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.
