Project 1_Comparative study of different storey buildings for Seismic forces
Comparative study of different storey buildings for Seismic forces
- AIM : To compare the results of various structural configuration with respect to seismic force on E-TABS.
Introduction : The project consist 10 different building with various configuration having bay length of 4.00m on X & Y directions. All columns in each storey are same in size and all beams are of same size of 300x400mm.
2.PROCEDURE:
- Draw/model initialization by grid method.
- Defining material and sections.
- Draw Column, beam and slab.
- Define mass source, load patterns and assign live loads, wall loads etc.
- Select Beams and slabs assign live loads and wall loads as:
- Assign load combinations:
- Select Slab and assign Diaphragm:
Run analysis :
- Repeat the procedures for all 10 type building configurations.
RESULTS :
- Building E
- Building F
- Building G
- Building H
- Building J
- Building K
- Building B
- Building B (Zero inertia)
- Building B (Fixed joint)
- Building H (Zero axial area)
RESULTS
Criteria | Model | Analysis result | Conclusion |
Effect of stiffness on time period | Building – E (10 storey with varying column size) | 1.77 S | No considerable changes in Time period. |
Building – F (10 storey with uniform column size) | 1.77 S | ||
Effect of stiffness on time period | Building – G (25 storey with varying column size) | 4.19 S | Slightly higher Time period in uniform than varying column size. |
Building – H (25 storey with uniform column size) | 4.43 S | ||
Effect of Building height on time period | Building – H (25 storey with 3 KN/Sqm imposed load) | 4.43 S | No considerable changes in Time period. |
Building – J (25 storey with 3.3 KN/Sqm imposed load) | 4.43 S | ||
Building – K (25 storey with 3.6 KN/Sqm imposed load) | 4.44 S | ||
Effect of Building height on time period | Building – A (2 storey ) | 0.58 S | Higher Time period for higher number of storey’s. |
Building – B (5 storey ) | 1.16 S | ||
Building – F (10 storey ) | 1.77 S | ||
Building – H (25 storey with uniform column size) | 4.43 S | ||
Effect of Column orientation on time period | Building – B (All floor Coulmn size 400x400 mm, 5 storey ) | 1.16 S | Uniform column size has less Time period than non-uniform column size. |
Building – C (All column size 500x300, orientation in X direction ) | 1.36 S | ||
Building – D All column size 300x500, orientation in Y direction) | 1.34 S | ||
Effect of mass on Time period | Building – J (With imposed mass 10% larger ) | 4.42 S | Higher the mass, higher is the time period. |
Building – K (With imposed mass 20% larger ) | 4.44 S |
Criteria | Model | Case | Analysis result | Conclusion |
Effect of Flexural stiffness of structural elements on mode shapes | Building – B (Beam with 10% stiffness ) | Flexural stiffness of beams close to nil (Zero inertia) | 2.64 S | Lower the stiffness, higher Time period. |
Flexural stiffness of beam (Regular) | 1.16 S | |||
Effect of Flexural stiffness of structural elements on mode shapes | Building – H (Column with 10% stiffness ) | Axil cross section for columns is close to nil (Zero axial area) | 5.93 S | Lower the stiffness, higher Time period. |
Full axial cross section for columns (Regular) | 4.43 S | |||
Effect of degree of fixity at Column base on Mode shape | Building – B | Column support pinned (Regular) | 1.16 S | Fixed support has less Time period than Pin support. |
Column support fixed | 0.87 S |