Static and Dynamic Analysis by ETABS

Linear Elastic Static and

Dynamic Analyses by

ETABS

THE UNIVERSITY OF HONG KONG

Dr. Ray Su



Select Unit



Define Grid and Storey Data



Define Material Properties



Define Frame, Wall or Slab Sections



Define Structural Form



Assign Mass



Assign Restraints



Assign Loadings



Perform Analysis



Present Results

Get started with ETABS

Grid li nes

storey

column lines

Wall

E.L. Wilson (2000) Three Dimensional Static and Dynamic Analysis of Structures, A Physical Approach with Emphasis on Earthquake Engineering, Computers and Structures, Inc. Berkeley California, USA.

Node

Static Lateral Load and Free Vibration Analysis Example 1 300 x 500 RC beam 300 x 500 RC beam 300 x 500 RC beam 300 x 300 RC column 3.5m 3.5m 3.5m 6.0 m 16 tonne (Mass) 16 tonne 16 tonne

fixed base fixed base

93 kN

62 kN

31 kN

Model 1

3-storey RC Building

E=27.4×109_N/m2

X Z

Start ETABS Select Unit

Define Grid and Storey Data (Uniformly Spaced Grid and Storey Data)

Define Material Properties For dyn. analyses For static analyses (weight will be generated automatically Unit=N/m3₎

Define Frame Sections (Beam)

Define Frame Sections (Column)

Define the Structural Form (Column)

Define the Structural Form (Beam)

Assign Mass (16Tonnes=16000kg; 16000/6=2667 kg/m)

Assign Mass (16000/6=2667 kg/m)

Assign Point Loads

Perform the Analysis

Present Results (Show Mode Shapes)

Mode 1= 0.69 sec (ETABS)

Present Results (Show Mode Shapes)

Mode 3

+

Dynamic Response =

Mode 1

+

Mode 2

+

Mode 3

T

=0.69 s

T

=0.23 s

T

=0.14 s

(0.67s) (0.25s) (0.18s)

Present Results (Show Output Data-Displacement)

Present Results (Show Output Data-Displacement)

WIND WIND WIND WIND WIND WIND WIND WIND

Present Results (Show Output Data-Displacement)

0 10 20 30 40 50 60 70 Displacement (mm) 0 1 2 3 Storey Hand Calculation ETABS

Example 2

Model 2

9-storey MRF Building

93 82.5 72 62 51.5 41 31.5 21.5 11 3.5m 6m 6m 6m typical RC beam 300 x 500 typical RC column 500 x 500

Example 2 ETABS Model

Example 2 Fundamental Period & Displacement

Mode 1= 1.43 sec (ETABS)

Mode 1= 1.40 sec (Hand Calculation)

0 10 20 30 40 50 60 70 80 90 Displacement (mm) 0 1 2 3 4 5 6 7 8 9 St ore y Hand Calculation ETABS

Mode Shape (first mode)

Mode 1= 1.43 sec (ETABS)

Mode 1= 1.40 sec (Hand Calculation)

Example 3

Model 3

9-storey Wall Building

93 82.5 72 62 51.5 41 31.5 21.5 11 3.5m 4m

Example 3 Define Wall Sections

Membrane action Bending action

Deformed shape X Z X Z

Example 3 Draw Rectangular Areas

Example 3 ETABS Model

Example 3 Fundamental Period & Displacement

0 10 20 30 40 50 60 70 Displacement (mm) 0 1 2 3 4 5 6 7 8 9 Storey Hand Calculation ETABS

Mode 1= 1.12 sec (ETABS) more flexible, usually more accurate

Mode 1= 1.06 sec (Hand Calculation)

Example 4

Model 4

9-storey Dual-System

93 82.5 72 62 51.5 41 31.5 21.5 11 3.5m link

Example 4 ETABS Model

Example 4 Fundamental Period & Displacement

0 10 20 30 40 Displacement (mm) 0 1 2 3 4 5 6 7 8 9 Storey Hand Calculation ETABS

Mode 1= 0.81 sec (ETABS)

Mode 1= 0.77 sec (Hand Calculation)

Analysis Results (Show Mode Shapes)

