Project 1_Comparative study of different storey buildings for Seismic forces

Aim: Comparing analysis results of various structural configurations with respect to seismic force using ETAB2018 Software

Introduction:

• Using ETAB2018 doing 10 models with different heights, different column sizes
• Checking Factors influencing the dynamic characteristics of a building
• Checking Factors influencing the Natural Period of a building
• Checking Factors influencing the Mode shape of oscillations
• Using Etab2018 software making model acing loads like dead load, live load, diaphragms etc.

Procedure:

• structural elements sizes
• beam size- 300x400mm -for all model beam size is same
• slab -150mm thick
• column sizes- 400x400mm

- 600x600mm

-800x800mm

-550x300mm

-300x550mm

• bay length on each direction is 4m center to center

• material properties-
• concrete- M30
• steel- fe415
• loading-
• dead load on beams from infill wall- 10kn/m
• live load on floor -3kn/m2
• building are assuming to be pinned based

1) creating model A- 2storey buinding with

column size 400x400mm,

• defining material properties

• defining frame sectoin properties

• defining slab properties

• defining load cases

• defining mass source

• creating model

• run analysis to see deflected shape

2) creating model B- 5storey buinding with

column size 400x400mm

3)creating model-C 5 storey builng with rectangular orianted along X- direction

column size-550x300mm

4)creating model-D

5 storey builng with rectangular orianted along Y- direction

column size-300x550mm

5) creating model-E

10 storey building with varying column size along building height

column size- upper 5 storey 400x400mm

-bottom 5storey 600x600mm

6)creating model-F

10 storey building

column size-600x600mm

7)creating model-G

25-storey building with varrying column size along building height

column size- upper 5 storey 400x400mm

-middle 10 storey 600x600mm

-bottom 10 storey 800x800mm

8)creating model-H

25-storey building

column size-800x800mm

9) creating model-J

25-storey building with imposed mass 10% larger then building H

column size-800x800mm

10)creating model-K

25-storey building with imposed mass 20% larger then building H

column size-800x800mm

Result:-

• CRITERIA	MODEL	RESULT
  Effect of stiffness on time period	Building-E (10storey with varying column size)	1.732sec
  	Building-F (10storey with uniform column size)	1.735sec
  Effect of stiffness on time period	Building-G (25 storey with varying column size)	4.16sec
  	Building-H (25 storey with uniform column size)	4.404sec

building-E

building-F

building-G

building-H

• CRITERIA	MODEL	RESULT
  Effect of mass on time period	Building-H (25 storey with 3Kn/m2 impose load)	4.404sec
  	Building-H (25 storey with 3.3Kn/m2 impose load)	4.414sec
  	Building-H (25 storey with 3.6Kn/m2 impose load)	4.423sec

building-h (25 storey with 3Kn/m2 impose load)

building H (25 storey with 3.3Kn/m2 impose load)

Building h (25 storey with 3.6Kn/m2 impose load)

• CRITERIA	MODEL	RESULT
  Effect of building height on time period	Building-A (2 storey)	0.508sec
  	Building-B (5 storey)	1.053sec
  	Building-F (10 storey)	1.735sec
  	Building-H (25 storey)	4.404sec

  building-A

building-B

building-F

building-H

• CRITERIA	MODEL	RESULT
  Effect of column orientation on time period	Building-B (All floor column size 400x400)	1.053sec
  	Building-c (all floor column size 550x300oriented in X-direction)	1.146sec
  	Building-D (all floor column size 300x500 oriented in Y-direction )	1.121sec

Building-B

building-C

building-D

• CRITERIA	MODEL	RESULT
  Effect of flexural stiffness of structural element on mode shapes	Building-B (flexural stiffness of beams close to nil zero inertia)	2.633 sec
  	Building-B (full flexural stiffness of beams Regular)	1.053sec

building b (flexural stiffness of beams close to nil zero inertia)

• CRITERIA	MODEL	RESULT
  Effect of axial stiffness of vertical members on mode shaps	Building-H (axial cross section for columns is close to nil zero Axial area)	5.981sec
  	Building-H (full axial cross section for columns Regular)	4.404sec

• CRITERIA	MODEL	RESULT
  Effect of degree of fixity at column base on mode shaps	Building-B (column supported pinned regular)	1.053sec
  	Building-B (column support fixed )	0.958sec

  building b (column support fixed )1.053sec