PEER-CSSC tall building case studies: Concrete core...

DEPARTMENT OF CIVIL ENGINEERING

UNIVERSITY OF BRITISH COLUMBIA, VANCOUVER

PEER-CSSC tall building case studies: Concrete core wall building

Tony Yang, Ph.D.

Assistant Professor,

University of British Columbia, Vancouver

Acknowledgements:

Jack Moehle and Yousef Bozorgnia(PEER), Andy Fry and John Hooper (MKA), Graham Powell (CSI)

2010 LATBSDC Annual meeting, May 7th 2010

Introduction

PEER SCCS Tall Building Systems

Concrete core shear wall buildings

MKA

Concrete core shear wall buildings

MKA

Core shear wall

Link beamPT slab

Prototype model

MKA

4 stories(≅ 48’)

• Residential building in Downtown Los Angeles.

42 stories (≅ 430’)

228’ 227’

108’

107’

A

A

View A-A

Building design

Building 1A(Code design)

Building 1B(PBEE design)

Building 1C(PBEE+ design)

• Designed using IBC 2006.

• Designed using 2008 LATBSDC procedure.

• Designed using PEER TBI guideline.

• All provisions were followed except the

height limit.

• All provisions were followed. Except: 1) Vmin was waived. 2) SLE was checked using 25-yr EQ (w ζ = 2.5%) instead of 43-yr EQ (w ζ = 5%). No more than 20% of the elements are allowed to reach 150% of the code specified capacity.

• Similar to 1B design Except: 1) SLE was check 43-yr EQ (w ζ = 2.5%). 2) All ductile elements such as the coupling beams and flexural yielding of the concrete walls are allowed to reach 150% of the code specified capacity.






• Designed using PEER TBI draft guideline.

Performance-based design guideline for tall

buildings

Building design






• Designed using PEER TBI draft guideline.

• B4 – L24: 24”• L25 – Roof: 21”

• B4 – L13: 28” (N-S)32” (E-W)

• L14 – L31: 24”• L32 – Roof: 21”

• B4 – L13: 32” (N-S)36” (E-W)

• L14 – L31: 24”• L32 – Roof: 21”

Wall

thic

kness

Building design: Wall vertical reinforcement

1A

1B

1C

MKA

Building design: Coupling beam reinforcement

MKA

1A

1B

1C

Building design comparison

1A: Code 1B: PBEE 1C: PBEE+

Wall: Strong Stronger Strongest

Coupling beam:

Stronger Stronger Strong

1st mode Period:

T1X = 5.2 sec

T1Y = 4.0 sec

T1X = 4.8 sec

T1Y = 3.6 sec

T1X = 4.6 sec

T1Y = 3.5 sec

24” 24” 28” 28” 32” 32”

Nonlinear analytical model

3D nonlinear dynamic finite element model (Perform3D).

Ignored the gravity system.


Basement walls below grade were modeled using elastic shear wall elements (Eeff = 0.8 E)


Slabs below grade were modeled using elastic shear shell element (Eeff

= 0.25 E)


• Shear wall flexural behavior: Nonlinear fiber wall element with expected material property.

• Shear wall shear behavior: Nonlinear shear material.

0 2 4 6 8 10 12 14

Displacement Ductility

0

1

2

3

Vtest/Vn,ACI

PCA

HSC - SP1 Wallace test data

Wallace, Massone, Orakcal - 2006

1.5 Vn

Vexp/

Vn

Curvature ductility


UCLA – J. Wallace

Analytical

Experimental

M

θ

Nonlinear dynamic analyses

3D bi-directional shaking.

GM: 5 Hazard levels.

Period [sec]0 2 4 6 8 10

0

0.5

1

1.5

2

Targ

et S

a [g]

SLE-25 (25 yr)

SLE-43 (43 yr)

DBE (475 yr)

MCE (2475 yr)

OVE (4975 yr)

Nonlinear dynamic analyses

15 pairs of GM were selected and amplitude scaled for each hazard level.

Structural response

Structural response (MCE)

0 0.5 1 1.5 2

x 104

B4

L2

L7

L12

L17

L22

L27

L32

L37

L42

Core shear H1 [kips]

PEERTBI-1AM

Floor number [-]

MCE

0 0.5 1 1.5 2

x 104

B4

L2

L7

L12

L17

L22

L27

L32

L37

L42


Floor number [-]

PEERTBI-1BM

MCE

0 0.5 1 1.5 2

x 104

B4

L2

L7

L12

L17

L22

L27

L32

L37

L42


Floor number [-]

PEERTBI-1CM

MCE

1B has 20% more core shear force than 1A and 1C.

Demand vs. Capacity

• Normalized probability density function (pdf):

0

1

2

3

4

5

6x 10

-3

Maximum shear force [kips]

pdf

[-]

Demand

Capacity

D>C

• Let X = C - D

• When X < 0

� Failure.

• Using basic probability theory:

µX = µC - µD

σX = √(σC2 + σD

2)

Safety index

• P(system failure) = P(X):

-100 0 100 200 300 400 500 600 7000

0.5

1

1.5

2

2.5

3

3.5x 10

-3

X

pdf

[-]

Probability of failure

Area under the curve = probability of failure.

βXσX, where βX = the safety index.

