UNBONDED POST-TENSIONED HYBRID COUPLED WALLS Yahya C. KURAMA University of Notre Dame Notre Dame, Indiana Qiang SHEN, Michael MAY (graduate students) New

UNBONDED POST-TENSIONEDHYBRID COUPLED WALLS

Yahya C. KURAMA

University of Notre Dame

Notre Dame, Indiana

Qiang SHEN, Michael MAY (graduate students)

New Developments in Hybrid and Composite ConstructionACI Fall 2001 Convention

October 30, 2001Dallas, Texas

UP COUPLED WALL SUBASSEMBLAGE

beam

PT tendon

connectionregion

PTanchor

embeddedplate

angle

PT tendon

wall regionspiral

cover plate

concretesteel

DEFORMED SHAPE AND COUPLING FORCES

contactregion

gapopening

Vcoupling =P zlb

PP

Vcoupling

Vcoupling

dbz

lb

BROAD OBJECTIVES

• 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

ANALYTICAL WALL MODEL (DRAIN-2DX)

fiberelement

kinematicconstraint

trusselement

wall beam wall

angle elementbeam elements

LEFT WALL REGION RIGHT WALL REGION

kinematicconstraint

wall-heightelements

kinematicconstraint

wall-contactelements

trusselement

slope=1:3

modeling of wall contact regions

embedded plate

MATERIAL PROPERTIES

stress

strain

TENSION

compression-only steel fiber

TENSION

stress

strain

compression-only concrete fiber

TENSIONstress

strain

compression-tension steel fiber

TENSIONstress

strain

truss element

ANGLE MODEL

bolt orPT anchor

T ay

seat angle at tension yielding

fiber 1angle model fiber 2

axialforce

TENSION

def.

axialforce

TENSION

deformation

axialforce

TENSION

deformation

= +

Kishi and Chen (1990)

Tay

beam rotation=3.3%

FINITE ELEMENT MODEL (ABAQUS)

BEAM STRESSES(ksi)

beamsidePT anchor

side

CONCRETE STRESSES(ksi)

DRAIN-2DX VERSUS ABAQUS800

50

ABAQUS (rigid)ABAQUS (deformable)

beam shear (kN)

beam rotation (%)

0 5

d = 718 mm1000

DRAIN-2DX (deformable)

ABAQUS (deformable)

b

d = 577 mmb

beam shear (kN)

beam rotation (%)

contact/beam depth

50

1.0

DRAIN-2DX (deformable)

ABAQUS (deformable)

beam rotation (%)

5

DRAIN-2DX (rigid)

ABAQUS (rigid)

0

1000

beam rotation (%)

beam shear (kN)

BEAM-WALL SUBASSEMBLAGE

W21x182

L8x8x1-1/8

ap = 420 mm2

(0.65 in2)

lw = 3.0 m lb = 3.0 m (10 ft) lw = 3.0 m

F

fpi = 0.6 fpu

LATERAL LOAD BEHAVIOR

0 6-6

0

2500

-2500

L8x8x3/4

0 6-6

0

2500

-2500

L8x8x1-1/8

beam rotation (%)

beam moment (kN.m)

beam rotation (%)

beam moment (kN.m)

0

2500

-25000 6-6

no angle

beam rotation (%)

beam moment (kN.m)

beam moment (kN.m)

Mp

My

cover plate yieldingtension angle yielding

decompression

60

3000 PT-yielding

beam rotation (%)

flange yld.

PARAMETRIC INVESTIGATION

• Beam cross-section • Wall length• Beam length• PT steel area• Initial PT stress• Angle size• Cover plate size

DESIGN PARAMETERS RESPONSE PARAMETERS

• Decompression• Tension angle yielding• Cover plate yielding• Beam flange yielding• PT tendon yielding

3000

0 6

beam moment (kN.m)

beam rotation (%)

analytical modelbilinear estimation

decompression


PT tendon yieldingbeam flange yielding

estimation points

80

3000beam moment (kN.m)

beam rotation (%)

decompression


PT tendon yieldingbeam flange yielding

ap=560mm2

ap=420mm2

ap=280mm2

PROTOTYPE WALL

W21x182

ap = 398 mm2

(0.612 in2)fpi = 0.625 fpu

(10 ft 10 ft 10 ft)

32.6 m (107 ft)

3.0m 3.0m 3.0 m PLAN VIEW

6 m 6 m 6 m 6 m 6 m

8.5

m

8

.5 m

8.5

m

(20 ft 20 ft 20 ft 20 ft 20 ft)

(28

ft

2

8 f

t

2

8 f

t)

COUPLED WALL BEHAVIOR

base moment (kip.ft)

0 2.5

120000

roof drift (%)

coupled wall

right wall

left wall

0 4roof drift (%)

