1) Concrete core shear wall buildings are a common structural system for high-rise construction. These buildings consist of concrete core walls connected to floor slabs and gravity columns. 2) Previous studies have shown that modeling the interaction between the gravity framing system (slabs and columns) and the lateral load-resisting core walls can increase the estimated stiffness of the overall structure by 10-25% compared to modeling the systems separately. 3) Nonlinear dynamic analyses of buildings with modeled gravity-core wall interaction have found modest changes in structural response quantities like story drift, core shear, and core moment, compared to analyses without this interaction.

1. 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

2. • 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….)

3. Concrete core shear wall buildings
MKA

4. San Francisco, Rincon Center

7. MKA
Concrete core shear wall buildings
Core shear wall
Link beamPT slab

8. Concrete core shear wall buildings
http://activerain.com
Gravity columnCore wall
PT slab

9. 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

10. PT slab column wall gravity system
UCB

11. PT slab column wall gravity system

12. PT slab column wall gravity system

13. PT slab column wall gravity system

14. 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)

15. PT slab column wall gravity system
-0.1 -0.05 0 0.05
-30
-20
-10
0
10
20
30
40
Drift ratio [-]
Force[kips]
Experimental Test
Analytical Simulation

16. FloorNumber
Lateral
system
Gravity-only
system
Nonlinear analytical model
Fiber section

17. UCLA – J. Wallace
Modeling the concrete coupling beams
M,θ
M,θ
Analytical
Experimental
M
θ

18. Perform3D – gravity framing systems
A
A
Plane A-A view
Lump plastic hinge model:

19. 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.

20. 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

21. Variation of EDP vs. story height

22. 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]
Floornumber[-]
x 1e3
GL + GM
GL + PushoverX
GL + mean GM
GL + mean GM ± std GM
CW48WGF
Average = 96% of PushoverXMax = 99% of PushoverXMin = 90% of PushoverX

23. Maximum un-factored axial forces
-12 -10 -8 -6 -4 -2 0
B5
L1
L6
L11
L16
L21
L26
L31
L36
L41
axialForceGCS [kips]
Floornumber[-]
DL
LL
LLred
EQ
-14
x 10
3

24. 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]
Floornumber[-]
1.4*DL
1.2*DL+1.6*LLred
1.0*DL+0.25*LL+EQ
90% of design load.

25. 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%

26. Effect of modeling the gravity system
0 50 100
B5
L1
L6
L11
L16
L21
L26
L31
L36
L41
Floornumber[-]
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
7B5
L1
L6
L11
L16
L21
L26
L31
L36
L41
Core Moment - H2
[kip-in.]
CW48WGF
CW48NGF
1.5% of building height

27. 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.

28. Questions and suggestions?Thank you for your attention!
Contact information:
Tony Yang: yangtony2004@gmail.com
http://peer.berkeley.edu/~yang/

29. PT slab column wall gravity system
Hwang and Moehle (2000) ACI Structural Journal
Beff = 120”
Beff = 80”
Effective slab width:

30. 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

31. 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+