Mode 1

T

=0.81 s

Mode 2

T

=0.17 s

Mode 3

T

=0.07 s

Acceleration Response Spectra For HK Rock sites

Return period = 475 years

Medium-field Far-field

Return period = 2475 years

Spectrum & Time History Analyses Response Spectrum & Time History Functions

0.0 0.5 1.0 1.5 2.0 2.5 3.0 Period (sec) 0.0 0.1 0.2 0.3 Spe c tral Ac c e ler a tio n ( g ) 0 5 10 15 20 Time (sec) -1.0 -0.5 0.0 0.5 1.0 Acceleration (m /s^2)

Medium Field (Return Period: 475 yrs)

10% exceedance in 50 yrs

Spectrum & Time History Analyses Response Spectrum & Time History Functions

0.0 0.5 1.0 1.5 2.0 2.5 3.0 Period (sec) 0.0 0.1 0.2 0.3 Spectral Acceleration (g) 0 10 20 30 40 Time (sec) -1.0 -0.5 0.0 0.5 1.0 Acceleration (m /s^2) 02FF18.dat Far Field (Return Period: 2475 yrs)

2% exceedance in 50 yrs (5% damping ratio)

Spectrum Analysis-Example 4 (ETABS) Define Response Spectrum Functions

Spectrum Analysis-Example 4 (ETABS) Define Response Spectrum Cases

Spectrum Analysis-Example 4 (ETABS) Results-Displacement

Spectrum Analysis-Example 4 (ETABS) Results-Storey Shear

Time History Analysis-Example 4 (ETABS) Define Time History Functions

Time History Analysis-Example 4 (ETABS) Define Time History Cases

Time History Analysis-Example 4 (ETABS) Results-Displacement

Time History Analysis-Example 4 (ETABS) Results-Storey Shear

Comparison of Simulation Results (ETABS) Spectrum Analysis & Time History Analysis

0 5 10 15 20 Displacement (mm) 0 1 2 3 4 5 6 7 8 9 Storey Spectrum Anlysis Time History Analysis

0 100 200 300 400 Storey Shear (kN) 1 2 3 4 5 6 7 8 9 Stor ey Spectrum Anlysis Time History Analysis

Displacement

Storey Shear

Comparison of Simulation Results (ETABS) Spectrum Analysis & Time History Analysis

Displacement

Storey Shear

Far Field, Return Period: 2475 years (5% damping ratio)

0 5 10 15 20 25 30 Displacement (mm) 0 1 2 3 4 5 6 7 8 9 Storey Spectrum Anlysis Time History Analysis

0 100 200 300 400 Storey Shear (kN) 1 2 3 4 5 6 7 8 9 Stor ey Spectrum Anlysis Time History Analysis

Assignment 2 Lateral Load Analysis of a Frame using ETABS

b d y x P3 P2 P1 h h h s X Z

A two-dimensional reinforced

concrete frame building subjected to

a set of lateral loads is shown. The

sectional sizes

of beams (

b

×

d

) and

columns (

x

×

y

), the

floor height

(

h

),

the

beam span

(

s

) and the

applied

lateral loads

(

P

,

P

,

P

) are listed in

Table 1. The material properties of

all structural members are constant:

the Young's Modulus

E

= 25GPa

and

Poisson's ratio

v

= 0.2

. For

lateral

load analysis

, you may assume the

concrete weight per unit volume to be

0 N/m

_.

Pinned supports

Assignment 2 Lateral Load Analysis of a Frame using ETABS

Last number of your U.No. h (mm) s (mm) b×d (mm) x×y (mm) P1 (kN) P2 (kN) P3 (kN) 0 3500 6000 300×500 450×550 20 40 70 1 3500 6000 300×500 450×550 30 50 70 2 3500 6000 350×550 500×500 20 40 70 3 3500 6000 350×550 500×500 30 50 70 4 3500 6000 350×550 500×600 30 50 70 5 4000 6000 300×500 450×550 20 40 70 6 4000 6000 300×500 450×550 30 50 70 7 4000 6000 350×550 500×500 20 40 70 8 4000 6000 350×550 500×500 30 50 70 9 4000 6000 300×500 500×600 30 50 70

Setup the computer model of the building using the computer software

ETABS

(which is available in Manusell

Laboratory) and

(a) determine the

deformed shape

of the frame;

(b) show the

bending moment diagram

of the frame;

(c) check the

global force equilibrium

of the frame;

(d) check if the

drift ratio

(

Δ

/

H

) ≤

1/500, where

H

is the

building height and

Δ

is the roof lateral displacement; and

(e) suggest four practical ways to

reduce the drift ratio

of the building.

Assignment 2 Lateral Load Analysis of a Frame using ETABS