1. UNBONDED POST-TENSIONED HYBRID COUPLED WALLS
Yahya C. KURAMA
University of Notre Dame
Notre Dame, Indiana
Qiang SHEN, Michael MAY (graduate students)
New Developments in Hybrid and Composite Construction
ACI Fall 2001 Convention
October 30, 2001
Dallas, Texas

2. UP COUPLED WALL SUBASSEMBLAGE
steel
concrete PT
anchor
spiral
connection
region
wall region
beam
PT tendon
cover plate
angle
embedded
plate
PT tendon

3. DEFORMED SHAPE AND COUPLING FORCES
contact
region
gap
opening
Vcoupling P z db P lb
Vcoupling
Vcoupling =
P z lb

4. BROAD OBJECTIVES RESEARCH ISSUES RESEARCH PHASES
Investigate feasibility and limitations
Develop seismic design approach
Evaluate seismic response
RESEARCH ISSUES
Force/deformation capacity of beam-wall connection region
Yielding of the PT steel
Energy dissipation
Self-centering
Overall/local stability
RESEARCH PHASES
Subassemblage behavior: analytical and experimental
Multi-story coupled wall behavior: analytical

5. ANALYTICAL WALL MODEL (DRAIN-2DX)
wall beam wall
angle element
beam elements
LEFT WALL REGION
RIGHT WALL REGION
kinematic
constraint
wall-
height
elements
contact
truss
element
slope=
1:3
modeling of wall contact regions
embedded plate
truss
element
fiber
element
kinematic
constraint

6. MATERIAL PROPERTIES compression-only steel fiber
stress
stress
TENSION
TENSION
strain
strain
compression-only steel fiber
compression-only concrete fiber
TENSION
stress
strain
compression-tension steel fiber
TENSION
stress
strain
truss element

7. ANGLE MODEL T Kishi and Chen (1990) seat angle at bolt or PT anchoray
seat angle at
bolt or
PT anchor
tension yielding
axial
force
TENSION
axial
force
TENSION
axial
force
TENSION
Tay =
deformation
deformation
def.
angle model
fiber 1
fiber 2

8. FINITE ELEMENT MODEL (ABAQUS)
beam rotation=3.3%

9. BEAM STRESSES
(ksi)

10. CONCRETE STRESSES
(ksi)
beam
side
PT anchor

11. DRAIN-2DX VERSUS ABAQUS
beam shear (kN)
beam shear (kN)
800
1000
ABAQUS (rigid)
ABAQUS (deformable)
ABAQUS (rigid)
DRAIN-2DX (rigid)
beam rotation (%) 5 5
beam rotation (%)
beam shear (kN)
contact/beam depth
1000
1.0
d = 718 mm b
ABAQUS (deformable)
d = 577 mm
DRAIN-2DX (deformable) b
ABAQUS (deformable)
DRAIN-2DX (deformable) 5 5
beam rotation (%)
beam rotation (%)

12. BEAM-WALL SUBASSEMBLAGEF
L8x8x1-1/8
W21x182
lw = 3.0 m lb = 3.0 m (10 ft) lw = 3.0 m
fpi = 0.6 fpu
ap = 420 mm2
(0.65 in2)

13. LATERAL LOAD BEHAVIOR beam moment (kN.m) beam moment (kN.m) 3000 2500p
PT-yielding M y
flange yld.
cover plate yielding
tension angle yielding
L8x8x1-1/8
decompression
-2500 6 -6 6
beam rotation (%)
beam rotation (%)
beam moment (kN.m)
beam moment (kN.m)
2500
2500
L8x8x3/4
no angle
-2500
-2500 -6 -6 6 6
beam rotation (%)
beam rotation (%)

14. PARAMETRIC INVESTIGATION
DESIGN PARAMETERS RESPONSE PARAMETERS
Beam cross-section
Wall length
Beam length
PT steel area
Initial PT stress
Angle size
Cover plate size
Decompression
Tension angle yielding
Cover plate yielding
Beam flange yielding
PT tendon yielding
beam moment (kN.m)
beam moment (kN.m)
3000
3000
ap=560mm2
bilinear estimation
ap=420mm2
analytical model
ap=280mm2
decompression
decompression
tension angle yielding
tension angle yielding
cover plate yielding
cover plate yielding
beam flange yielding
beam flange yielding
PT tendon yielding
PT tendon yielding
estimation points 8 6
beam rotation (%)
beam rotation (%)