X = 0

X = µX

Reserved capacity – Wall 2 shear stress (MCE)

-0.5 0 0.5 10

5

10

15

20

25

30

35

40

45

50

X - reserved strength [ksi]

Floor Number [-]

PEERTBI-1AM Wall 2

MCE

-0.5 0 0.5 1 1.50

5

10

15

20

25

30

35

40

45

50

X - reserved strength [ksi]

Floor Number [-]

PEERTBI-1BM Wall 2

MCE

0 0.5 1 1.5 20

5

10

15

20

25

30

35

40

45

50

X - reserved strength [ksi]Floor Number [-]

PEERTBI-1CM Wall 2

MCE

βx = 1.7

βx = 1.4 βx = 6.0


0 2 4 6 8L2

L7

L12

L17

L22

L27

L32

L37

L42

CB1D [%]

PEERTBI-1AM

Floor number [-]

MCE

0 2 4 6 8L2

L7

L12

L17

L22

L27

L32

L37

L42

CB1D [%]

Floor number [-]

PEERTBI-1BM

MCE

0 2 4 6 8L2

L7

L12

L17

L22

L27

L32

L37

L42

CB1D [%]

Floor number [-]

PEERTBI-1CM

MCE


0 2 4 6B3

L3

L8

L13

L18

L23

L28

L33

L38

L43

NodeXYZ-ISDRatioH1 [%]

PEERTBI-1AM

Floor number [-]

MCE

0 2 4 6B3

L3

L8

L13

L18

L23

L28

L33

L38

L43


Floor number [-]

PEERTBI-1BM

MCE

0 2 4 6B3

L3

L8

L13

L18

L23

L28

L33

L38

L43


Floor number [-]

PEERTBI-1CM

MCE


0 0.5 1 1.5 2B3

L3

L8

L13

L18

L23

L28

L33

L38

L43

WallStrain01 [%]

PEERTBI-1AM

Floor number [-]

MCE

0 0.5 1 1.5 2B3

L3

L8

L13

L18

L23

L28

L33

L38

L43

WallStrain01 [%]

Floor number [-]

PEERTBI-1BM

MCE

0 0.5 1 1.5 2B3

L3

L8

L13

L18

L23

L28

L33

L38

L43

WallStrain01 [%]

Floor number [-]

PEERTBI-1CM

MCE

-0.25 -0.2 -0.15 -0.1 -0.05B3

L3

L8

L13

L18

L23

L28

L33

L38

L43

WallStrain01 [%]

PEERTBI-1AM

Floor number [-]

MCE

-0.25 -0.2 -0.15 -0.1 -0.05B3

L3

L8

L13

L18

L23

L28

L33

L38

L43

WallStrain01 [%]

Floor number [-]

PEERTBI-1BM

MCE

-0.25 -0.2 -0.15 -0.1 -0.05B3

L3

L8

L13

L18

L23

L28

L33

L38

L43

WallStrain01 [%]

Floor number [-]

PEERTBI-1CM

MCE


Amplitude scaled vs. synthetic motions

0 1 2 3 4 5 6B3L3L8L13L18L23L28L33L38L43


OVE - Scaled GM

PEERTBI-1AM

0 1 2 3 4 5 6B3L3L8L13L18L23L28L33L38L43


OVE - Simulated GM

0 1 2 3 4 5 6B3L3L8L13L18L23L28L33L38L43


PEERTBI-1BM

0 1 2 3 4 5 6B3L3L8L13L18L23L28L33L38L43


0 1 2 3 4 5 6B3L3L8L13L18L23L28L33L38L43


PEERTBI-1CM

0 1 2 3 4 5 6B3L3L8L13L18L23L28L33L38L43



0 0.5 1 1.5 2

x 104

B4L2L7L12L17L22L27L32L37L42

SectionCore-ForceH1 [kips]

OVE - Scaled GM

PEERTBI-1AM

0 0.5 1 1.5 2

x 104

B4L2L7L12L17L22L27L32L37L42


OVE - Simulated GM

0 0.5 1 1.5 2

x 104

B4L2L7L12L17L22L27L32L37L42


PEERTBI-1BM

0 0.5 1 1.5 2

x 104

B4L2L7L12L17L22L27L32L37L42


0 0.5 1 1.5 2

x 104

B4L2L7L12L17L22L27L32L37L42


PEERTBI-1CM

0 0.5 1 1.5 2

x 104

B4L2L7L12L17L22L27L32L37L42



0 2 4 6 8L2L7L12L17L22L27L32L37L42

CB1D [%]

OVE - Scaled GM

PEERTBI-1AM

0 2 4 6 8L2L7L12L17L22L27L32L37L42

CB1D [%]

OVE - Simulated GM

0 2 4 6 8L2L7L12L17L22L27L32L37L42

CB1D [%]

PEERTBI-1BM

0 2 4 6 8L2L7L12L17L22L27L32L37L42

CB1D [%]

0 2 4 6 8L2L7L12L17L22L27L32L37L42

CB1D [%]

PEERTBI-1CM

0 2 4 6 8L2L7L12L17L22L27L32L37L42

CB1D [%]

Summary and conclusions

A 42-story residential concrete core wall building was designed using three design procedures.

The response of the structures under 5 levels of earthquake shaking was analyzed.

Structural design:

Wall thickness:

Wall vertical reinforcement:

Coupling beam reinforcement:

Structural period:

Structural response:

Wall stress safety index:

Coupling beam demand:

Inter-story drift and wall edge strain:

1A < 1B < 1C

1A < 1B < 1C

1C < 1A ~ 1B

1C < 1B < 1A

1B < 1A < 1C

1A < 1B < 1C

1C < 1B < 1A

Summary and conclusions

Amplitude scaled motions vs. simulated motions:

Story drift:

Core wall forces:

Coupling beam rotation:

This leads to the need for additional research to identify the characteristic of the ground motion which promotes the inelastic action in the coupling beams.

No significant difference.

No significant difference.

Amplitude scaled > simulated.

Question?Thank you for your attention!

Contact information:

Tony [email protected]://peer.berkeley.edu/~yang

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