PROJECT REPORT
COMPARATIVE STUDY OF DIAGRID STRUCTURAL SYSTEM WITH A CONVENTIONAL SYSTEM
COMPARATIVE STUDY OF DIAGRID STRUCTURAL SYSTEM WITH A CONVENTIONAL SYSTEM
BUILDING DETAILS
SR. NO.
DESCRIPTION
GEOMETRY
1
Dimensions of Building
42m X 42m
2
Height of Building
82 m
3
No. of Stories
G+25
4
Storey Height
3.3m
5
Type of Structure
Compare Diagrid system & Conventional system
6
Degree of Diagrid Element
63
7
Dead Load
Frame, Shell & Cladding
8
Live Load
5 KN/m²
9
Load Combination
Gravity + Lateral Loads
10
Types of Analysis
Static & Dynamic analysis FEM, Modal analysis, P-∆
11
Code Based
Indian Standards
BUILDING MATERIAL
SI.NO
MATERIALS
PROPERTIES
1
Grade of Concrete
M40 & M50
2
Rebars
HYSD 500 & HYSD 550
3
Steel
Fe345
4
Non Structural Walls
Light weight blocks
5
Glazing panels
Glass sheets
SECTION PROPERTIES
SI.NO
SECTIONS
Frame sections Beams
SIZES
ISWB 600 of Fe345
Steel Tube 1000X1000X30
Columns
Circular 1000mm of M50
Braces (Diagrid System)
Steel Tube 1100X1100X30
Wall sections
Shear walls
300mm thick of M50
Slab sections
General slab
200mm thick of M40
Tall commercial buildings are primarily a response to the intense pressure on the available land. Advances in materials,
construction technology, analytical methods and structural systems for analysis and design accelerated the development of tall
structures.
The lateral loading due to wind and earthquake is the major factor that causes the design of high-rise buildings. These lateral
loads are resisted by exterior structural system or interior structural system. The lateral load resisting systems that are widely
used are mainly rigid frame, shear wall, wall-frame, braced tube system, outrigger system, diagrid system and tubular system.
Recent trend shows that the Diagrid structural system is becoming popular in the design of tall buildings due to its
inherent structural and architectural advantages.
Diagrid is an exterior structural system in which all perimeter vertical columns are eliminated and consists of only inclined
columns on the façade of the building.
Shear and over-turning moment developed are resisted by axial action of these diagonals compared to bending of vertical
columns in framed tube structure.
Vertical columns in the core are designed for carrying gravity loads only and the diagrid is useful for
both gravity and lateral loading.
The diagonal members in diagrid structures act both as inclined columns and as bracing elements
and due to their triangulated configuration, mainly internal axial forces arise in the members.
Diagrid structures do not need high shear rigidity cores because shear can be carried by
the diagrids located on the perimeter.
Diagrid structures do not need high shear rigidity cores because shear can be carried by
the diagrids located on the perimeter.
Perimeter “diagrid” system saves approximately 20 percent structural steel weight when compared
to a conventional moment-frame structure.
Members that transfer both lateral and gravity loads through axial action.
Can be made of steel , concrete , timber and composite materials.
Usually steel diagonal members are used.
MAX. STORY DISPLACEMENT IN SEISMIC
DIAGRID SYSTEM
CONVENTIONAL SYSTEM
19.2mm MAX.
34.5mmMAX.
MAX. STORY DISPLACEMENT IN WIND
DIAGRID SYSTEM
5.8 MAX.
CONVENTIONAL SYSTEM
8.3MAX.
MAX. STORY DRIFT
DIAGRID SYSTEM
CONVENTIONAL SYSTEM
0.000249 MAX.
0.000432 MAX.
MAX. STORY STIFFNESS
DIAGRID SYSTEM
CONVENTIONAL SYSTEM
1620750.16 MAX.
2138218.43MAX.
GUIDELINE FOR FUNDAMENTAL TIME PERIOD
DIAGRID SYSTEM
CONVENTIONAL SYSTEM
0.897sec
1.466sec.
DIAGRID SYSTEM
CONVENTIONAL SYSTEM
Seismic=20696.0067 KN
Seismic=245588.9574 KN
Wind=7257.7126 KN
Wind=8926.7785 KN
DIAGRID SYSTEM
CONVENTIONAL SYSTEM
Max. Moments=441597.4711 KN-m
Max. Moments=511010.6398
BASE SHEAR RESULTS
RESULTS
Story Shear in Seismic=20696KN
Max. Axial Force=63311.0869KN
Story Shear in Seismic=23951KN
Max. Axial Force=79065.3321KN
Max. Joint Displacement=15.843mm
Max. Joint Displacement=36.167mm
Max. Element Joint Force=26.123KN
Max. Element Joint Force=46.123KN
Max. Element Joint Moment=85.321KN-m
Max. Element Joint Moment=101.047KN- m
DEFORMED SHAPE
DIAGRID SYSTEM
CONVENTIONAL SYSTEM
RESULTANT DISPLACEMENT
DIAGRID SYSTEM
CONVENTIONAL SYSTEM
Dynamic Behavior for Diagrid system
Dynamic Behavior for Conventional system
BENDING MOMENT DIAGRAM
Diagrid System
Conventional System
AXIAL FORCE DIAGRAM
Diagrid System
Conventional System
CONCLUSION
The Diagrid structures have mostly column free exterior and interior, hence free and clear, unique floor plans are Possible.
One of the best structural system for high rise buildings especially irregular shaped (tilted,
twisted, freeform etc.)
Using Diagrid we can built skyscrapers even without inner core providing vast floor area. The Leaden hall Building in London is the first
skyscraper without a bearing inner core thanks to diagrid structural system.
Diagrids help in sustainable development as amount of construction material required is less
and energy is saved due to less obstruction to incoming light at the periphery of building.
The diagrid Structures are aesthetically dominant.
Skyscraper structural failure, as it is such an important/ prominent topic, can be minimized in a Diagrid design. A Diagrid has better ability to
redistribute load than a Moment Frame skyscraper.Thus creating a deserved appeal for the Diagrid in today’s landscape of building.
Vertical columns are almost eliminated and both shear and bending stiffness must be provided by diagonals, a balance between this
two conflicting requirements should be searched for defining the optimal angle of the diagrid module.
Perimeter “diagrid” system saves approximately 20 percent structural steel weight when compared to a conventional moment-frame
structure.
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