15. PROTOTYPE WALL 8.5 m 8.5 m 8.5 m (28 ft 28 ft 28 ft) 32.6 m (107 ft)
6 m m m m m
(20 ft 20 ft ft ft ft)
3.0m 3.0m 3.0 m
PLAN VIEW
(10 ft 10 ft 10 ft)
W21x182
ap = 398 mm2
(0.612 in2)
fpi = fpu

16. COUPLED WALL BEHAVIOR base moment (kip.ft) base moment (kip.ft) 120000
right wall
two uncoupled walls
left wall
2.5 4
roof drift (%)
roof drift (%)

17. COUPLED WALL BEHAVIOR overturning/base moment (kN.m)
90000
90000
CIP wall w/ UP beams
precast wall w/ UP beams
1st beam gap opening
left wall concrete cracking
left wall gap opening
1st beam gap opening
right wall gap opening
softening of left wall
softening of left wall
right wall concrete cracking
1st beam angle yielding
1st beam cover plate yielding
softening of right wall
softening of right wall
1st wall mild steel yielding
1st wall PT-bar yielding
1st beam angle yielding
1st beam flange yielding
1st beam cover plate yielding
1st beam PT-tendon yielding
1st beam PT-tendon yielding
right wall concrete crushing
two uncoupled walls
two uncoupled walls
right wall in coupled system
right wall in coupled system
left wall in coupled system
left wall in coupled system 3 3
roof drift (%)
roof drift (%)

18. CAST-IN-PLACE WALL PARAMETRIC STUDY
overturning moment (kN.m)
overturning moment (kN.m)
100000
100000
softening of left wall
lw=3.05m
softening of left wall
ws=1.38%
softening of right wall
lw=2.29m
softening of right wall
1st wall mild steel yield
1st wall mild steel yield
ws=1.73%
1st beam angle yield
lw=3.81m
1st beam angle yield
ws=2.07%
1st beam flange yield
1st beam flange yield
1st beam tendon yield
1st beam tendon yield
roof drift (%) 3
roof drift (%) 3
overturning moment (kN.m)
overturning moment (kN.m)
100000
100000
softening of left wall
abp=395mm2
softening of left wall
fbpi=0.625fbpu
softening of right wall
softening of right wall
1st wall mild steel yield
abp=198mm2
1st wall mild steel yield
fbpi=0.525fbpu
1st beam angle yield
abp=593mm2
1st beam angle yield
fbpi=0.725fbpu
1st beam flange yield
1st beam flange yield
1st beam tendon yield
1st beam tendon yield
roof drift (%) 3
roof drift (%) 3

19. PRECAST WALL PARAMETRIC STUDY
overturning moment (kN.m)
overturning moment (kN.m)
100000
100000
softening of left wall
softening of left wall
1st beam angle yield
lw=3.05 m
1st beam angle yield
wp=1.13%
softening of right wall
lw=2.29 m
softening of right wall
wp=1.41%
1st wall PT-bar yield
1st wall PT-bar yield
lw=3.81 m
1st beam flange yield
1st beam flange yield
wp=1.69%
1st beam tendon yield
1st beam tendon yield
right concrete crush
right concrete crush
roof drift (%) 3
roof drift (%) 3
overturning moment (kN.m)
overturning moment (kN.m)
100000
100000
softening of left wall
softening of left wall
1st beam angle yield
abp=395mm2
1st beam angle yield
fbpi=0.625fbpu
softening of right wall
softening of right wall
abp=198mm2
fbpi=0.525fbpu
1st wall PT-bar yield
1st wall PT-bar yield
1st beam flange yield
abp=593mm2
1st beam flange yield
fbpi=0.725fbpu
1st beam tendon yield
1st beam tendon yield
right concrete crush
right concrete crush
roof drift (%) 3
roof drift (%) 3

20. CYCLIC BEHAVIOR 8-story precast wall w/ UP beams
1000
1000
base shear (kips)
base shear (kips)
-1000
-1000 -3 3
-1.5
1.5
roof drift (%)
roof drift (%)
6-story CIP wall w/ UP beams
6-story CIP wall w/ embedded beams
1000
1000
base shear (kips)
base shear (kips)
-1000
-1000
-1.5
1.5
-1.5
1.5
roof drift (%)
roof drift (%)

