametric
report was in addition coordinated on the precipitation
power. The results showed that the built up divider
trustworthiness, to the extent that part of prosperity, could
be by and large reduced when subject to precipitation on
account of reduction in shear strength of top off achieved
by the diminishing in matric attractions. Moreover shown
is that there appears to exist an essential precipitation
volume past which no further colossal reducing in the
variable of prosperity occurs. Practical ideas on the
disclosures of this audit will similarly be inspected (Yoo
2011).
A strategy for the inward plan of built up soil dividers
reliant upon working tensions is made and surveyed using
assessments from five full scale structures containing an
extent of help types. It is shown that, overall, the stiffer the
help structure and the higher the nerves started during
compaction, the higher are the pliable anxieties that ought
to be gone against by the fortifications. Exceptional
components of this system, diverged from by and by used
built up soil divider plan methods, are that it might be
applied to a wide scope of help structures, backing and soil
solidness properties are considered, and decorate
compaction stresses are thought about unequivocally. The
method can be applied either experimentally or using
arrangement diagrams. An arrangement model is fused
(Mauricio and James 1994).
For structures along streams and streams, a base
differential hydrostatic strain identical to 1.0 m of water
will be considered for plan. This heap will be applied at the
high-water level. Powerful unit loads will be affected by
tide or stream instabilities could require that the divider be
planned for quick drawdown conditions, which could
achieve differential hydrostatic strain amazingly more
unmistakable used in the assessments for internal and
outside sufficiency beginning at levels just under the usage
of the differential hydrostatic pressure 1 m water
significance of course rapidly draining decorate material,
for instance, shot stone or open assessed coarse stone can
be used as top off. Decorate material assembling the
graduation essentials in the AASHTO LRFD Bridge
Construction Specifications for MSE structure top off isn't
seen as speedy draining. (AASHTO LRFD 2017).
Starting around 1994, the Japan Railway has assembled
various full tallness going up against GRS range
projections and docks Kanazawa et al., 1994; Tatsuoka et
al., 1997) using an unbendable standing up to GRS divider
INDIAN HIGHWAYS
SEPTEMBER 2022
37
TECHNICAL PAPER
structure made by Tatsuoka and his accomplices at the
University of Tokyo. These GRS span supporting
constructions have been created in two stages. The
essential stage incorporates fostering a wrapped-shaded
GRS divider with the aide of gabions, and the ensuing stage
incorporates projecting set up a full-height upheld
significant investigating the wrapped face. Field
assessment has shown that these developments
experienced little mutilation under help stacks and have
performed clearly better compared to normal upheld
concrete holding dividers and projections in the 1995 Japan
Great Hansin seismic quake that purposeful 7.2 on the
Richter scale (Tatsuoka et al., 1997). Most lately, Tatsuoka
and his accomplices encouraged a preload prestress
procedure for additional created execution of the GRS
bridge supporting structures (Tatsuoka et al., 1997;
Uchimura et al., 1998). Despite their thriving, the rigid
going up against GRS span supporting designs have
tracked down applications simply in Japan, for the most
part because of their more prominent cost and longer
improvement time stood out and GRS dividers from
versatile facings.
The six projections are the Vienna railroad dam in Austria,
the New South Wales GRS range projections in Australia
(Won et al., 1996), the Black Hawk length projections in
Colorado (Wu et al., 2001), the Founders/Meadows length
projections in Colorado (Abu-Hejleh et al., 2002), the
Feather Falls Trail range projections in California (Keller
and Devin, 2003), and the Alaska range projections in
Alaska (Keller and Devin, 2003).
Each GRS projection contained a two-level GRS mass with
two square footings on the lower level and a strip balance
on the upper level. The square footings on the West
projection are implied as Footings #1 and #4, and the
square footings on the East projection are suggested as
Footings #2 and #3. The GRS length projections were
based on a solidified soil. The thicknesses of the lower level
developed soil mass under Footings #1 and #4 were,
independently, 4.5 m and 1.5 m; and 7.5 m and 1.5 m under
Footings #2 and #3, separately. The lower part of the GRS
projection was embedded in the ground, while the upper
part was over the ground. Simply the part over the ground
was created with rock going up against. The more than 14
ground piece of the projection had different heights,
fluctuating from 1.0 m to 2.7 m for the West projection; and
from 1.0 m to 5.4 m for the East projection. The thickness
of the upper level upheld soil mass was 1.8 m for the two
projections. The upper level upheld soil mass was
attempted to assist the strip with adjusting and the system
slant. The projections were created with the on the spot soil,
appointed SM-SC per ASTM D2487, and developed with
layers of a woven geotextile at vertical isolating of 0.3 m.
The polypropylene woven geotextile had a wide width
38
INDIAN HIGHWAYS
SEPTEMBER 2022
inflexibility of 70 kN/m in both machine and cross machine
direction at 18% strain, per ASTM D 4595 (Adams 1997).
A full-scale length moor was created and load attempted at
the Turner-Fairbank Highway Research Center, FHWA, in
McLean, Virginia. The dock was 5.4 m high and 3.6 m by
4.8 m at its base. The dock was maintained on an upheld soil
foundation (RSF). The RSF involved compacted road base
and three layers of biaxial geogrid support, isolated 0.3 m
isolated. The RSF was 1.2 m significant, over a space of 7.3
m by 7.5 m. Figs. 2-9 shows the cross-portion of the GRS
range wharf. The wharf was created with specific
significant squares as the standing up to and was upheld
with a polypropylene woven geotextile, Amoco 2044, at
vertical separating of 0.2 m. The decorate was designated
an overall looked into rock. The best dry unit weight was 24
3
kN/m , per AASHTO T-99, with the ideal moistness
content being 5.0 percent. The typical compaction in the
field was around 95% of the best dry density (Adams 1997).
2.1
Summary of Literature Review
i.
In order to minimize the hydrostatic pressure applied
to the MSE wall, highly permeable gravel backfill was
used as select fill in the reinforced volume for dam
embankment construction.
ii.
For the most efficient MSW composite, the effect of
degree of saturation and particle size characterization
was measured and evaluated using displacement and
earth pressure theories. It was established that MSW
can be successfully recycled as fill material in
Reinforced Earth.
iii. For structures along rivers and streams, a minimum
differential hydrostatic pressure equal to 1.0 m of
water shall be considered for design and open graded
backfill was used for free draining condition.
iv.
A method for the internal design of reinforced soil
walls based on working stresses is developed and
evaluated using measurements from five full scale
structures containing a range of reinforcement types
3.
OBJECTIVE AND SCOPE OF THE PRESENT
STUDY
IRC:SP:102-2014 is presently used for R E Wall design and
this guideline is silent for the design of RE Wall for
submerged condition. Therefore, based on this consideration,
there is a need of study for the development of up gradation of
design procedure for submerged condition. Based on this
objective, following scopes of the work have been finalized
in this present study:
i.
ii.
Literature review of RE Wall design in partially
submerged condition
Requirement of special grading of granular material
TECHNICAL PAPER
for reinforced fill for submergence area and
requirement of geofabric for warping reinforced
material to avoid loss of the material during certain
drawdown and draining time.
iii. Modification of theoretical design procedure of RE
Wall for partially submerged condition.
iv. Case study analysis
v.
4.
Discussion and Conclusion
GRADING OF REINFORCED FILL MATERIAL
IN SUBMERGED CONDITION
In a rapid drawdown situation water temporarily trapped
behind the wall panels can create an unbalanced head
condition and reduce the factor of safety in relatively finegrained (sandy to silty) backfills and there is a chance of
removing fine soil in this condition. To avoid this problem
it is suggested to adopt fully permitted draining aggregate
material backfill for such Reinforced Earth structures. This
fill material has high shear strength parameters that give
higher design factors of safety for slipping and
reinforcement pullout.
Alternately, No. 57 stone material, as specified in
AASHTO M 43, may be provided as reinforced filling
material for the entire reinforced zone of the wall upto the
maximum depth of submergence of the wall. A
geocomposite as filter media may be provided at the
interface of the No. 57 coarse aggregate and reinforced
backfill above it, at the interface of the retained backfill
behind it, and at the interface of the coarse gravel and
subgrade beneath it. The geotextile should meet the
filtration and survivability criteria as mentioned Section
700 of MORT&H 2013. Adjoining sections of geotextile
filter/separator shall be overlapped by a minimum of. 3 m.
An example detail is shown in Fig.1 [FHWA(Page 5-16).]
It is not generally possible to compact aggregate material,
but can be properly oriented with compaction equipment.
This is particularly important when using # 57 stone under
flexi-pave surfaces.. Before placing the stone, a geotextile
fabric is often used as a soil separator between stone and
layer below geo-fabric to reduce potential loss of the stone
in future. The void between open graded #57 stone,
aggregate allow air water to pass pass through the void.
Compaction testing using nuclear gauge is not possible. It
shall be compacted using plate compactor, jumping jack or
other vibratory devices. Number of pass will be determined
based on trial and taking settlement after 7 days of
compaction. Grading is mentioned below (AASHTO M
43).
Table 1 Grading of Free Draining Material
5.
Sieve Size (mm)
Passing ( %)
37.5
100
26.5
95-100
13.2
25-80
4.75
0-10
75 micron
0-5
MODIFICATION OF R E WALL DESIGN
Generally bulk density is used to determine the pressure
behind the RE Wall. In the case of submerged condition
earth pressure will be designed considering two stages i.e.,
contribution of bulk density and submerged density and
pressure diagram will be used to calculate for RE Wall
analysis.
6.
CASE STUDY
For validate objectives and scopes of present study a
project has been considered for RE Wall Design. The input
is tabulated in Table 2.
Factor of Safety (FoS) for various cases(Loading
combinations A, B and C) are calculated using a standard
excel sheet and presented in Table 2. FoS for bearing,
overturning and sliding are calculated and these are
presented in in Fig. 2. Ground water table varies from 0.0 m
to 5.0 m above ground. FoS values are considered 1.4, 1.2
and 1.2 as per Section 5.1 of IRC:SP:102-2014 for the
cases of bearing and tilt failure, sliding and overturning
which are mostly effected RE Wall in submerged
condition.
Loading combinations A.B and C are mentioned in
IRC:SP:102-2014.
Fig. 1 Typical RE Wall in Submerged Condition
Form these three figures (Fig.2 a to Fig.2c); it is generally
observed that FoS values are reducing with increasing
depth of water.
INDIAN HIGHWAYS
SEPTEMBER 2022
39
TECHNICAL PAPER
Table 2 Design Input of RE Wall
40
INDIAN HIGHWAYS
SEPTEMBER 2022
TECHNICAL PAPER
This is due to the partial Safety of factor values are lower and
higher as per Table 3 of IRC:SP:102-2014 (1.5 is considered
for, lateral pressure and traffic load and 1.0 for dead load).
From Fig.2c, it is observed that FoS values are decreased
with increasing depth of water but all values are above
limiting values of 1.4 and 1.2 except FoS internal stability
falls below 1.2 for water depth above 2.5 m. Therefore,
loading combination is critical for the case of internal
stability. This is due to the partial Safety of factor values are
lower and higher as per Table 3 of IRC:SP:102-2014 (1.0 is
considered for, lateral pressure , traffic load and dead load).
Fig. 2a Relationship between Ground Water Level
and FoS for Loading Combination A
Generally,75 micron passing 15% and it may be increased.
In submerged condition, there is a chance of removing fine
due submerged condition and case will be serious for
sudden draw down condition and causes of failure of RE
wall due to loss of friction force i.e., failure due to internal
stability will occur.
To avoid this situation, provision of granular aggregate
layer with grading as mentioned in Table 1 will be choice.
Density of this layer is more than that of soil. Depth of
aggregate layer will be equal to High Flood Level
(HFL)+0.3 m. This granular layer shall be warped with
geocomposite to avoid removing of granular material due
submerged and sudden draw down condition.
Fig. 2b Relationship between Ground Water Level
and FoS for Loading Combination B
7.
