seismic behavior and modeling of gravity- slab-framing
TRANSCRIPT
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
• 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….)
Concrete core shear wall buildings
MKA
San Francisco, Rincon Center
MKA
Concrete core shear wall buildings
Core shear wall
Link beam PT slab
Concrete core shear wall buildings
http://activerain.com
Gravity column Core wall PT slab
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
PT slab column wall gravity system
UCB
PT slab column wall gravity system
PT slab column wall gravity system
PT slab column wall gravity system
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)
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
Floo
r N
umbe
r Lateral system
Gravity-only system
Nonlinear analytical model
Fiber section
UCLA – J. Wallace
Modeling the concrete coupling beams
M,θ M,θ
Analytical Experimental
M
θ
Perform3D – gravity framing systems
A A
Plane A-A view Lump plastic hinge model:
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.
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
Variation of EDP vs. story height
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
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
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.
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%
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
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.
Questions and suggestions? Thank you for your attention!
Contact information:
Tony Yang: [email protected]
http://peer.berkeley.edu/~yang/
PT slab column wall gravity system
Hwang and Moehle (2000) ACI Structural Journal
Beff = 120”
Beff = 80”
Effective slab width:
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
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+