21. CYCLIC BEHAVIOR CIP wall w/ UP beams precast wall w/ UP beams
80000
80000
overturning moment (kN.m)
overturning moment (kN.m)
-80000
-80000
2.5
2.5
2.5
2.5
roof drift (%)
roof drift (%)
CIP wall w/ embedded beams
CIP wall w/ UP beams w/o angles
80000
80000
overturning moment (kN.m)
overturning moment (kN.m)
-80000
-80000
2.5
2.5
2.5
2.5
roof drift (%)
roof drift (%)

22. DESIGN APPROACH base shear, V (kips) 4500 Vdes Vdes/R Ddes Dsur 3
1st beam angle yielding
Survival EQ
1st beam flange yielding
1st beam PT tendon yielding
wall base concrete crushing
Design EQ
Vdes K
K(R/m)
Vdes/R
Ddes
Dsur 3
roof drift, D (%)

23. MAXIMUM DISPLACEMENT DEMANDF F F
akbe
akbe
[(1+br)Fbe,Dbe]
(Fbe,Dbe)
(brFbe,Dbe) D D D + =
kbe
(1+bs)kbe
bskbe
Bilinear-Elastic (BE)
Elasto-Plastic (EP)
Bilinear-Elastic/
Elasto-Plastic (BP)
br = bs = 1/4, 1/3, 1/2
a = 0.02, 0.10
Moderate and High Seismicity
Design-Level and Survival-Level
Stiff Soil and Medium Soil Profiles
R=[c(m-1)+1]1/c
Ta b c=
Ta T
(Nassar & Krawinkler, 1991)

24. DUCTILITY DEMAND SPECTRA
br = bs = 1/3, a=0.10, High Seismicity, Stiff (Sd) Soil, R=1, 2, 4, 6, 8 (thin thick)
Design EQ (SAC): a=3.83, b=0.87
Survival EQ (SAC): a=1.08, b=0.89
ductility demand, m
ductility demand, m 14 14
regression
BP, mean
3.5
3.5
period, T (sec)
period, T (sec)
Survival EQ (SAC): BP versus EP
Survival EQ (SAC): BP versus BE
ductility demand, m
ductility demand, m 14 14
BP, mean
EP, mean
BE, mean
3.5
3.5
period, T (sec)
period, T (sec)

25. MDOF DYNAMIC ANALYSES (SAC-LA37-2%50yrs)
CIP wall w/ UP beams
precast wall w/ UP beams 3 3
uncoupled walls
uncoupled walls
coupled walls
coupled walls
roof-drift (%)
roof-drift (%) -3 -3
time (seconds) 20
time (seconds) 20
CIP wall w/ embedded beams
CIP wall w/ UP beams w/o angles 3 3
roof-drift (%)
roof-drift (%) -3 -3
time (seconds) 20
time (seconds) 20

26. Elevation View (half-scale)
EXPERIMENTAL PROGRAM
Beam-wall connection subassemblages
Ten half-scale tests (angle, beam, post-tensioning properties)
Elevation View (half-scale)
Objectives
Investigate beam M-q behavior
Verify analy. model
Verify design tools and procedures
L4x8x3/4
load block
W10x68
PT strand
strong floor
lw = 1.5 m lb = 1.5 m (5 ft) lw = 1.5 m
fpi = 0.6 fpu
ap = 140 mm2
(0.217 in2)

27. EXPERIMENTAL SET-UP
actuators
wall
beam
load block

28. SUMMARY AND CONCLUSIONS
Beam Behavior
Analytical models seem to work well
Gap opening governs behavior
Large self-centering, limited energy dissipation
Large deformations with little damage
Bilinear estimation for beam behavior
Experimental verification
Wall Behavior
Level of coupling up to percent
Two-level performance based design approach
~25% larger displacements compared to embedded systems

29. ONGOING WORK ACKNOWLEDGMENTS
Subassemblage tests
Design/analysis of multi-story walls
Dynamic analyses of multi-story walls
ACKNOWLEDGMENTS
National Science Foundation (Dr. S. C. Liu)
University of Notre Dame
CSR American Precast, Inc.
Dywidag Systems International, U.S.A, Inc.
Insteel Wire Products
Ambassador Steel
Ivy Steel & Wire
Dayton/Richmond Concrete Accessories