ANALYSIS USING GRANULAR BACKFILL
Assuming bulk density of granular layer 23kN/m3, analysis
has been carried out and FoS values recalculated and
graphs are prepared. In this case, reinforced is consisted of
two types i.e., soil and aggregate. Phai value of aggregate
in submerged condition will be around 350 or more. Similar
graph like Fig. 2 is found and Case B loading is critical as
shown in Fig. 3.
Fig. 2c Relationship between Ground Water Level
and FoS for Loading Combination C
From Fig. 2a, it is observed that FoS values are decreased
with increasing depth of water but all values are above
limiting values of 1.4 and 1.2.Therefore, loading combination
is not critical. This is due to the partial Safety of factor values
are higher as per Table 3 of IRC:SP:102-2014 (1.5 is
considered for dead load, lateral pressure and traffic load).
From Fig. 2b, it is observed that FoS values are decreased
with increasing depth of water but all values are above
limiting values of 1.4 and 1.2 except FoS internal stability
falls below 1.2 for water depth above 2.0 m. Therefore,
loading combination is critical for the case of internal stability.
Fig.3 Relationship Ground Water Level and FoS for
Loading Combination B
It is found that strip length is increased to increase depth of
water. Variation of reinforcement is shown in Fig.4. Best fit
curve has been plotted and presented in Equation 1.
Strip Length=0.9315*Water Depth+5.0
INDIAN HIGHWAYS
SEPTEMBER 2022
(1)
41
TECHNICAL PAPER
R2 value is calculated and found to be =0.973 which
indicated a good correlation between depth of water in RE
Wall and strip length of RE Wall.
Mechanically Stabilized Earth (MSE) wall design analysis
has been carried out with the respective strength and length
Geo-strip without submergence condition and FOS is
found to be 1.31. In the second case analysis, the water
pressure effect included in the analysis considering the
water pressure 5m from bottom of RE wall and FOS is
found to be 0.96 which is unsafe in nature. Again analysis
has been carried out for stabilizing the wall by increasing
the strength and length as mentioned in Table 3 and FOS
value is 1.33. Hence it can be can concluded that increasing
the length and strength of Geostrips tends to stable the
MSE wall in submerged condition by conducting analysis
using Geo5 software.
Final output for different cases using Geo5 is shown in
Fig.5 to Fig.7.
Fig.4 Length of Reinforcement Vs Submerged
Depth of RE Wall
Table 3 Without and With Submergence used Geostrap Properties in Software
8.
Without submergance
With submurgance with water effect 5m from bottom
Height from
bottom
Length
Type
Strength
Length
Type
Strength
0
7.7
Techstrap 50
50
13
Techstrap 150
150
0.8
7.1
Techstrap 40
40
13
Techstrap 150
150
1.6
7.1
Techstrap 30
30
12
Techstrap 100
100
2.4
7.1
Techstrap 30
30
12
Techstrap 100
100
3.2
7.1
Techstrap 30
30
10
Techstrap 100
100
4
7.1
Techstrap 30
30
10
Techstrap 100
100
4.8
7.1
Techstrap 30
30
10
Techstrap 100
100
5.6
7.1
Techstrap 30
30
7.1
Techstrap 30
30
6.4
7.1
Techstrap 30
30
7.7
Techstrap 30
30
7.2
10.25
Techstrap 30
30
10.25
Techstrap 30
30
COST COMPARISONS
RE Wall in submerged condition, RE Wall without
submerged condition and RCC Wall in replacement of RE
Wall is calculated per m2 and presented in Table 4. Based
on cost comparisons, RE Wall in submerged case is not
economically /financially viable. Therefore, Conventional
Retaining wall is preferable.
Table 4 Comparisons of RE Wall Cost in Submerged Case
Depth of Water
(m)
RE Wall without
Granual Fill(Rs)
RE Wall with
Granual Fill(Rs)
RCC(Rs)
2.75
4000
10070
12000
3.00
4000
10585
12000
4.00
4000
12650
12000
4.50
4000
13680
12000
5.00
4000
14715
12000
42
INDIAN HIGHWAYS
SEPTEMBER 2022
Remarks
It is observed that RE wall in submerged
condition height 4 m or more is economically
unfeasible and RCC Retaining wall is
recommended.
TECHNICAL PAPER
Fig. 5 Slope Stability Verification without Submergence
Fig. 6 Slope Stability Verification with Submergence upto 5m from Bottom
INDIAN HIGHWAYS
SEPTEMBER 2022
43
TECHNICAL PAPER
Fig. 7 Slope Stability Verification with Submergence upto 5 m from Bottom after Increasing Geostrip Lengths.
9.
ASSOCIATED RISK FOR SUBMERGED
CONDITION
Design and construction is very important for RE Wall in
submerged condition. Reinforced material for submerged
depth should be free from fine material (free from 75 micron
passing material). The compaction is important and
impossible at 95 % MDD. Actual achieve able density shall
be considered for RE Wall design. Geofabric warping
material should not be damaged so that no material will be
removed. The system will be failed if any materiel removed
during rapid drawdown case. Therefore, there will involve
failure of risk of RE Wall. Cost for the provision of RCC
Wall shall be checked. Final proposal should be considered
based on cost comparison and involvement of risk.
10.
DISCUSSIONS AND CONCLUSIONS
This study is presented the technical consideration of RE Wall
in submerged condition and cost comparison of RE Wall in
submerged condition. Based on case study, RE Wall failures
occurs in flooded situation due to reducing factor of safety
internal sliding. RE wall in submerged condition involves
huge cost involvement. This study presents a case study and
findings are specific and limited. Based on case study,
following conclusions may be drawn as presented here in.
44
INDIAN HIGHWAYS
SEPTEMBER 2022
i.
Granular fill shall be provide up to depth HFL+0.3 m.
Grading of fill material as mentioned in Table 1 may
be used. Fill material shall be warped with geocomposite to avoid removal of material.
ii.
Design of RE Wall is complicated. Vertical Dead load
and lateral pressure will be calculated accordingly.
Two types reinforced fill material will be used and
weighted k value may be used for loading calculation.
iii.
From Figs. 2 & 3, it is found that failure of RE Wall
occurs due to internal sliding and reinforcement length
will be increased to avoid failure against sliding.
iv.
From Fig.4, it is found that length of strip is increasing
with increasing depth of submergence and it increases
cost of RE Wall.
v.
From Table 2, it is generally observed that cost
comparison is required to adopt RE Wall in
submerged condition.
vi. From Fig.1, it is found that scour protection is also
required to avoid failure of RE Wall and it involves an
additional cost
vii. From Fig.2 and Fig.3, it is generally observed that
factor of safety decreases with increasing depth of
submergence.
TECHNICAL PAPER
viii. Performance of RE Wall in submerged condition is
required in Indian condition. A research project/
experimental/laboratory study is required to verify
RE Wall theory in submerged condition.
REFERENCES
1.
2.
3.
4.
5.
6.
7.
Fransiscus S. Hardianto, Robert Lozano John E. Sankey, and
David K. Hughes (2013). “Geosynthetic-Strip Reinforced MSE
Wall for Dam Expansion”Geo-Congress 2013, March 3-7, 2013 |
San Diego, California, United States.
Kanjal H. Gajjar; Manish V. Shahand Alpa J.Shah (2019).”
Performance Evaluation of Municipal Solid Waste as a
Sustainable Backfill Material in REWall”. Eighth International
Conference on Case Histories in Geotechnical Engineering,
March 24–27Philadelphia, Pennsylvania,PP328-335
Arturo Bronson, Carlos Castillo, Jesus Hinojos; and Soheil nazarian.
(2020). “Relating Corrosion of Mechanically Stabilized Earth
Reinforcements with Fluid Conductivity of Backfill Soils”Journal of
Materials in Civil Engineering, November 2020 Volume 32, Issue
11Online publication date: SEPTEMBER 26, 2020.
C. Yoo,(2011). “Effect of Rainfall on Performance of Reinforced
Earth Wall “.Geo-Frontiers 2011: Advances in Geotechnical
Engineering (1852 - 1861), Geo-Frontiers Congress 2011, March
13-16, 2011 | Dallas, Texas, United States,https://doi.org/10.1061
/41165(397)189.
Mauricio Ehrlich, and James K. Mitchell(1994). “Working Stress
Design Method for Reinforced Soil Walls”.Journal of Geotechnical
Engineering April 1994 Volume 120, Issue 4 (625 - 645).
AASHTO LRFD (2017). Bridge Design Specifications, Eighth Edition.
Japan Railway (JR) Technical Research Institute, “Manual on
Design and Construction of Geosynthetic-Reinforced Soil
Retaining Wall.” (1998) 118 pp.
8.
9.
10.
11.
12.
13.
14.
15.
Kanazawa, Y., Ikeda, K., Murata, O., Tateyama, M, and Tatsuoka, F.,
“Geosynthetic-Reinforced Soil Retaining Walls for Reconstructing
Railway Embankment at Amagasaki.” Recent Case Histories of
Permanent Geosynthetic-Reinforced Soil Retaining Wall (Tatsuoka
and Leshchinsky, editors) A. A. Balkema Publishers, Rotterdam, The
Netherlands (1994) pp. 233–242.
Tatsuoka, F., Uchimura, T., and Tateyama, M., “Preloaded and
Prestressed Reinforced Soil.” Soils and Foundations, Vol. 37, No.
3 (1997) pp. 79–94.
Uchimura, T., Tatsuoka, F., Tateyama, M., and Koga, T.,
“PreloadedPrestressed Geogrid-Reinforced Soil Bridge Pier.”
Proceedings 6th International Conference on Geosynthetics,
Atlanta, Georgia, Vol. 2 (1998) pp. 565–572
Won, G.W., Hull, T., and De Ambrosis, L., “Performance of a
Geosynthetic Segmental Block Wall Structure to Support Bridge
Abutments.” Earth Reinforcement (Ochiai, Yasufuku, and
Omine, editors) A. A. Balkema Publishers, Rotterdam, The
Netherlands, Vol. 1 (1996) pp. 543–548.
Wu, J.T.H., “Revising the AASHTO Guidelines for Design and
Construction of GRS Walls,” Report No. CDOT-DTD-R-200116, Colorado DOT (2001) 148 pp.
Keller, G. R. and Devin, S.C., “Geosynthetic-Reinforced Soil
Bridge Abutments.” Transportation Research Record 1819, Vol. 2
(2003) pp. 362–368
A b u - H e j l e h , N . , Z o r n b e r g , J . G . , Wa n g , T. , a n d
Watcharamonthein, J., “Monitored Displacements of Unique
GeosyntheticReinforced Soil Bridge Abutments.” Geosynthetics
International, Vol. 9, No. 1 (2002) pp. 71–95.
Adams, M.T., “Performance of a Prestrained Geosynthetic
Reinforced Soil Bridge Pier.” Mechanically Stabilized Backfill,
Wu, editor, A. A. Balkema Publishers, Rotterdam, The
Netherlands, (1997) pp. 35–53.
INDIAN HIGHWAYS
SEPTEMBER 2022
45
NOTIFICATION
Notification No. 48
Amendment No. 1/IRC:SP:59-2019/June, 2022 (Effective from 1st September, 2022)
To
IRC:SP:59-2019 “Guidelines for Use of Geosynthetics in Road Pavements and Associated Works” (First Revision)
S.
No.
1
Clause No.
Page No.
Annexure IV Annexure IV Worked-out Examples
Example 1
Illustrating the Design Methods
(Page No. 85)
Example 1: Design the pavement for
construction of a new flexible pavement
with the following data:
Input data:
Design traffic: 50 msa
Subgrade CBR = 6%
2
Example 1
(Page No. 85)
Read
For
Solution:
Annexure IV Worked-out Examples Illustrating
the Design Methods
Example 1: Design the Geosynthetics Reinforced
Flexible Pavement using LCR and MIF Methods
with the following data:
Input data:
Design traffic: 100 msa
Effective Subgrade CBR = 5%
Solution:
New Section Added
Section A- Design of Conventional Pavement
Section using IRC 37: 2018
Design Traffic = 100 msa
Effective Subgrade CBR = 5%
By iteration, the following thicknesses are
arrived at by using IITPave (IRC:37-2018)
Bituminous Concrete (BC) = 50 mm
Dense Bituminous Macadam (DBM) = 150 mm
Base (WMM) = 250 mm
Granular Sub-Base (GSB) = 250 mm
3
Example 1
i.
