Download - pt slab for high rise building peer am 2009

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Page 1: pt slab for high rise building   peer am 2009

Seismic behavior and modeling of gravity-slab-framing system in concrete core wall high-rise buildings

Tony Yang, Ph.D. Assistant Professor, University of British Columbia

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•  116 Completed (>75m ~= 240 ft.) •  43 Planned •  20 Demolished •  5 under construction •  13 Never built

Source: http://www.emporis.com/

High-rise buildings in San Francisco

(On hold….)

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Concrete core shear wall buildings

MKA

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San Francisco, Rincon Center

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MKA

Concrete core shear wall buildings

Core shear wall

Link beam PT slab

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Concrete core shear wall buildings

http://activerain.com

Gravity column Core wall PT slab

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Structural design

Code design:

•  Design the core wall without the gravity system.

•  Design the gravity system without the seismic effect.

•  Gravity system need to be design for the ductility…

Questions: Is it safe …?

Is it all?

MKA

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PT slab column wall gravity system

UCB

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PT slab column wall gravity system

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PT slab column wall gravity system

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PT slab column wall gravity system

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PT slab column wall gravity system

m1 m2

w

m2

Slab (BC element with lumped plastic hinges).

Wall (BC element)

Column (BC element)

F1, D1 (master) F1, D1 (slaved)

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PT slab column wall gravity system

-0.1 -0.05 0 0.05 -30

-20

-10

0

10

20

30

40

Drift ratio [-]

Forc

e [k

ips]

Experimental Test Analytical Simulation

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Floo

r N

umbe

r Lateral system

Gravity-only system

Nonlinear analytical model

Fiber section

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UCLA – J. Wallace

Modeling the concrete coupling beams

M,θ M,θ

Analytical Experimental

M

θ

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Perform3D – gravity framing systems

A A

Plane A-A view Lump plastic hinge model:

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Nonlinear dynamic analyses  3D bi-directional shaking.  Ground motion are selected based on:

  Database: PEER NGA database.   Magnitude (Mw): 6.5 - 8.   Distance (R): 10 km (0 - 20 km).   Useable periods: > 8 sec.

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Selection of the ground motions

0 1 2 3 4 5 6 7 8 9 10 0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Period [sec]

Sa [g

] CW48WGF (T1 = 4.3 sec)

CapCPM (SF = 2.1) CapFOR (SF = 4.1) CapPET (SF = 2.3) DuzDZC (SF = 1.2) GazGAZ (SF = 1.8) KobAMA (SF = 2.1) KobFKS (SF = 2.5) KobPRI (SF = 1.4) LomLGP (SF = 1.1) LomSTG (SF = 2.5) LomWVC (SF = 2.1) Target spectrum (MCE - SF) Mean (MCE - SF)

0.2 T1 to 1.5 T1

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Variation of EDP vs. story height

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Variation of EDP vs. story height

X S

-9 -8 -7 -6 -5 -4 -3 -2 -1 0 B5

L1

L6

L11

L16

L21

L26

L31

L36

L41

axialForceGCS [kips]

Floo

r num

ber [

-]

x 1e3

GL + GM GL + PushoverX GL + mean GM GL + mean GM ± std GM

CW48WGF

Average = 96% of PushoverX Max = 99% of PushoverX Min = 90% of PushoverX

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Maximum un-factored axial forces

-12 -10 -8 -6 -4 -2 0 B5

L1

L6

L11

L16

L21

L26

L31

L36

L41

axialForceGCS [kips]

Floo

r num

ber [

-]

DL

LL LLred

EQ

-14

x 10 3

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Maximum factored axial forces

-2 -1.8 -1.6 -1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 x 10

4 B5

L1

L6

L11

L16

L21

L26

L31

L36

L41

axialForceGCS [kips]

Floo

r num

ber [

-]

1.4*DL 1.2*DL+1.6*LLred 1.0*DL+0.25*LL+EQ

90% of design load.

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Effect of modeling the gravity system   Change in structural periods and stiffness

T1 T2 T3 CW48NGF 4.72 sec 4.10 sec 2.66 sec CW48WGF 4.27 sec 3.86 sec 2.65 sec

% change in stiffness 22% 13% 1%

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Effect of modeling the gravity system

0 50 100 B5

L1

L6

L11

L16

L21

L26

L31

L36

L41

Floo

r num

ber [

-]

Story Drift – H1 [in.]

0 1e4 2e4 3e4 B5

L1

L6

L11

L16

L21

L26

L31

L36

L41

Core Shear - H1 [kips]

0 1 2 3 x10 7 B5

L1

L6

L11

L16

L21

L26

L31

L36

L41

Core Moment - H2[kip-in.]

CW48WGF CW48NGF

1.5% of building height

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Summary and conclusions  Slab-wall-column framing is a prevalent design.  Experimental tests and analytical simulations

have been conducted to study the seismic effect.  Effect on structural responses:  Stiffness:  Core wall:  Gravity column:

(10% ~ 25% ). Modest change. Insignificant.

a) Potential significance.

b) Simplified plastic analysis.

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Questions and suggestions? Thank you for your attention!

Contact information:

Tony Yang: [email protected]

http://peer.berkeley.edu/~yang/

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PT slab column wall gravity system

Hwang and Moehle (2000) ACI Structural Journal

Beff = 120”

Beff = 80”

Effective slab width:

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PT slab column wall gravity system

8” 120”

1.5” 1.5”

#5 A615 Grade 60 steel @ 12” o.c.

fc’ = 6100 psi (@ 17 days)

67

100

Stress [ksi]

Strain [-]

0.08 0.12

E = 2900 ksi

90

A615 Grade 60 steel rebar:

0

Stress [ksi]

Strain [-] 0.002 0.005

Concrete (fc’ = 6100 psi @ 17 days):

0

6.1

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PT slab column wall gravity system

Plastic rotation [-]

M1

[kip

-in.]

-0.2 -0.1 0 0.1 0.2 -2

-1

0

1

2

-0.1 -0.05 0 0.05 0.1 -4 -3

-2

-1

0 1

x1e3 x1e3

M2

[kip

-in.]

Plastic rotation [-]

M+,θ+