static and dynamic analysis by etabs

8/19/2019 Static and Dynamic Analysis by ETABS

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Linear Elastic Static andDynamic Analyses by

ETABS

THE UNIVERSITY OF HONG KONG Dr. Ray Su

Department of Civil Engineering


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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

G r i d

l i n e s

storey

column lines

Wall

E.L. Wilson (2000)

Three Dimensional Static and Dynamic Analysis of Structures, A PhysicalApproach with Emphasis on Earthquake Engineering, Computers and Structures, Inc. BerkeleyCalifornia, USA.

Node

Procedure for using ETABS


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Static Lateral Load and Free Vibration AnalysisExample 1

300 x 500 RC beam

300 x 500 RC beam

300 x 500 RC beam

300 x 300RC 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

109N/m2X

Z


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Start ETABSSelect Unit


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


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Define Material Properties

For dyn.analyses

For staticanalyses (weightwill be generatedautomatically

Unit=N/m3

)


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Define Frame Sections(Beam)


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Define Frame Sections(Column)


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Define the Structural Form(Column)

(Select COLUMN Properties)


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Define the Structural Form(Beam)

(Select BEAM Properties)


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Define the Structural Form

A i M


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

Select Beam Elements

Assi n Mass


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

A i S t R t i t


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Assign Support Restraints



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Assign Point Loads


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Assign Point Loads

WIND

Assign Point Loads


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Assign Point Loads

Perform the Analysis


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Perform the Analysis

Allowable DOF

Present Results


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Present Results(Show Mode Shapes)

Mode 1= 0.69 sec (ETABS)

Mode 1= 0.67 sec (from Hand Calculation)

Present Results


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r s nt su ts(Show Mode Shapes)

Mode 3+Dynamic Response = Mode 1 Mode 2+

Mode 3+

T1

=0.69 s T2

=0.23 s T3

=0.14 s

(0.67s) (0.25s) (0.18s)By Excel calculation (p111)

Present Results


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(Show Output Data-Displacement)

WIND

Present Results


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Present Results(Show Output Data-Displacement)

WINDWINDWINDWINDWINDWINDWINDWIND

Present Results


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(Show Output Data-Displacement)

0 10 20 30 40 50 60 70

Displacement (mm)

0

1

2

3

S t

o r e y

Hand Calculation

ETABS

Example 2


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p

Model 2 9-storey MRF Building

93

82.5

72

62

51.541

31.5

21.511

3.5m

6m 6m 6m

typical RC beam 300 x 500

typical RC column 500 x 500

Example 2


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pETABS Model

Example 2


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pFundamental Period & Displacement


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

S t o r e y

Hand Calculation

ETABS

Mode Shape (first mode)




Example 3


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Model 3 9-storey Wall Building

93

82.5

72

62

51.541

31.5

21.5

11

3.5m

4m

0.3m thick x 4m long RC wall

Example 3


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Define Wall Sections

Membrane action Bending action

Deformedshape

X

Z

X

Z

Example 3


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Draw Rectangular Areas

Example 3E B d l


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ETABS Model

Example 3F d t l P i d & Di l t


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Fundamental Period & Displacement

0 10 20 30 40 50 60 70

Displacement (mm)

0

1

2

3

4

5

6

7

8

9

S t o r

e y

Hand Calculation

ETABS

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




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Example 4ETABS M d l


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ETABS Model

Rigid Link

Example 4Fundamental Period & Displacement


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Fundamental Period & Displacement

0 10 20 30 40

Displacement (mm)

0

1

2

3

4

5

6

7

8

9

S t o

r e y

Hand Calculation

ETABS




Analysis Results(Show Mode Shapes)


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(Show Mode Shapes)

Mode 1

T1=0.81 s

Mode 2

T2=0.17 s

Mode 3

T3=0.07 s

Excel calculation T 1

= 0.80s ,

T 2

=0.17s

T 3

=0.06s

Acceleration Response SpectraFor HK Rock sites


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For HK Rock sitesReturn period = 475 years

Medium-field Far-field

Return period = 2475 years

Near-field Far-field

Spectrum & Time History AnalysesResponse Spectrum & Time History Functions


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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

S p e c t r a l A c c e l e r a t i o n ( g )

0 5 10 15 20

Time (sec)

-1.0

-0.5

0.0

0.5

1.0

A c c e l e r a t i o n ( m / s ^ 2 )

Medium Field

(Return Period: 475 yrs)10% exceedance

in 50 yrs

(5% damping ratio) 10MF18.dat

Spectrum & Time History AnalysesResponse Spectrum & Time History Functions


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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

S p e c t r a l A c c e l e r a t i o n ( g )

0 10 20 30 40

Time (sec)

-1.0

-0.5

0.0

0.5

1.0

A c c e l e r a t i o

n ( 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


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Define Response Spectrum Functions

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


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Define Response Spectrum Cases

2

Spectrum Analysis-Example 4 (ETABS)Results-Displacement


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p

(m)

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


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y

(N)

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


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y

m/s^2


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


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(m)

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


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(N)

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


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0 5 10 15 20Displacement (mm)

0

1

2

3

4

5

6

7

8

9

S t o r e y

Spectrum Anlysis

Time History Analysis

0 100 200 300 400Storey Shear (kN)

1

2

3

4

5

6

7

8

9

S t o r e y

Spectrum Anlysis


Displacement Storey Shear

Medium Field, Return Period: 475 years (5% damping ratio)

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


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Displacement Storey Shear

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

0 5 10 15 20 25 30Displacement (mm)

0

1

2

3

4

5

6

7

8

9

S t o r e y

Spectrum Anlysis


0 100 200 300 400Storey Shear (kN)

1

2

3

4

5

6

7

8

9

S t o r e y

Spectrum Anlysis



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End

Assignment 2Lateral Load Analysis of a Frame using ETABS


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b

d y

x

P3

P2

P1

h

h

h

s X

Z

A two-dimensional reinforcedconcrete frame building subjected toa set of lateral loads is shown. Thesectional sizes

of beams (b ×d ) and

columns (x ×y ), the floor height

(h ),the beam span

(s ) and the appliedlateral loads

(P 1

, P 2

, P 3

) are listed inTable 1. The material properties of

all structural members are constant:the Young's Modulus E = 25GPa

andPoisson's ratio v = 0.2. For lateralload analysis, you may assume the

concrete weight per unit volume to be0 N/m3.

Pinnedsupports



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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 50 704 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

Table 1. Dimension and Loading Schedule



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Setup the computer model of the building using the computer softwareETABS

(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

(Δroof

/ H b

)≤

1/500, where H b

is thebuilding height and Δ

roof

is the roof lateral displacement; and(e) suggest four practical ways to reduce the drift ratio

of the building.

Due date:8th April 2013

static and dynamic analysis by etabs

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