(Page No. 85)
Design resilient modulus of the i.
compacted subgrade
MR (MPa) = 10 × CBR ; for CBR 5
= 17.6 × (CBR)0.64 ; for CBR > 5
Where M R = Resilient modulus of
subgrade soil
MR subgrade =17.6×60.64= 55.4 MPa
Determination of Resilient Modulus of the
compacted subgrade as per IRC 37: 2018
Resilient Modulus of subgrade (in MPa)
MRS = 10 x CBR (For CBR< 5%)
(Equation 6.1 of IRC 37: 2018)
Where MRS = Resilient Modulus of subgrade
soil
MRS subgrade = 10 x 5 = 50 MPa
ii. Thickness of unreinforced granular
layers: For design traffic of 50 msa and
ii. Thickness of unreinforced granular layers:
obtained CBR of 6 per cent, the thickness
For design traffic of 100 msa and effective
values are taken as below with reference
CBR of 5 per cent, the thickness values have
to design plates (Assume Plate 4) from
been arrived by iteration as given below with
IRC: 37.
reference to design from IRC: 37.
Thickness of granular base (D2) = 250 mm,
Thickness of granular sub-base (D3) = 260 mm Bituminous Concrete (BC) = 50 mm
Dense Bituminous Macadam (DBM) = 150 mm
MR_G =0.2 x h 0.45 x MR_subgrade
Where h= thickness of granular base and subThickness of Granular Base, WMM (D2) = 250 mm,
base layers, mm
The thickness of granular sub-base (GSB)
Therefore, resilient modulus of granular layer
(D
3)=250 mm
= 0.2 × (510)0.45 × 55.4= 183.20 MPa
46
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
Thickness of proposed bituminous layer with iii. Resilient Modulus of Granular Layers VG 40 bitumen with bottom DBM layer
GSB+GB(WMM) (in MPa)
having air void of 3 per cent (0.5 per cent to
MRGRAN = 0.2 x HGRAN0.45 x MRS
0.6 per cent additional bitumen over OBC)
= 0.2 x (250+250)0.45 x 50
over WMM and GSB mm at reliability of 90
MRGRAN = 163.88 MPa
per cent.
VG 40 grade Bitumen shall be considered in the
design with the following properties as per clause
no. 9.2 of IRC 37: 2018.
Va = 3 % (volume of air void in the mix used in the
bottom bituminous layer)
Vbe = 10.2 % (volume of effective bitumen in the
mix used in the bottom bituminous layer),
Reliability of 90 %
iv. Resilient Modulus of Bituminous Layers BC+DBM (in MPa)
MRM = 3000 MPa
Determination of permissible strains
1. Determination of permissible rutting strains
(εV):
2
Determination of permissible fatigue strain
(εt):
Based on these permissible strains, the
thicknesses of the conventional and reinforced
pavement shall be determined and the procedure
for the same is given below.
Analysis of Conventional Flexible Pavement
SectionBy entering the above thicknesses and MR values of
pavement layers in IITPave software for wheel load
of 20000 N, tyre pressure of 0.56 MPa and dual
wheel set, the induced horizontal tensile strain is
determined beneath the bituminous layer (BC+DBM)
and vertical compressive strain is determined over the
subgrade as per the procedure given in IRC 37: 2018.
INDIAN HIGHWAYS
SEPTEMBER 2022
47
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
Fig. IV-1 Screenshot of IIT Pave for
Horizontal tensile strains and vertical
compressive strains induced in pavement
layers for unreinforced section
From the above output of IIT Pave, it is observed
that the induced strains are less than the
permissible strains as shown below.
The induced maximum horizontal tensile strain
148.8 x 10-6 < 151.7 x 10-6
The induced maximum vertical compressive
strains= 261.3 x 10-6 < 319.0 x 10-6
Thus the Conventional flexible pavement design
is safe from rutting and fatigue strain criteria.
4
5
Example 1
(A) Design calculations of bitumen
(Page No. 85) pavement with geogrid reinforced granular
base and subbase layers using LCR of
geogrid
Example 1
(Page No.
85 & 86)
Reducing thickness of pavement section
In this case the effect of reinforcement is
shown as the reduction in the pavement
section thickness.
i.
ii.
iii.
iv.
Design Traffic = 50 msa
Subgrade CBR = 6 per cent
Reliability = 90 per cent
Resilient Modulus of Subgrade (MR):
MR (MPa) = 17.6×60.64= 55.40 MPa
Resilient modulus of Subbase and Base
layers:
Granular sub-base thickness (MR_GSB) = 260 mm
MR_GSB = 0.2 x h0.45 x MR_subgrade
Where h= thickness of granular sub-base
layer, mm
MR of unreinforced subbase layer = 0.2 ×
(260)0.45 × 55.4 = 136 MPa = 19724.624Psi
Granular Base thickness = 250 mm
MR_GB = 0.2 x h0.45 x MR_GSB
Where h= thickness of a granular base
layer, mm
48
INDIAN HIGHWAYS
SEPTEMBER 2022
Section B- Design calculations Flexible
Pavement with Geogrid reinforced granular
base layer using Layer Coefficient Ratio (LCR)
Method
Deleted
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
MR of unreinforced base layer = 0.2 × (250)0.45
× 136 = 327MPa = 47426.118Psi
Resilient modulus of Bituminous Mixes =
3000 MPa = 435102 Psi
v. Structural layer coefficient of each layer:
Layer coefficient for bituminous layer (a1)
= 0.171 x (LN (MR))-1.784
= 0.171 x (LN (435102))-1.784=0.436
(a) Structural Layer coefficient for base
layer shall be taken from the equations
given in AASHTO 1993.
Structural layer coefficient for base layer
a2 = 0.249× (log10MR_BC) – 0.977 = 0.249 ×
(log10 47426.118)-0.977 =0.188
(b) Structural layer coefficient for subbase
layer
a3 = 0.227(log10MR_SB) – 0.839 = 0.227 × (log10
19724.624)-0.839 = 0.136
Therefore,
Layer coefficient for base layer (a 2 )
= 0.188
Layer coefficient for sub base layer (a3) = 0.136
vi. Layer Coefficient Ratio: Layer coefficient
for geogrid is taken on the basis on the
laboratory tests/filed tests; or it can be
provided by the manufacturer.
(LCRbase) for geogrid used in base layer = 1.4
(LCRSubbase) for geogrid used in sub-base
layer = 1.61
6
7
Example 1
(B) Modified layer thickness values for By iteration, the following thicknesses are arrived
reinforced sections by IITPAVE:
by using IITPave software
(Page No. 86)
Thickness of sub-base layer =180 mm
Bituminous Concrete (BC) = 50 mm
Thickness of base layer = 160 mm
Dense Bituminous Macadam (DBM) = 115 mm
Granular Base (WMM) = 200 mm
Granular Sub-Base (GSB) = 300 mm
For pavement design with Geogrid using LCR
method, the Base and GSB layers are
considered separately for calculation of MR
values as per Section 8.1 of IRC 37:2018, unlike
conventional method where both GSB and Base
are considered together.
Example 1
Page No. 86
Resilient modulus of reinforced Subbase Determination of Resilient Modulus as per
and Base layers
IRC 37: 2018
Granular sub-base thickness = 180 mm
Resilient Modulus of subgrade (in MPa)
INDIAN HIGHWAYS
SEPTEMBER 2022
49
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
MR_GSB = 0.2 x h0.45 x MR_subgrade
MRS = 10 x CBR (For CBR< 5%)
(Equation
6.1 of IRC 37: 2018)
Where h = thickness of granular sub-base
MRS = 10 x 5 = 50 MPa
layer, mm
MR of reinforced subbase layer = 0.2 × In the LCR method of design, Resilient Modulus
of the Geogrid reinforced layers improves. The
(180)0.45 × 55.40 = 115 MPa = 16678.91Psi
layer
within which the Geogrid is placed, the
Granular Base thickness = 160 mm
corresponding
structural layer coefficient(s)
MR_GB = 0.2 x h0.45 x MR_GSB
is/are modified by multiplying it by the
Where h = thickness of a granular base layer, corresponding layer coefficient ratios. Resilient
Modulus is determined in terms of PSI. The
mm
calculations
for structural layer coefficients are
MR of reinforced base layer = 0.2 × (160)0.45 × given after the Resilient Modulus computations.
115= 225 MPa = 32632.65 Psi
Resilient Modulus of Granular Sub-Base (in PSI)
MRGSB = 0.2 x HGSB0.45 x MRS
0.45
= 0.2 x 300 x 50= 130.22 MPa
= 130.22 x *145.038 PSI = 18888.01 PSI
(*Note: MPa to PSI Conversion factor: I MPa =
145.038 PSI)
Resilient Modulus of Granular Base (in PSI)
MRGB = 0.2 x HGB.45 x MRSUPPORT
Here, MRSUPPORT = effective MR of GSB and
subgrade (Section 8.1 of IRC 37: 2018)
Effective MR of GSB and subgrade has been
determined by the procedure given in Annex II.I of
IRC 37:2018. The MR of GSB and effective Subgrade
are entered into IIT Pave with 2 layered system, with
single wheel load of 40000 N, tyre pressure of 0.56
MPa and the displacement at the top of GSB is
determined using IITPave software as shown below.
Fig. IV-2 Screenshot of IIT Pave for Deflection
induced in pavement layers
From the above output of IIT Pave software, the
displacement works out as 1.631 mm and
corresponding MR value is determined as per
Equation 6.3 of IRC 37:2018
Based on MRSUPPORT, the value of MR of Base is
determined as shown below.
Resilient Modulus of Bituminous Layers BC+DBM (in MPa)
MRM = 3000 MPa
50
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
8
Example 1
(Page No.
86 & 87)
Layer coefficient for bituminous layer (a1) =
0.436
(c) Structural Layer coefficient for base
layer shall be taken from b equations
given in AASHTO 1993.
Structural layer coefficient for base layer
a2 = 0.249× (log10MR_GB) – 0.977 = 0.249 ×
(log10 32632.65)-0.977 =0.147
Calculation of structural layer coefficients for
Base and Sub base Layers
(a) Structural layer coefficient for Granular
Base / WMM Layer (a2)
Modified Layer coefficient for sub base
layer (a3) = 0.120
Considering the LCR value of 1.4#1 (the value of
1.4 is the average value of LCR as per Table 3.1
of IRC:SP:59-2019), the subsequent calculations
for determining improved resilient modulus and
pavement thickness are provided below.
a2 = 0.249 x (log10MRGB) – 0.977
= 0.249x (log10 28601.96) – 0.977
= 0.1326
(b) Structural Layer coefficient for Granular
Sub base Layer (a3)
(d) Structural layer coefficient for subbase
layer
a3 = 0.227 x (log10MRGSB) – 0.839
a3 = 0.227(log10MR_GSB) – 0.839 = 0.227 × = 0.227 x (log10 18888.01) - 0.839
(log1016678.91)-0.839 = 0.120
= 0.1317
Therefore,
The Geogrid in Granular Base (WMM) layer will
Modified Layer coefficient for base layer (a2) enhance the modulus value of Base which is
= 0.147
obtained by multiplying it by LCR value.
1
# LCR value shown is strictly indicative and
manufacturer-specific LCR values with accredited
certificate shall be adopted for actual designs.
