Presentation on theme: "OBJECTIVE To present a MTLAB program for conducting three dimensional dynamic analysis of multistory building by utilizing a simple and ‘easy to understand’"— Presentation transcript:
1A MATLAB COMPUTER PROGRAM FOR 3-DIMENSIONAL DYNAMIC ANALYSIS OF MULTISTORY BUILDINGS
2OBJECTIVETo present a MTLAB program for conducting three dimensional dynamic analysis of multistory building by utilizing a simple and ‘easy to understand’ plane frame analysis program.To extend the program to do dynamic response spectrum analysis of buildings.
3Why MATLAB ?MATLAB has built-in functions that performs various computational tasks. This reduces, substantially, the program size.Matrix operation in MATLAB are conducted similar to scalar operation.With MATLAB graphic capability, it possible, with a little programming effort, to obtain a graphic display of the results includingstructure geometry,bending and shear force diagrams,deformed shape … etc.
5Shear an Moment Diagrams in a Member Deformed Shape
6Structural and General Purpose FE Software: SAP2000ETABSSTAAD/proOTHERS : ANSYS, ABAQUS, ….ETC
7BUILDING MODELS FOR SEISMIC ANALYSIS Three dimensional fully detailed finite element model of the building structure very expensiveThree dimensional frame model large DOFThree dimensional frame model with rigid diaphragm constraint 3 DOF at each floorA set of orthogonal (two-way) planar frameswith rigid diaphragm constraintPlane frame structure regular and symmetric building
8THREE DIMENSIONAL FRAME WITH RIGID DIAPHRAGM CONSTRAINT ASSUMTIONS:1. The floor diaphragm is rigid in its own plane. This Allows the horizontal displacements at a floor level to be defined in terms of floor horizontal translations and rotation about a vertical axis.2. Building Structure Is Represented by a Set of Orthogonal planar Frames.
91. RIGID DIAPHRAGM APPROXIMATION Mass center3 DOF at each floor+ 3 DOF at each node
101. Identify Building Frames Analysis Procedure:Six planar frameTwo different types1. Identify Building FramesTypical Frame
112. Construct Global Stiffness Matrix for each Typical frame 3. Apply displacement constraint to horizontal degrees of freedom at each level eliminate horizontal degrees of freedom but one at each floor
124. Apply static condensation to eliminate all degrees of freedom but horizontal ones Number of degrees of freedom=Number of floor.Static Condensation
135. Construct the global stiffness matrix for the 3D model by applying rigid diaphragm constraints to each plane frame stiffness matrices using the Number of degrees of freedom=3*Number of floor.Apply to frames in x-directionApply to frames in y-direction
18CONCLUSIONSBuilding Analysis using plane frame analysis programs with constraints gives results which are comparable to 3-dimensional analysisA plane frame representation of a three dimensional building structure is easier for visualization and preparation of dataMATLAB is a powerful means that could be used for programming simple equations of design to the complicated structural analysis programs.