1. PRECAST CONCRETE COUPLED WALL SYSTEMS
Brad Weldon
Yahya C. (Gino) Kurama
University of Notre Dame
PCI Daniel P. Jenny Research Fellowship
PCI Committee Days
April 24, 2004

2. REINFORCED CONCRETE COUPLED WALLS
wall beam wall
Paulay and Priestley 1991
mechanisms of shear resistance
in reinforced concrete coupling beams
Coupling Degree TL
CD 
Mw1+Mw2+TL
Mw1 L
Mw2 T
C=T

3. PRECAST CONCRETE COUPLING BEAMS
wall
confinement PT
anchor
connection
region
wall region
angle
precast beam
beam
PT tendon
confined
concrete
PT duct
PT tendon
beam

4. DEFORMED SHAPE AND COUPLING FORCES
contact
region
gap
opening
Vcoupling
reference line P z db P lb
Vcoupling
beam Pz V @
coupling l b

5. OBJECTIVES
Develop new system based on experimental and analytical studies
Develop seismic design/analysis guidelines and tools, and recommendations for application

6. Precast Coupling Beams
OUTLINE
Steel Coupling Beams
Experimental program
Analytical model and verification
Precast Coupling Beams
Advantages
Parametric studies (DRAIN-2DX)
Design approach

7. Elevation View (half-scale)
STEEL BEAM TESTS
Eleven half-scale coupled wall subassemblages (angle, beam, post-tensioning properties)
Elevation View (half-scale)
test wall region
L4x8x5/8
and reaction fixture
Objectives
Investigate
M-q behavior
Verify analy. models
Verify design tools and procedures
load block
W10x68
PT strand
strong floor
lw=1.5 m lb=1.5 m (5 ft) lw=1.5 m
ap=140 mm2
(0.217 in2)
fpi=0.6fpu

8. TEST SET-UP
actuators
loading block
wall
region
beam
reaction
block

10. ANGLE FRACTURE
Beam rotation = 9%
Test 5
Test 5
Test 2

11. CYCLIC BEHAVIOR OF STEEL COUPLING BEAM
applied shear force, kips (kN) 60
(267)
measured
(-267)
-60
-10 10
beam chord rotation, %

12. ANALYTICAL WALL MODEL (DRAIN-2DX)

13. VERIFICATION OF MODEL
applied shear force, kips (kN) 60
(267)
measured
predicted
(-267)
-60
-10 10
beam chord rotation, %

14. POST-TENSIONED COUPLED WALLS
Unbonded post-tensioning is a promising and feasible method to couple concrete walls (up to percent coupling)
Large self-centering, considerable energy dissipation
Large deformations with little damage
The analytical models and design tools/procedures work well
Shift focus towards precast beams

15. PRECAST ADVANTAGES Simpler beam-to-wall joints
Central location of PT strands
Fire and environmental protection
Higher friction resistance against shear sliding
Favorable tolerances for construction
Cost-efficient

16. PARAMETRIC STUDY DRAIN-2DX (Half-Scale Subassemblages)
Beam Depth (in)
Angle
PT Strands
Gage Length (in)
Aspect Ratio 14
L8x4x1/2 3
3.21 5 4
L8x4x5/8 18
2.5
Varied Parameters:
beam depth
amount of PT
angle size
gage length
aspect ratio

17. TEST SPECIMENS (Half-Scale)
Beam Depth (in)
Angle
PT Strands
Gage Length (in)
Aspect Ratio
Parameter 14
L8x4x1/2 3 5
3.21
Baseline Test 4 ap
L8x4x5/8 18
2.5
Depth, aspect ratio

18. TEST SPECIMEN CROSS-SECTIONS (Half-Scale)
L8x4x1/2
L8x4x1/2
14”
14” 7” 7”
L8x4x5/8
L8x4x1/2
14”
18” 7” 7”

19. DRAIN-2DX SPECIMEN BEHAVIOR
D = 14” L8x4x1/2 PT = 3
D = 14” L8x4x1/2 PT = 4 60 60
(267)
(267)
applied shear force,
kips (kN)
applied shear force,
kips (kN)
(-267)
(-267)
-60
-60
-8.0
8.0
-8.0
8.0
beam chord rotation, (%)
beam chord rotation, (%)
D = 14” L8x4x5/8 PT = 4
D = 18” L8x4x5/8 PT = 4 80 80
(356)
(356)
applied shear force,
kips (kN)
applied shear force,
kips (kN)
(-356)
(-356)
-80
-80
-8.0
8.0
-8.0
8.0
beam chord rotation, (%)
beam chord rotation, (%)

20. FINITE ELEMENT MODEL (ABAQUS)

21. DRAIN-2DX VERSUS ABAQUS
beam shear, kips (kN)
contact depth/depth
300 1
(1335)
ABAQUS
DRAIN-2DX
ABAQUS
DRAIN-2DX 7 7
beam rotation, %
beam rotation, %

22. MINIMUM PRINCIPAL STRESSES

23. MAXIMUM PRINCIPAL STRESSES
If we take a look at the Smax Principal stresses, we see the tensile stresses that are developed in the system. Anything in red, is greateer than the tension strength of concrete and critical for shear design. However, to take advantage of our unique system, we are using abaqus to help in the shear design.

24. BEAM DESIGN longitudinal reinforcement thru ducts for angle connection
PT duct
transverse reinforcement
confined concrete

25. BEAM DESIGN beam end view beam side view transverse reinforcement
confined concrete
PT duct
beam end view
beam side view
longitudinal reinforcement

26. BEAM TO WALL CONNECTION
wire mesh
L8x4x1/2
thru bolt
grout
PT strand
confined concrete

27. CURRENT STATUS
Finalizing design
Laboratory set-up
Begin testing this summer

28. ACKNOWLEDGMENTS Precast/Prestressed Concrete Institute
University of Notre Dame
Industry Participants
Cary Kopczynski & Company
StresCore Inc.
Dywidag Systems International, U.S.A, Inc.
Insteel Wire Products
Dayton/Richmond Concrete Accessories