9
Example 1
Modified layer coefficient for a base layer Calculations of Improved structural layer
coefficients
(Page No. 87) (a2') = LCRbase × a2
= 1.4*0.147= 0.2058
Improved layer coefficient for base layer
1
Modified layer coefficient for sub-base layer
(a2 ) = LCRBase × a2
(a3') = LCRSubbase × a3
= 1.40*0.1326 = 0.1856
= 1.61*0.120= 0.1932
Improved layer coefficient for sub-base layer
(a31) = LCRGSB × a3
= 1*0.1317= 0.1317
10
Example 1
With the improved layer coefficients, With the improved layer coefficients, improved
(Page No. 87) improved elastic modulus of respective resilient modulus of respective layers shall be
layers shall be back-calculated using below back-calculated using below equations.
equations.
a21 = 0.249× (log10MR_GB) – 0.977
MR_GB1 = 393 MPa
a31 = 0.227(log10MR_GSB) – 0.839
MR_GSB1= 244MPa
Using the above improved elastic modulus
corresponding improved layer coefficients,
r e i n f o r c e d l a y e r t h i c k n e s s s h a l l b e Using the above Improved Resilient Modulus,
determined.
reinforced layer thickness shall be determined.
INDIAN HIGHWAYS
SEPTEMBER 2022
51
NOTIFICATION
S.
No.
Clause No.
Page No.
11
Example 1
(Page No. 87)
For
Read
Analysis of Geogrid Reinforced Flexible
Pavement Section By entering the above thicknesses and MR values
of reinforced pavement layers (BC+DBM,
Reinforced Base, GSB, Effective Subgrade) for a
wheel load of 20000 N, a tyre pressure of 0.56
MPa and dual wheelset in IITPave software, the
induced tensile and vertical strains are
determined below the DBM and over the
subgrade layer respectively as per the procedure
given in IRC 37:2018.
Fig. IV-3 Input parameters in IITPave
software for reinforced section
Fig. IV-4 Screen shot of IIT Pave for Horizontal
tensile strains and vertical compressive strains
induced in pavement layers for reinforced section
From the above output of IIT Pave, it is observed that
the induced strains are less than the permissible
strains as shown below.
The induced maximum horizontal tensile strain
149.0 x 10-6 < 151.7 x 10-6
The induced maximum vertical compressive
strains = 291.1 x 10-6 < 319.0 x 10-6
The above calculations indicate that the adopted
pavement design is safe from rutting and fatigue
strain criteria. Fig. IV-5 shows the typical crosssection of conventional and Geogrid reinforced
flexible pavement.
52
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION
S.
No.
12
Clause No.
Page No.
For
Read
Example 1
Reinforced base layer thickness = 160 mm
(Page No. 87) Reinforced subbase layer thickness = 180 mm
Surface layer (BC+DBM) = 150 mm
Fig. IV-5 Typical Cross Section of Conventional
&
Geogrid Reinforced Flexible Pavement
Fig. IV-1 Pavement Sections with and
without reinforcement
The pavement with Geogrid reinforcement can
also be designed with MIF method as illustrated
in the example for Geocell
13
Example 1
This reinforced pavement section shall be
(Page No. 88 designed as per IRC: 37 i.e. section shall be
checked for fatigue and rutting failure
& 89)
criterion by inputting this improved elastic
modulus into IITPAVE. Fig. IV-4, shows the
input parameters in IITPAVE, in which
improved E values are used. Fig. IV-5
represents the vertical and tensile strains
induced in the pavement layers. Obtained
-6
vertical strain at subgrade level is 360.4×10
which is less than the permissible vertical
strain 372×10-6 obtained as per Eq 6.5 in
IRC:37 and obtained tensile strain at bottom
of bitumen layer is 146.7×10-6 is less than
permissible 155×10-6 tensile strain obtained
as per Eq 6.2 of IRC:37. Hence the reduced
section with geogrid reinforcement in base
and subbase layers is acceptable for design
traffic 50 msa.
Deleted
Fig. IV-2 Input Parameters in IITPAVE
for Unreinforced Section
INDIAN HIGHWAYS
SEPTEMBER 2022
53
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
Fig. IV-3 Vertical and Tensile Strains
Induced in the Pavement Layers
for Unreinforced Section
Fig. IV-4 Input Parameters in IITPAVE for
Reinforced Section
Fig. IV-5 Vertical and Tensile Strains
Induced in the Pavement Layers for
Reinforced Section
14
Example 2
Example 2: Design Example for Flexible Section C- Design Example using Geocells as
Pavement
using Geocells
Reinforcement in Flexible Pavement using
P(age No. 89)
Modified Improvement Factor (MIF) Method
15
Example 2
Consider a pavement to be constructed on
(Page No. 89) marine clay with a CBR of 2%. The design
life of the structure, reflected as million
standard axles (MSA), as 100 msa.
Deleted
16
Example 2
As a matter of good practice and as per IRC:
37 Clause 5.1, it would be prudent to provide
Solution:
(Page No. 89) a 500 mm thick layer of select earth over the
dressed clay surface. With the soft marine
Deleted
54
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
clay below, the CBR of the earth fill may not
be considered greater than 3%, which is also
the lowest CBR considered by IRC: 37. On
the basis of the Plate shown in Fig. IV-6, the
section of the conventional pavement for
100 msa traffic is as per Fig. IV-7.
Fig IV-6 Plate 1 from IRC:37
In Fig. IV-7, it may be noted that nonwoven
geotextile is provided at the interface
between the marine clay and the select earth
fill as a separation layer.
Fig IV-7 Conventional Pavement Section
as per IRC:37
Considering Design Traffic as 100 msa and
for 90% reliability,
INDIAN HIGHWAYS
SEPTEMBER 2022
55
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
Hence for the recommended conventional
pavement section, permissible vertical
subgrade strain and horizontal tensile strain
are 319.0 x 10 - 6 and 129.94 x 10 - 6
respectively.
These values will form the basis of checking
the reduced thicknesses of pavement
components with the introduction of
geocells within the appropriate pavement
layer. For the reduced section with geocells,
the strains should be equal to or less than
those for the conventional section at the
corresponding locations. These criteria must
be satisfied for the various options using
geocells as discussed below.
17
Example 2
(Page No. 91)
New Section Added
By iteration, the following thicknesses are
arrived at by using IITPave software (IRC-372018)
Bituminous Concrete (BC) = 50 mm
Dense Bituminous Macadam (DBM) = 110 mm
Granular Base (WMM) = 200 mm
Granular Sub-Base (GSB) = 300 mm
Determination of Resilient Modulus as per
IRC 37: 2018
For reinforced pavement design with Geocell
using MIF method, the Base and GSB layers are
considered separately for calculation of MR
values as per Section 8.1 of IRC 37:2018, unlike
conventional method where both GSB and Base
are considered together.
Resilient Modulus of subgrade (in MPa)
MRS = 10 x CBR (For CBR< 5% )
(Equation 6.1 of IRC 37: 2018)
MRS = 10 x 5 = 50 MPa
56
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
Resilient Modulus of Granular Sub-Base (in
MPa)
MRGSB = 0.2 x HGSB0.45 x MRS
= 0.2 x 3000.45 x 50= 130.22 MPa
Resilient Modulus of Granular Base (in MPa)
MRGB = 0.2 x HGB0.45 x MRSUPPORT
Here, MRSUPPORT = effective MR of GSB and
subgrade (Section 8.1 of IRC 37: 2018)
Effective MR of GSB and subgrade is determined
as per Annex II.I of IRC 37:2018. The MR of GSB
and effective Subgrade are entered into IIT Pave
with 2 layered system, with a single wheel load of
40000 N, tyre pressure of 0.56MPa and the
displacement at the top of GSB is determined
using IITPave software as shown below.
Fig. IV-6 Screenshot of Deflection Induced in
Pavement Layers
From the above output of IIT Pave, the
displacement works out as 1.631 mm and
corresponding MR value is determined as per
Equation 6.3 of IRC:37-2018
MRGB = 0.2 x 2000.45 x 90.87
= 197.203 MPa
Resilient Modulus of Bituminous Layers BC+DBM (in MPa)
MRM = 3000 MPa
The use of Geocell in Base-layer will enhance the
modulus value of Base which is obtained by
multiplying it by MIF value. Considering the MIF
value of 1.7#2 (the value of 1.7 is the average value
of MIF as per Table 3.2 of IRC:SP:59), the
subsequent calculations for determining
Improved Resilient Modulus and pavement
thickness are given below.
The MR of reinforced Base layer, MRGB = MRGB x
MIF
INDIAN HIGHWAYS
SEPTEMBER 2022
57
NOTIFICATION
S.
No.
Clause No.
Page No.
For
Read
Improved MRGB = 197.203 x 1.7
= 335.245 MPa
Using the above Improved Resilient Modulus,
reinforced layer thickness shall be determined.
2
# MIF value shown is strictly indicative and
manufacturer-specific MIF values with proper
accredited certificate shall only be adopted for actual
designs.
18
Example 2
The Geocell Options:
(Page No. 91) The geocell panels are placed within either
Granular Base layer or Granular Sub-base layer.
Modulus of the portion of the layer within
which the geocells are placed is increased by a
Modulus Improvement Factor. With the geocell
layer in place, the thickness of the costliest layer
may be first selected for reduction.
Computations are repeated with IITPAVE
with the appropriate moduli values. Varying
the thicknesses by trial and error, two sections
were arrived at as shown in Fig. IV-8. These
were compared separately with the
conventional section.
Fig IV-8 Design Sections using Geocells
Note:
1. In all cases, Semi-Dense Bituminous
Concrete (SDBC) thickness has been
retained as 50 mm.
2. If DBM is maintained at 50 mm, the strains
exceed those for Conventional Section.
Option 1
Material properties for the geocell section are
shown in Fig. IV-9 are as following:
i. CBR of Subgrade soil = 3%
ii. Traffic = 100 msa.
iii. Geocell Style = Weld spacing = 356 mm;
Depth of geocell = 150 mm
58
INDIAN HIGHWAYS
SEPTEMBER 2022
Deleted
NOTIFICATION
S.
No.
Clause No.
Page No.
19
Example 2
(Page No. 92)
For
Read
Analysis of Geocell Reinforced Pavement
Section- By entering the above thicknesses and MR
values of reinforced pavement layers (BC+DBM,
Reinforced Base, GSB, Effective Subgrade) for a
wheel load of 20000 N (refer para 7.2.2, vi, p 22
IRC 37-2018), a tyre pressure of 0.56 MPa and dual
wheelset in IITPave software, the induced tensile
and vertical strains are determined below the DBM
and over the subgrade layer respectively as per the
procedure given in IRC 37: 2018.
Fig IV-9 Material Properties for the
Analysis of the Geocell Section
Fig. IV-7 Input Parameters in IITPave Software
for Reinforced Section
20
Example 2
Results of the corresponding stress-strain
(Page No. 92) analysis are shown in Fig. IV-10.
Fig. IV-8 Screenshot of IIT Pave for
Horizontal Tensile Strains and Vertical
Compressive Strains induced in Pavement
Layers for Reinforced Section
Fig IV-10 Stress Strain Values from the
Analysis
21
Example 2
Vertical strain at the interface with the
-6
(Page No. 93) subgrade is 309.1 x 10 micro-strain units.
The corresponding strain for the
Conventional Section is 100.7 x 10-6 microstrain units. Hence the thinner section with
geocells is acceptable. Furthermore,
considering the rutting model the as per
IRC:37, the number of standard axles over the
pavement with the new moduli with geocells
works out to 115 msa with 90% reliability.
From the above output of IIT Pave, it is observed
that the induced strains are less than the
permissible strains as shown below.
The induced maximum horizontal tensile strain
150.3 x 10-6 < 151.7 x 10-6
The induced maximum vertical compressive
strain =296.1 x 10-6 < 319.0 x 10-6
INDIAN HIGHWAYS
SEPTEMBER 2022
59
NOTIFICATION
S.
No.
Clause No.
Page No.
22
Example 2
(Page No. 93)
For
Read
Fig. Added
Hence the adopted pavement design is safe from
rutting and fatigue strain criteria. Fig. IV-9 shows
the typical cross-section of conventional and
Geocell reinforced flexible pavement.
Fig. IV-9 Typical Cross Section of Conventional
& Geocell Reinforced Flexible Pavement
23
Example 2
(Page No. 93)
Notes Added
Note:
1. The pavement with Geogrid reinforcement can
also be designed with MIF method as
illustrated in the example for Geocell. Higher
pavement thicknesses arrived from the design
with LCR and MIF methods shall be adopted
in the field.
2. The examples given above are only for
illustration of design methodology. In the
above two design methods. the geosynthetic
(geogrid/geocell) reinforced pavements have
been designed for the same parameters by
optimising the thickness of the base layer and
DBM layer. Designer can adopt other options
such as placing Geosynthetics (Geogrid/
Geocell) in the GSB layer and altering the
thicknesses of the base and the bituminous
layers to optimise the design.
3. LCR and MIF values shown are strictly
indicative values and manufacturer-specific
MIF/LCR values with proper accredited
certificate shall be adopted for actual designs
of reinforced pavements.
4. The manufacturer shall supply construction
methodology and specifications with the
Geogrid/Geocell as per the requirements of
pavement design and site conditions.
60
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION
NOTIFICATION NO. 49
st
Amendment No.2/IRC:112-2020/June, 2022 (Effective from 1 September, 2022)
To
IRC:112-2020 Code of Practice for Concrete Road Bridges (First Revision)
Sr
No.
Clause No.
Page No.
Read
1
15.3.1.1 (2)
(Page No. 136)
2
18.3.2
The following grades of steel having T h e f o l l o w i n g g r a d e s o f s t e e l h a v i n g
characteristics
as mentioned in Table 18.3 to characteristics as mentioned in Table 18.3 to 18.5,
(Page No. 171)
18.5, are permitted for use in bridges designed are permitted for use in bridges.
for normal life.
For
- Addition of 5th bullet point
Individual cables from bundled cables shall be
deviated or draped to separate towards
anchoring locations. Cables shall be profiled in
this zone in a manner such that curved cable shall
not cause any adverse force on duct of other
cable in the bundle when any cable from the
bundle is stressed. Only one cable from bundled
cables shall be deviated or draped at a time, such
that it moves away from other cable in the bundle.
The alignment of other cable shall continue to be
straight until clear distance / concrete thickness
between these two cable ducts is sufficient to
resist forces exerted due to curvature of the other
cable when stressed or equal to the duct diameter
or 50 mm, whichever is greater. The cables shall
remain in plane of bundled cables until this point.
For other bridges mentioned in clause 5.8.1
wires/strands having smaller diameters than
those given in the Tables, but otherwise
meeting the requirements of Indian standards
mentioned therein, can be used.
3
13.4.2
(Page No. 112)
Addition of new sub-clause (5)
Minimum internal cross sectional area of MS
Sheathing duct shall not be less than 3 times the
cross sectional area of the tendon which can be
fitted in the anchorage system used. However, in
case of threading of tendons after concreting for
spans larger than 30 m, internal diameter of the
duct shall be 5 mm larger than the requirement
stated above, in order to facilitate threading.
4
13.4.3 (4)
Minimum internal diameter of the HDPE duct
(Page No. 113) shall not be less than 3 times the cross sectional
area of the tendon which can be fitted in the
anchorage system used. However, in case of
threading of tendons after concreting for spans
larger than 30 m, internal diameter of the duct
shall be 5 mm larger than the requirement stated
above, in order to facilitate threading.
Minimum internal cross sectional area of the
HDPE duct shall not be less than 3 times the cross
sectional area of the tendon which can be fitted in
the anchorage system used. However, in case of
threading of tendons after concreting for spans
larger than 30 m, internal diameter of the duct
shall be 5 mm larger than the requirement stated
above, in order to facilitate threading.
5
17.2.2 (2)
Along straight section boundaries, restraining Along straight section boundaries, restraining of
(Page No. 164) of longitudinal bars should be achieved in longitudinal bars should be achieved in either one
of two ways mentioned in (a) & (b) below:
either one of following ways:
INDIAN HIGHWAYS
SEPTEMBER 2022
61
NOTIFICATION
NOTIFICATION NO. 50
Amendment No.2/IRC:78-2014/June, 2022 (Effective from 1st September, 2022)
To
IRC:78-2014 Standard Specifications and Code of Practice for Road Bridges
And
Amendment No.3/IRC:112-2020/June, 2022 (Effective from 1st September, 2022)
To
IRC:112-2020 Code of Practice for Concrete Road Bridges (First Revision)
Sr
No.
62
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
CLAUSE 707: OPEN FOUNDATION - CLAUSES OF IRC:78 TRANSFERRED TO IRC:112
New proposed Clause in IRC : 112
(With Clause No. & Text)
1
707.2.1
The thickness of the footings
(Page No.19) shall not be less than 300 mm.
Y
Y
16.15
Foundation
16.15.1
Open Foundation
16.15.1.1 The thickness of the footings
shall not be less than 300 mm.
2
707.2.2
Bending moments
(Page No.19)
Y
Y
16.15.1.2 Bending Moments
3
707.2.2.1
For solid wall type substructure
(Page No. 19) with one-way reinforced footing,
the bending moments can be
determined as one-way slab for
the unit width subjected to worst
combination of loads and forces.
Y
Y
a) For solid wall type substructure with
one-way reinforced footing, the
bending moments can be determined
as one-way slab for the unit width
subjected to worst combination of
loads and forces.
4
707.2.2.2
(Page No. 19
to 20)
For two-way footing, bending
moment at any section of the
footing shall be determined by
passing a vertical plane through
the footing and computing the
moment of the forces acting over
the entire area of footings one
side of the vertical plane. The
critical section of bending shall
be at the face of the solid column.
Y
Y
b) For two-way footing, bending
moment at any section of the footing
shall be determined by passing a
vertical plane through the footing and
computing the moment of the forces
acting over the entire area of footings
one side of the vertical plane. The
critical section of bending shall be at
the face of the solid column.
5
707.2.2.3
In case of circular footings or
(Page No. 20) polygonal footings, the bending
moments in the footing may be
determined in accordance with
any rational method. Methods
given by Timoshenko and Rowe
for Plate Analysis are acceptable.
Y
Y
c) In case of circular footings or polygonal
footings, the bending moments in the
footing may be determined in
accordance with any rational method.
Methods given by Timoshenko and
Rowe for Plate Analysis are acceptable.
6
707.2.2.4
For combined footings supporting
(Page No. 20) two or more columns, the critical
sections for bending moments
along the axis of the columns shall
be at the face of the columns/ walls.
Y
Y
d) For combined footings supporting
two or more columns, the critical
sections for bending moments along
the axis of the columns shall be at the
face of the columns/ walls. Further, for
INDIAN HIGHWAYS
SEPTEMBER 2022
Sr
No.
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
New proposed Clause in IRC : 112
(With Clause No. & Text)
Further, for determination of
critical sections for bending
moments between the column/
walls, any rational method of
analysis be adopted.
Y
Y
determination of critical sections for
bending moments between the
column/walls, any rational method of
analysis be adopted.
7
707.2.3
The shear strength of the footing
(Page No. 20) may be checked at the critical
section which is the vertical
section at a distance 'd' from the
face of the wall for one-way
action where 'd' is the effective
depth of the section at the face of
the wall.
Y
N
Relevant provisions already exist in
IRC:112
8
707.2.3.1
For two-way action for slab or
(Page No. 20) footing, the critical section should
be perpendicular to plan of slab
and so located that its perimeter is
minimum, but need not approach
closer than half the effective
depth from the perimeter of
concentrated load or reaction
area.
Y
N
Relevant provisions already exist in
IRC:112
9
707.2.4
To ensure proper load transfer, a
(Page No. 20) limiting value of ratio of depth to
length/width of footing equal to
1:3 is specified. Based on this, for
sloped footings the depth
effective at the critical section
shall be the minimum depth at the
rd
end plus 1/3 of the distance
between the extreme edge of the
footing to the critical section for
design of the footing for all
purposes.
Y
Y
16.15.1.2 To ensure proper load transfer, a
limiting value of ratio of depth to
length/width of footing equal to 1:3 is
specified. Based on this, for sloped
footings the depth effective at the critical
section shall be the minimum depth at the
end plus 1/3rd of the distance between the
extreme edge of the footing to the critical
section for design of the footing for all
purposes.
10
707.2.5
The critical section for checking
(Page No. 20) d e v e l o p m e n t l e n g t h o f
reinforcement bars should be
taken to be the same section as
given in Clause 707.2.3 and also
all other vertical planes where
abrupt changes in section occur.
Y
N
Relevant provisions already exist in
IRC:112
11
707.2.6
Tensile reinforcement
(Page No. 20)
Y
Y
16.15.1.3
INDIAN HIGHWAYS
Reinforcement Detailing in
Open Foundation
SEPTEMBER 2022
63
Sr
No.
64
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
New proposed Clause in IRC : 112
(With Clause No. & Text)
707.2.6.1
The tensile reinforcement shall
(Page No. 20) provide a moment of resistance at
least equal to the bending
moment on the section calculated
in accordance with Clause
707.2.2.
16.15.1.3.1 General
707.2.6.2
The tensile reinforcement shall
(Page No. 20) b e d i s t r i b u t e d a c r o s s t h e
corresponding resisting section
as below:
b) In case of circular footings, the main
reinforcement may be placed
orthogonally and concentrated in the
middle half of the footing, for a width
of 50% ± 10% of the diameter of the
footing. The unreinforced parts of the
element should be considered as plain
concrete for design purposes.
a)
In one-way reinforced
footing, the reinforcement
shall be same as calculated
for critical unit width as
mentioned in Clause
707.2.2.1.
b)
In two-way reinforced square
footing, the reinforcement
extending in each direction
shall be distributed
uniformly across the full
section of the footing.
c)
In two-way reinforced
rectangular footing, the
reinforcement in the long
direction shall be distributed
uniformly across the full
width of the footing. For
reinforcement in the short
direction, a central band equal
to the short side of the footing
shall be marked along the
length of the footing and
portion of the reinforcement
determined in accordance
with the equation given
below shall be uniformly
distributed across the central
band:
INDIAN HIGHWAYS
SEPTEMBER 2022
a) The main reinforcement should be
anchored in accordance with the
requirements of clause 15.2.4. A
minimum bar diameter of 10mm
should be provided.
0.5 B
B
Figure 16.12: Orthogonal reinforcement
in circular spread footing on soil
c) If the load effects under any load
combination cause tension at the
upper surface of the footing, the
resulting tensile stresses should be
checked and reinforced as necessary.
16.15.1.3.2 Anchorage of bars
a) The tensile force in the reinforcement
is determined from equilibrium
conditions, taking into account the
Sr
No.
Clause No.
Page No.
Clause As written
in IRC:78
Where β = the ratio of the long
side to the short side of the
footing
The remainder of the reinforcement
shall be uniformly distributed in the
outer portions of the footing.
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
New proposed Clause in IRC : 112
(With Clause No. & Text)
effect of inclined cracks, see Figure
16.13. The tensile force Fs at a location
x should be anchored in the concrete
within the same distance x from the
edge of the footing.
Figure 16.13: Model for tensile force
with regard to inclined cracks
b) The tensile force to be anchored is
given by:
Fs = R. Ze /Z1
Where:
R is the resultant of ground pressure
within distance x Ze is the external
lever arm, i.e. distance between R and
the vertical force Ned
Ned is the verticalforce corresponding
to total ground pressure between
sections A and B Z1 is the internal lever
arm, i.e. distance between the
reinforcement and the horizontal force
FC
FC is the compressive force
corresponding to maximum tensile
force Fs.max
c) Lever arms Z e and Z 1 may be
determined with regard to the
necessary compression zones for Ned
and FC respectively. As simplification,
Ze may be determined assuming e =
0.15 b, see Figure 16.13 and Z1 may
be taken as 0.9 d.
INDIAN HIGHWAYS
SEPTEMBER 2022
65
Sr
No.
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
New proposed Clause in IRC : 112
(With Clause No. & Text)
d) The available anchorage length for
straight bars is denoted lb in Figure
16.13. If this length is not sufficient to
anchor Fs, bars may either be bent up
to increase the available length or be
provided with end anchorage devices.
e) For straight bars without end
anchorage the minimum value of x is
the most critical. As a simplification
Xmin = h/2 may be assumed. For other
types of anchorage, higher values of x
may be more critical.
16.15.1.4 Column Footing on Rock
(a) Adequate transverse reinforcement
should be provided to resist the
splitting forces in the footing, when the
ground pressure in the ultimate states
exceeds 5 Mpa. This reinforcement
may be distributed uniformly in the
direction of the splitting force over the
height h (see Fig 16.14). A minimum
bar diameter, 12mm, should be
provided.
(b) The splitting force, F s , may be
calculated as follows (see Figure
16.14):
Fs = 0,25 (1 – c / h) NEd
Where h is the lesser of b and H
Figure 16.14: Splitting reinforcement
in Footing or Rock
66
INDIAN HIGHWAYS
SEPTEMBER 2022
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
Sr
No.
Clause No.
Page No.
Clause As written
in IRC:78
New proposed Clause in IRC : 112
(With Clause No. & Text)
12
707.2.7
(Page No. 21)
The area of tension reinforcement
should as per IRC: 112, Clause
number 16.5.1.1.
Y
N
Relevant provisions already exist in
IRC:112
13
707.2.8
(Page No. 21)
All faces of the footing shall be
provided with a minimum steel of
250 mm2/meter in each direction
for all grades of reinforcement.
Spacing of these bars shall not be
more than 300 mm. This steel
may be considered to be acting as
tensile reinforcement on that
face, if required from the design
considerations.
Y
N
Relevant provisions already exist in
IRC:112
Sr
No.
Clause No.
Page No.
709.4
14
15
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
CLAUSE 709 : PILE FOUNDATION CLAUSES OF IRC : 78 TRANSFERRED TO IRC:112
New or Existing Clause in
IRC : 112
with Clause No or Text of New
Clause & No.
Structural Design of Piles
709.4.1
A pile as a structural member shall
(Page No. 40) have sufficient strength to transmit
the load from structure to soil. The
pile shall also be designed to
withstand temporary stresses, if
any, to which it may be subjected
to, such as, handling and driving
stresses. The permissible stresses
should be as per IRC:112. The test
pile shall be separately designed to
carry test load safely to the
foundation.
Y
709.4.2
The piles may be designed taking
(Page No. 40) into consideration all the load
effects and their structural
capacity examined as a column.
The self-load of pile or lateral
load due to earthquake, water
Y
Y
16.15.2 New Clause PILE FOUNDATIONS
in IRC:112
16.15.2 .1
A pile as a structural member shall have
sufficient strength to transmit the load
from structure to soil. The pile shall also be
designed to withstand temporary loadings,
if any, to which it may be subjected to,
such as, handling and driving forces.
The test pile shall be separately designed
to carry test load safely to the foundation.
Y
16.15.2.2 New Clause in IRC:112
The piles may be designed taking into
consideration all the load effects and their
structural capacity examined as a column.
The self-load of pile or lateral load due to
earthquake, water current force, etc.
INDIAN HIGHWAYS
SEPTEMBER 2022
67
Sr
No.
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
water current force, etc. on the
portion of free pile up to scour
level and up to potential
liquefaction level, if applicable,
should be duly accounted for.
16
17
68
on the portion of free pile up to scour level
and up to potential liquefaction level, if
applicable, should be duly accounted for.
709.4.3
For the horizontal loads the
(Page No. 40) moments in pile shaft can be
calculated as described in Clause
709.3.5.2. For piles on land, if the
pile group is provided with rigid
cap, then the piles may be
considered as having fixed head
in appropriate direction for this
purpose. Horizontal force may be
distributed equally in all piles in a
group with a rigid pile cap.
Y
709.4.4
Reinforcements for cast-in-situ
(Page No. 40) piles
Y
The reinforcements in pile
should be provided complying
with the requirements of
IRC:112, as per the design
requirements. The area of
longitudinal reinforcement shall
not be less than 0.4 percent nor
greater than 2.5 percent of the
actual area of cross-section in all
cast-in-situ concrete piles. The
clear spacing between vertical
bars shall not be less than 100
mm. Grouping of not more than
two bars together can be made
for achieving the same. Lateral
reinforcement shall be provided
in the form of spirals with
minimum 8 mm diameter steel,
spacing not more than 150 mm.
For inner layer of reinforcement,
separate links tying them to each
other and to outer layers shall be
provided.
INDIAN HIGHWAYS
SEPTEMBER 2022
New or Existing Clause in
IRC : 112
with Clause No or Text of New
Clause & No.
Y
16.15.2.3 New Clause in IRC:112
For the horizontal loads, the moments in
pile shaft can be calculated by appropriate
rational method of analysis using soil
modulus as recommended in IRC:78, Part
2. For piles on land, if the pile group is
provided with rigid cap, then the piles
may be considered as having fixed head in
appropriate direction for this purpose.
Horizontal forces coming from top at the
bottom of pile cap may be distributed
equally in all piles in a group with a rigid
pile cap.
Y
New Clause 16.15.2.4 in IRC:112
The reinforcements in pile should be
provided complying with the requirements
of this code, as per the design requirements.
The area of longitudinal reinforcement shall
not be less than 0.4 percent nor greater than
2.5 percent of the actual area of crosssection in all cast-in-situ concrete piles. The
clear spacing between vertical bars shall not
be less than 100 mm. Grouping of not more
than two bars together can be made for
achieving the same. Lateral reinforcement
shall be provided in the form of spirals with
minimum 8 mm diameter steel, spacing not
more than 150 mm. For inner layer of
reinforcement, separate links tying them to
each other and to outer layers shall be
provided.
Sr
No.
18
Clause No.
Page No.
Clause As written
in IRC:78
709.4.5
For pre-cast driven piles, the
(Page No. 40) reinforcement should comply
with the provision of IRC:112,
for resisting stresses due to
lifting, stacking and transport,
any uplift or bending transmitted
from the superstructure and
bending due to any secondary
effects. The area of longitudinal
reinforcement shall not be less
than the following percentages of
the cross-sectional area of the
piles:
a)
For piles with a length less
than 30 times the least width 1.25 percent;
b)
For piles with a length 30 to 40
times the least width - 1.5
percent; and
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
Y
Y
New or Existing Clause in
IRC : 112
with Clause No or Text of New
Clause & No.
16.15.2.5 New Clause in IRC:112
For pre-cast driven piles, the reinforcement
should be provided for resisting forces due to
lifting, stacking , transporting, driving and
any uplift or bending transmitted from the
superstructure and bending due to any
secondary effects. The area of longitudinal
reinforcement shall not be less than the
following percentages of the cross-sectional
area of the piles:
a) For piles with a length less than 30
times the least width - 1.25 percent;
b) For piles with a length 30 to 40 times
the least width - 1.5 percent; and
c) For piles with a length greater than 40
times the least width - 2 percent.
c) For piles with a length greater
than 40 times the least width - 2
percent.
709.5
19
Design of Pile Cap
709.5.4
The minimum thickness of pile
(Page No. 41) cap should be 1.5 times the
diameter of pile. Such a pile cap
can be considered as rigid. The
pile cap may be designed as thick
slab or, by using 'strut & tie'
method. All reinforcement in pile
cap shall have full anchorage
capacity beyond the point at
which it is no longer required. It
should be specially ascertained
for pile cap designed by 'strut &
tie' method. Where large
diameter bars are used as main
reinforcement, the corners of pile
caps have large local cover due to
large radius of bending of main
bars. Such corners shall be
protected by locally placing
small diameter bars.
Y
Y
16.15.2.6 New Clause in IRC:112
Design of pile cap
The minimum thickness of pile cap should
be 1.5 times the diameter of pile. All
reinforcement in pile cap shall have full
anchorage capacity beyond the point at
which it is no longer required. It should be
specially ascertained for pile cap designed
by 'strut & tie' method. Where large
diameter bars are used as main
reinforcement, the corners of pile caps
have large local cover due to large radius
of bending of main bars. Such corners
shall be protected by locally placing small
diameter bars.
INDIAN HIGHWAYS
SEPTEMBER 2022
69
NOTIFICATION
Sr
No.
20
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
CLAUSE 710: PIER & ABUTMENT - CLAUSES OF IRC:78 TRANSFERRED TO IRC : 112
710.2.10
The lateral reinforcement of the
(Page No. 46) walls of hollow circular RCC pier
shall not be less than 0.3 percent of
the sectional area of the walls of
the pier. This lateral reinforcement
shall be distributed 60 percent on
outer face and 40 percent on inner
face.
Y
21
710.3.1
When the length of solid pier is
(Page No. 46) m o r e t h a n f o u r t i m e s i t s
thickness, it shall also be checked
as a wall.
Y
N
Relevant provisions already exist in
IRC:112
22
710.3.2
The reinforced wall should have
(Page No. 46) minimum vertical reinforcement
equal to 0.3 percent of sectional
area.
Y
N
Relevant provisions already exist in
IRC:112
23
710.3.3
For eccentric axial load, the wall
(Page No. 46) should be designed for axial load
with moment. The moments and
the horizontal forces should be
distributed taking into account
the dispersal by any rational
method.
Y
N
Relevant provisions already exist in
IRC:112
24
710.3.4
The vertical reinforcement need not
(Page No. 46) be enclosed by closed stirrups,
where vertical reinforcement is not
required for compression.
However, horizontal reinforcement
should not be less than 0.25 percent
of the gross area and open links (or
S-Ioops) with hook placed around
the vertical bar should be placed at
the rate of 4 links in one running
meter.
Y
N
Relevant provisions already exist in
IRC:112
25
710.3.5
When walls are fixed with
(Page No. 46) superstructure, the design moment
and axial load should be worked out
by elastic analysis of the whole
structure.
Y
N
Relevant provisions already exist in
IRC:112
70
INDIAN HIGHWAYS
SEPTEMBER 2022
Y
New or Existing Clause in
IRC : 112
with Clause No or Text of New
Clause & No.
New Clause Addition at Serial No. 3 of
16.4.1
(3) The lateral reinforcement of the walls
of hollow circular RCC pier shall not be
less than 0.3 percent of the sectional area
of the walls of the pier. This lateral
reinforcement shall be distributed 60
percent on outer face and 40 percent on
inner face.
Sr
No.
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
New or Existing Clause in
IRC : 112
with Clause No or Text of New
Clause & No.
26
710.8.4
In case of bearings are placed
(Page No. 50) centrally over the column and
width of bearings/ pedestals is
located within half the depth of
cap from any external face of the
columns, the load from bearings
will be considered to have been
directly transferred to column and
cap beam need not to be designed
for flexure.
Y
N
Relevant provisions already exist in
IRC:112
27
710.8.7
Reinforcement in Pier and
(Page No. 50) Abutment Caps where the
bearing satisfied the square-root
formula stated in Clause 307.1 of
IRC:21, the pier caps shall be
reinforced with a total minimum
of 1 percent steel, assuming a cap
thickness of 225 mm. The total
steel shall be distributed equally
and provided both at top and
bottom in two directions. The
reinforcement in the direction of
the length of the pier shall extend
from end to end of the pier cap
while the reinforcement at right
angles shall extend for the full
width of the piers cap and be in
the form of stirrups. In addition,
two layers of mesh reinforcement
one at 20 mm from top and the
other at 100 mm from top of
pedestal or pier cap each
consisting of 8 mm bars at 100
mm centers in both directions
shall be provided directly under
the bearings.
Y
N
Relevant provisions already exist in
IRC:112
28
710.9.1
When the distance between the
(Page No. 51) load/centre line of bearing from
the face of the support is equal to
or less than the depth of the cap
(measured at the support) the cap
shall be designed as a corbel.
Y
N
Relevant provisions already exist in
IRC:112
29
710.9.2
The equivalent square area may
(Page No. 51) be worked out for circular pier to
determine the face of support for
calculating bending moments
Y
Y
New Clause added 16.7.1 Serial No (8)
ac shall be measured from the face of the
square of equal area of circular support.
INDIAN HIGHWAYS
SEPTEMBER 2022
71
Sr
No.
30
Clause No.
Page No.
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
Clause As written
in IRC:78
710.9.3
In case of wall pier and the pier
(Page No. 51) cap cantilevering out all around,
the measurement of distance for
purpose of the design as bracket
and the direction of provision of
reinforcement should be parallel
to the line joining the center of
load/bearing with the nearest
supporting face of Pier.
Y
31
710.9.4
Where a part of the bearing lies
(Page No. 51) directly over the pier, calculation
of such reinforcement should be
restricted only for the portion
which is outside the face of the
pier. Moreover, in such cases the
area of closed horizontal stirrups
may be limited to 25 percent of the
area of primary reinforcement.
Y
N
Relevant provisions already exist in
IRC:112
32
710.10.3
(Page No. 51
& 52)
Y
N
Relevant provisions already exist in
IRC:112
The allowable bearing pressure
with near uniform distribution on
the loaded area of a footing or
base under a bearing or column
shall be given by the following
equation
A
C = Co x A21
Co
where
C O = the permissible direct
compressive stress in concrete at
the bearing area of the base
A1= dispersed concentric area
which is geometrically similar to
the loaded area A2 and also the
largest area that can be contained
in the plane of A1 (maximum
width of dispersion beyond the
loaded area face shall be limited
to twice the height)
A2= loaded area and the projection
of the bases or footing beyond the
face of the bearing or column
supported on it shall not be less
than 150 mm in any direction
72
INDIAN HIGHWAYS
SEPTEMBER 2022
Y
New or Existing Clause in
IRC : 112
with Clause No or Text of New
Clause & No.
New Clause added at 16.3 Serial No. (3)
In case of wall pier and the pier cap
cantilevering out all around, the
measurement of distance for purpose of the
design as bracket and the direction of
provision of reinforcement should be parallel
to the line joining the center of load/bearing
with the nearest supporting face of Pier.
Sr
No.
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
New or Existing Clause in
IRC : 112
with Clause No or Text of New
Clause & No.
33
710.10.1
The pedestal should be
(Page No. 51) proportioned that a clear offset of
150 mm beyond the edges of
bearings is available
Y
N
Relevant provisions already exist in
IRC:112
34
710.10.4
The two layers of mesh
(Page No. 52) reinforcement-one at 20 mm
from top and the other at 100 mm
from top of pedestal or pier cap
each consisting of 8 mm bars at
100 mm in both directions, shall
be provided directly under the
bearings
Y
N
Relevant provisions already exist in
IRC:112
Sr
No.
35
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
CLAUSE 710.7: RETAINING WALL - CLAUSES OF IRC:78 TRANSFERRED TO IRC:112
Y
New proposed Clause in IRC : 112
(With Clause No. & Text)
710.7.1
The minimum thickness of
(Page No. 49) reinforced concrete retaining
wall shall be 200 mm.
Y
16.15.4 Retaining Wall:
36
710.7.2
The retaining walls shall be
(Page No. 49) designed to withstand earth pressure
including any live load surcharge
and other loads acting on it,
including self-weight, in accordance
with the general principles specified
for abutments. Stone masonry and
plain concrete walls shall be of solid
type. Reinforced concrete walls
may be of solid, counter fort,
buttressed or cellular type.
Y
N
Relevant provisions already exist in
IRC:112
37
710.7.3
The vertical stems of cantilever
(Page No. 49) walls shall be designed as
cantilevers fixed at the base. The
vertical or face walls of counterfort
Y
Y
16.15.4.2
The vertical stems of cantilever walls shall
be designed as cantilevers fixed at the base.
The vertical or face walls of counterfort
16.15.4.1 The minimum thickness of
reinforced concrete retaining wall shall
be 200 mm.
INDIAN HIGHWAYS
SEPTEMBER 2022
73
Sr
No.
Clause No.
Page No.
Clause As written
in IRC:78
Clause
deleted from IRC:78
(Yes / No)
Clause
inserted in IRC:112
(Yes / No)
NOTIFICATION
type and buttressed type shall be
designed as continuous slabs
supported by counterforts or
buttresses. The face walls shall be
securely anchored to the supporting
counterforts or buttresses by means
of adequate reinforcements.
38
74
710.7.4
Counterforts shall be designed as
(Page No. 49) T- beams or L-beams. Buttresses
shall be designed as rectangular
beams. In connection with the
main tension reinforcement of
counterforts, there shall be a
system of horizontal and vertical
bars or stirrups to anchor the face
walls and base slab to the
counterfort. These stirrups shall
be anchored as near to the outside
faces of the face walls and as near
to the bottom of the base slab as
practicable.
INDIAN HIGHWAYS
SEPTEMBER 2022
New proposed Clause in IRC : 112
(With Clause No. & Text)
type and buttressed type shall be designed
as continuous slabs supported by
counterforts or buttresses. The face walls
shall be securely anchored to the
supporting counterforts or buttresses by
means of adequate reinforcements.
Y
Y
16.15.4.3
Counterforts shall be designed as T- beams
or L-beams. Buttresses shall be designed as
rectangular beams. In connection with the
main tension reinforcement of counterforts,
there shall be a system of horizontal and
vertical bars or stirrups to anchor the face
walls and base slab to the counterfort. These
stirrups shall be anchored as near to the
outside faces of the face walls and as near to
the bottom of the base slab as practicable.
NOTIFICATION
NOTIFICATION NO. 51
Amendment No.7/IRC:6-2017/June, 2022 (Effective from 1st September, 2022)
To
IRC:6-2017 Standard Specifications and Code of Practice For Road Bridges,
Section-II Loads and Load Combinations” (Seventh Revision)
Sr
No.
Clause No.
Page No.
(Page No. 56)
Read
For
New Clause added 214.5 (Reproduce below)
New Clause 214.5
214.5 Combination of Seismic Inertia Forces on Soil/Wall Mass and Dynamic Active Earth Pressure on
Abutments and Retaining walls:
The following loads/actions (earthquake effects) shall be considered while designing abutments/retaining walls.
(i)
(ii)
(iii)
(iv)
Active Earth pressure including seismic effect (dynamic increment) due to backfill and Dead Load Surcharge, if
present in accordance with Clause 214.1.2 and 214.1.5. Live load surcharge shall not be considered in seismic
longitudinal case but shall be considered in seismic transverse cases.
Inertia forces acting on the mass of the abutment/retaining wall and the mass of the earth fill resting over its
foundation.
Longitudinal Inertia forces on superstructure transferred through fixed bearings or elastomeric bearings (when
elastomeric bearings are used to transmit seismic action) or connections (links/reaction blocks) and Transverse
Inertia forces on superstructure transferred through transversely fixed or elastomeric bearings or connections
(links/reaction blocks).
Hydraulic pressure i.e. any hydrostatic or hydrodynamic pressures, including buoyancy, if applicable when
drainage arrangements are not provided. The direction of the action of this force shall be in the direction of the
action of inertia force on substructure.
In absence of a rigorous analysis considering soil structure interaction for computing the combined effect of the
above-mentioned seismic actions, the following simplified method may be used.
Weight of soil mass resting on foundation (as stated in (ii) above) shall be considered in computation of horizontal
seismic force for the purpose of checking external stability i.e., for checking base pressure, overturning and
sliding and design of foundation.
The total longitudinal force (PSEIS) to be applied to the abutment/retaining wall due to dynamic earth pressure and
inertial forces on soil mass & wall, shall be determined considering the combined effect of (Paw)dyn, (Paq)dyn and
PIR in which
PSEIS = (Paw)dyn + (Paq)dyn + PIR
(with appropriate combinations as given below in 214.5.1 to 214.5.4)
(Paw)dyn= dynamic lateral earth pressure force (including static component as per Clause 214.1.2.1 and 214.1.5)
due to retained earth fill (as shown in Fig. 14C)
(Paq)dyn = dynamic lateral earth pressure force (including static component as per Clause 214.1.2.3 and 214.1.5)
due to permanent surcharge, if any (as shown in Fig. 14 C).
PIR = Ahs (WW+ WS)
PIR = horizontal inertial force due to seismic loading of the wall & soil mass resting on foundation
INDIAN HIGHWAYS
SEPTEMBER 2022
75
NOTIFICATION
214.5.1 Seismic Inertia Forces on Abutments/Retaining Walls
Following cases shall be considered for design:
(a)
Retaining Walls and Abutments on open foundation with Free sliding bearing –Seismic longitudinal case:
Ahs= horizontal seismic coefficient applied on weight of wall & soil mass, shall be taken = Z/2
The value of Ahs may be reduced to 50% x Z/2 = 0.25 Z for retaining walls/abutments when these have
displacement of 25 mm or more caused by dynamic lateral earth pressure including static component.
PIR = Ahs (WW+ WS)
WW = weight of abutment including wall and base slab WS = weight of soil resting on base slab
(b)
Abutments on Pile or Well foundations with Free sliding bearing-Seismic longitudinal case
The value of Ahs may be reduced to 50% x Z/2 = 0.25Z for abutments with deep foundation (pile or well) when
superstructure is supported on free sliding bearings and no inertia forces are transferred from superstructure.
Here
PIR = Ahs (Ww+ Ws)
Ww=weight of abutment including wall, pile and pile cap or well cap and well by considering variation of Ahs as per
Clause 4.7 of IRC:SP:114.
Ws = weight of soil resting on well or pile cap
(c)
Abutments on Open or Pile / Well foundations with Elastomer Bearings-Seismic longitudinal case:
Seismic coefficient Ah on mass of superstructure, abutment wall and well or pile cap when elastomeric bearings
are used to transmit seismic action, shall be calculated as per relevant clauses of IRC:SP:114 by using appropriate
Time period, Importance factor and Response reduction factor. Inertia forces on soil mass for abutments resting on
open foundations shall be calculated by taking Ahs=Z/2 for displacement <25mm and Ahs=50% of Z/2=0.25Z for
displacement >25mm caused by dynamic lateral earth pressure including static component. For abutments
supported on deep foundations (pile/well), Ahs=0.25Z shall be considered.
In this case
PIR = Ahs (Ww+Ws) for open foundation and PIR = Ahs Ws for Pile/Well Foundation
Ww is weight of the base slab only and Ws=weight of soil resting on the base slab/ well or pile cap
(d)
Abutments connected to deck through fixed bearings or through seismic connections (links/reaction
blocks) or integral with superstructure (Open or Pile/Well foundations):This case is similar to the case
215.5.1(c) and Inertia forces shall be calculated in a similar manner, except that elastomer bearings are replaced
by fixed bearings/connection. When abutment is monolithic with either the superstructure or return/wing walls,
Ahs = Z/2 only will be considered without reducing it by 50% irrespective of the type of foundation.
214.5.2 Combination of Inertia Forces-Longitudinal direction:
During verification of the external stability of retaining wall/abutment and design of foundation, the following
two combinations shall be investigated considering the effects of (Paw)dyn + (Paq)dyn and PIR not to be concurrent:
§
§
76
combine 100 percent of the seismic earth pressure {(Paw)dyn+(Paq)dyn} with 50 percent of the inertial force PIR
and
combine 50 percent of the seismic earth pressure {(Paw)dyn+(Paq)dyn}, but not less than the Static active earth
pressure force with 100 percent of inertial force PIR.
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION
The higher of results from these two combinations shall be used for checking the external stability of abutment or
retaining wall & design of foundation. When superstructure is supported on fixed/elastomeric bearings or
monolithic with the abutment, inertia forces on abutment wall, pile or well cap and well shall be considered
additionally as stated in Clause 214.5.1 (c) and 214.5.1 (d) above.
The inertial force associated with the soil mass on the foundation behind the retaining wall/abutment wall is not
added to the active seismic earth pressure when structurally designing the retaining/abutment walls. The basis for
excluding this inertial force is that movement of this soil mass is assumed to be in phase with the structural wall
system with the inertial load transferred through the foundation.
The inertial forces on soil mass and wall mass shall act at their respective CG as shown in Fig. 14C. Value of
seismic coefficient Avs applied to Ww and Ws shall be taken as two third of Ahs and considered in downward or
upward direction.
Fig. 14 C: Seismic Force Diagram for External Stability Check for Cantilever Wall
214.5.3 Combination of Inertia Forces-Transverse direction:
In case of combination of forces in transverse seismic case, 100% inertia force (along transverse direction) shall
be combined with 100% static earth pressure (along longitudinal direction).
Value of Ahs shall be considered same as recommended in 214.5.1 for the purpose of calculation of inertia forces
on wall mass WW and soil mass WS. Inertia forces transferred through superstructure shall be considered
additionally and computed as per IRC:SP:114.
214.5.4 Combination of inertia forces shall be done as per Clause 4.2.2 of IRC:SP:114 for all types of abutments/retaining
walls.
Abutments with pile/well foundations and connected through fixed bearings/connections or monolithic with
superstructure and designed for ductile detailing with R>1, shall also be checked for Capacity design effects as per
Chapter 7 and 8 of IRC:SP:114.
NOTIFICATION
NOTIFICATION NO. 52
Subject: Withdrawal of IRC:45-1972 "Recommendations for Estimating the Resistance of Soil Below the
Maximum Scour Level in the Design of Well Foundations of Bridges"
The IRC:45-1972 "Recommendations for Estimating the Resistance of Soil Below the Maximum Scour Level in the
Design of Well Foundations of Bridges" published by Indian Roads Congress in 1972 stands withdrawn with immediate
effect.
INDIAN HIGHWAYS
SEPTEMBER 2022
77
NOTIFICATION
NOTIFICATION NO. 53
Amendment No.1/IRC:78(Part-2)/June, 2022 (Effective from 1st September, 2022)
To
IRC:78-2020 (Part-2 ) Code of Practice for Limit State Design of Foundations
Sr No.
1
Clause No./ Page no.
Symbols, Latin letters
eB eL
(Page No. 2)
For
Read
eB :Eccentricity of vertical loads in eB : Eccentricity of vertical loads in
transverse direction
transverse direction for double-axis
eccentricity
eL :Eccentricity of vertical loads in eL : Eccentricity of vertical loads in the
longitudinal direction
longitudinal direction for double-axis
eccentricity
78
2
Greek Letter
(Page No. 3)
3
3.2.3
Fig. 3
(Page No. 8)
4
3.2.3
Fig 4
(Page No. 8)
5
Δ
δ
4.3
(below Table 4)
(Page No. 13)
The vertical ground resistance shall
be computed always using Set 1 value
only for materials, in all combinations
for piles subjected to both
compressive and tensile forces.
For materials, the vertical ground
resistance shall always be computed
using Set 1 value only in all
combinations for piles subjected to
both compressive and tensile forces.
6
4.4.1
Line 1
(Page No. 14)
Short pile foundations only
Short pile foundations only,
7
4.5.4
Table 8
(Page No. 17)
CR 6 1.50,1.35,1.30
CR 6 1.90,1.76,1.70
8
4.8.1 Para 1
(Page No. 21)
In order to arrive at the design tensile
resistance of an isolated pile, the load
combinations as per table B.4 of
IRC:6 shall be followed.
In order to arrive at the design tensile
resistance of an isolated pile, the load
combination as per Table B.4 of IRC:6
and Table 10 under Clause 4.8.3.1 of
this code shall be followed.
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION
Sr No.
Clause No./ Page no.
Read
For
9
4.8.3.1
Para 2 line 3
(Page No. 21)
Table 10 for the design shaft tensile Table 10 to arrive at the design shaft
resistance
tensile resistance
10
4.8.3.2
Para 3
CR 3 and CR 4 are the modified partial CR 3 and CR 4 are the modified partial
factors as 1.1 times values mentioned in factors using 1.1 times values
mentioned in Table 7.
Table 7.
11
4.8.3.3/22
Para 3
(Page No. 22)
partial factors, as 1.1
Partial factors, using 1.1
12
4.8.3.4, title
(Page No. 22
Total Uplift Resistance
Total Tensile Resistance
Line 1
The total uplift resistance
The total tensile resistance
Line 2
The uplift resistance of single pile
The tensile resistance of single pile
4.8.3.4 Para 2 Line 1
The uplift resistance of group of piles
The total tensile resistance of group of piles
4.8.3.5
(Page No. 23)
Ultimate design uplift capacity of piles in Ultimate tensile resistance of piles
rock or intermediate Geo-materials
in rock or intermediate Geomaterials
13
The top 300 mm depth of the socket may be
omitted for calculating the uplift capacity
using ground parameters. The ultimate
socket resistance shall be calculated as per
Clause 9 of Appendix 5 of IRC:78 Part-1
The ultimate socket resistance shall be
divided by the ground resistance factor for
socket resistance which may be taken from
Table 9 and model factor 1.15 to obtain the
design resistance. The length of the socket
shall be limited to 6 times the pile diameter.
The frictional resistance capacity of soil
above the socket shall be calculated as per
Clause 4.8.3.1 and added to socket
resistance capacity to arrive at the design
ultimate pull out capacity of pile socketed in
rock. The self weight of pile shall also be
added. The design pull out capacity can also
be estimated from pull out tests. The
correlation factor for pull out test shall be
taken from Table 7 and multiplied by factor
1.1 shall be used to estimate the
characteristic pull out capacity from tests
The method shown in Clause 4.8.3.2 shall be
followed to work out the design uplift
capacity using the correlation factor and
socket resistance factor given in Table 9
from the field test results The total uplift
resistance of block shall be tensile capacity
of all the piles in the group, which is as
follows:
The top 0.3 m depth of the socket may
be omitted for calculating the tensile
resistance using ground parameters.
The ultimate socket resistance shall be
calculated as per Clause 9 of Appendix
5 of IRC:78 Part-1 The ultimate socket
resistance shall be divided by the
ground resistance factor for socket
resistance which may be taken from
Table 9 and model factor 1.15 to obtain
the design resistance. The length of the
socket shall be limited to 6 times the
pile diameter. The frictional resistance
capacity of soil above the socket shall
be calculated as per Clause 4.8.3.1 and
added to socket resistance capacity to
arrive at the design tensile resistance of
pile socketed in rock. The self weight of
pile shall also be added. The tensile
resistance can also be estimated from
pull out tests. The correlation factor for
pull out test shall be taken from Table 7
and multiplied by factor 1.1 shall be
used to estimate the characteristic
tensile resistance from tests The
method shown in Clause 4.8.3.2 shall
be followed to work out the tensile
resistance using the correlation factor
and socket resistance factor given in
Table 9 from the field test results. The
INDIAN HIGHWAYS
SEPTEMBER 2022
79
NOTIFICATION
Sr No. Clause No./ Page no.
For
Read
(Pile capacity of single pile x Number of total tensile resistance of block shall be
piles)
tensile resistance of all the piles in the group,
which is as follows:
(Pile capacity of single pile x Number of
piles)
14
5.1 Para 2,
Line 2
(Page No. 25)
Clause 5.3 of this code.
Clause 5.4 of this code.
15
5.9.2
(Page No. 28)
Add at the end of 1)
For foundation resting over rock the resisting
factor shall be taken as mentioned in Clause
5.6.2.
Explanatory note
16
(Page No. 34)
( D) Foundation Resting on Rock
(D) Foundation Resting on Rock (Cases as
mentioned under (A))
17
2.5 (c), Table 4
(Page No. 40)
≥3
≥5
18
2.10 (A)
(4)
(Page No. 43)
4) Calculation of pile FOS from Dynamic 4) Calculation of pile FOS from Dynamic
tests
tests
Taking tests conducted at two locations
Taking tests conducted at two locations
19
80
2.10 (B)
(4)
(Page No. 43)
Combination 1
DL:LL 50:50 = 1.50 x 1.425 = 2.13
DL:LL 70:30 = 1.50 x 1.395 = 2.09
Combination 1
DL:LL 50:50 = 1.90 x 1.425 = 2.70
DL:LL 70:30 = 1.90 x 1.395 = 2.65
Combination 2
DL:LL 50:50 = 1.50 x 1.15 x 1.70 =2.93
DL:LL 70:30 = 1.50x 1.09 x 1.70 = 2.77
Combination 2
DL:LL 50:50 = 1.90 x 1.15 x 1.70 = 3.71
DL:LL 70:30 = 1.90x 1.09 x 1.70 = 3.52
4) FOS using Dynamic tests
4) FOS using Dynamic tests
Combination 1
DL: LL 50:50 = 1.50 x 1.25 = 1.88 (88%)
DL: LL 70:30 = 1.50 x 1.29 = 1.94 (93%)
On Ground Strength 1.50
Combination 1
DL: LL 50:50 = 1.90 x 1.25 = 2.38 (88%)
DL: LL 70:30 = 1.90 x 1.29 = 2.45 (93%)
On Ground Strength 1.90
Combination 2
DL: LL 50:50 = 1.50 x 1.0 x 1.7 x 0. 85 = 2.16
(74%)
DL: LL 70:30 = 1.50 x 1.0 x 1.75 x 0. 85 = 2.16
(78%)
Ground strength alone 2.16
Combination 2
DL: LL 50:50 = 1.90 x 1.0 x 1.7 x 0.85 =
2.74 (74%)
DL: LL 70:30 = 1.90 x 1.0 x 1.70 x 0.85 =
2.74 (78%)
Ground strength alone 2.74
Factor of safety remains 1.60 and above
for normal methods and for dynamic
methods it will be 2.20. Target for normal
methods is 2.0 for normal loading: 25%
of over stressing when compared to
normal load. Hence can be accepted for
ground resistance factor.
Factor of safety remains 1.60 and above for
normal methods and for dynamic methods
it will be 2.74. Target for normal methods
is 2.0 for normal loading: 25% of over
stressing when compared to normal load.
Hence can be accepted for ground
resistance factor.
INDIAN HIGHWAYS
SEPTEMBER 2022
NOTIFICATION/MEETING SCHEDULE
Sr No. Clause No./ Page no.
20
21
3.11.1(B)
(Page No. 47)
3.11 Last
Para Line 1
(Page No. 47)
For
Read
B) With SV Loading Case
For Combination 1
DL:LL 50:50 = Total FOS = 1.25 x 1.20
x 1.0 = 1.50 (78%)
DL:LL 70:30 = Total FOS =1.29 x 1.20
x 1.0 = 1.55 (82%)
FOS on Soil = 1.20
B) With SV Loading Case
For Combination 1
DL:LL 50:50 = Total FOS = 1.25 x 1.20
x 1.0 = 1.50 (78%)
DL:LL 70:30 = Total FOS =1.29 x 1.20 x
1.0 = 1.55 (82%)
FOS on Soil = 1.20
For Combination 2
DL:LL 50:50 = Total FOS = 1.0 x 1.10
x 1.78 = 1.96 (89%)
DL:LL 70:30 = Total FOS = 1.0 x 1.10
x 1.78 = 1.96 (89%)
FOS on Soil = 1.96
For Combination 2
DL:LL 50:50 = Total FOS = 1.0 x 1.00 x
1.78 = 1.78 (81%)
DL:LL 70:30 = Total FOS = 1.0 x 1.00 x
1.78 = 1.78 (81%)
FOS on Soil = 1.78
Hence Resistance Factor of 1.20 and 1.1 Hence Resistance factors of 1.20 and 1.00
can be taken.
can be taken.
Technical Committee Meeting Schedule for the month of September, 2022
INDIAN HIGHWAYS
SEPTEMBER 2022
81
MoRT&H Circular
82
INDIAN HIGHWAYS
SEPTEMBER 2022
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INDIAN HIGHWAYS
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PUBLISHED ON 28 AUGUST 2022
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