120000base moment (kip.ft)

coupled wall

two uncoupled walls

1st beam PT-tendon yielding

1st beam angle yieldingsoftening of left wall

softening of right wall

1st beam flange yielding

right wall concrete crushing

1st wall PT-bar yielding

left wall gap opening1st beam gap opening

right wall gap opening

1st beam cover plate yielding

left wall in coupled system

right wall in coupled system

two uncoupled walls

precast wall w/ UP beams

roof drift (%)30

90000

overturning/base moment (kN.m)

roof drift (%) 30

90000overturning/base moment (kN.m)

softening of left wall

softening of right wall

1st beam angle yielding

1st beam PT-tendon yielding

1st wall mild steel yielding

left wall concrete cracking1st beam gap opening

right wall concrete cracking

1st beam cover plate yielding

CIP wall w/ UP beams

two uncoupled walls

left wall in coupled system

right wall in coupled system

COUPLED WALL BEHAVIOR

CAST-IN-PLACE WALL PARAMETRIC STUDY

lw=2.29m

lw=3.05m

lw=3.81m

softening of left wallsoftening of right wall

1st beam angle yield

1st beam tendon yield1st beam flange yield

1st wall mild steel yield

roof drift (%)

overturning moment (kN.m)100000

0 3

abp=395mm2

abp=198mm2

abp=593mm2

fbpi=0.625fbpu

fbpi=0.525fbpu

fbpi=0.725fbpu

roof drift (%)

overturning moment (kN.m)

100000

0 3roof drift (%)


0 3

ws=1.73%

ws=1.38%

ws=2.07%

roof drift (%)


0 3













PRECAST WALL PARAMETRIC STUDY

lw=2.29 mlw=3.05 m

lw=3.81 m

wp=1.13%

wp=1.41%wp=1.69%

abp=395mm2

abp=198mm2

abp=593mm2

fbpi=0.625fbpu

fbpi=0.525fbpu

fbpi=0.725fbpu


softening of right wall1st beam angle yield

1st beam flange yield

right concrete crush1st beam tendon yield

1st wall PT-bar yield

roof drift (%)


0 3 roof drift (%)


0 3

roof drift (%)

overturning moment (kN.m)

100000

0 3 roof drift (%)


0 3
















CYCLIC BEHAVIOR

-1.5 0 1.5-1000

0

1000

-1.5 0 1.5-1000

0

1000

-1.5 0 1.5-1000

0

1000

bas

e sh

ear

(kip

s)

roof drift (%)

-1000

0

1000

-3 0 3

bas

e sh

ear

(kip

s)

roof drift (%)

bas

e sh

ear

(kip

s)

roof drift (%)

bas

e sh

ear

(kip

s)

roof drift (%)

8-story precast wall w/ UP beams 6-story precast wall w/ UP beams

6-story CIP wall w/ UP beams 6-story CIP wall w/ embedded beams

2.5 0 2.5-80000

0

80000

roof drift (%)

ove

rtu

rnin

g m

om

ent

(kN

.m)

2.5 0 2.5-80000

0

80000

roof drift (%)

ove

rtu

rnin

g m

om

ent

(kN

.m)

2.5 0 2.5-80000

0

80000

roof drift (%)

ove

rtu

rnin

g m

om

ent

(kN

.m)

2.5 0 2.5-80000

0

80000

roof drift (%)

ove

rtu

rnin

g m

om

ent

(kN

.m)

CIP wall w/ UP beams precast wall w/ UP beams

CIP wall w/ embedded beams CIP wall w/ UP beams w/o angles

CYCLIC BEHAVIOR

base shear, V (kips)DESIGN APPROACH

30

4500

roof drift, (%)

1st beam angle yielding

1st beam flange yielding

wall base concrete crushing

1st beam PT tendon yielding

Design EQ

Survival EQ

KK(R

Vdes

Vdes/R

des sur

MAXIMUM DISPLACEMENT DEMAND

(Nassar & Krawinkler, 1991)

• r = s = 1/4, 1/3, 1/2• = 0.02, 0.10• Moderate and High Seismicity• Design-Level and Survival-Level• Stiff Soil and Medium Soil Profiles

Bilinear-Elastic (BE) Elasto-Plastic (EP) Bilinear-Elastic/

Elasto-Plastic (BP)

+ =

F F F

(Fbe,be)

kbe

(rFbe,be)

skbe

[(1+r)Fbe,be]

(1+s)kbe

kbekbe

R=[c1)+1]1/c

c= +

Ta b

Ta+1 T

14

0 3.5period, T (sec)

14

0 3.5

Design EQ (SAC): a=3.83, b=0.87 Survival EQ (SAC): a=1.08, b=0.89ductility demand,

period, T (sec)

ductility demand,

DUCTILITY DEMAND SPECTRA

0

14

3.5 period, T (sec)

0

14

3.5 period, T (sec)

regressionBP, mean

ductility demand, ductility demand,

EP, meanBP, mean

BE, mean

Survival EQ (SAC): BP versus EP Survival EQ (SAC): BP versus BE

r = s = 1/3, =0.10, High Seismicity, Stiff (Sd) Soil, R=1, 2, 4, 6, 8 (thin thick)

MDOF DYNAMIC ANALYSES (SAC-LA37-2%50yrs)CIP wall w/ UP beams precast wall w/ UP beams

CIP wall w/ embedded beams CIP wall w/ UP beams w/o angles

-3

0

3

time (seconds)

roo

f-d

rift

(%

)

0 20-3

0

3

time (seconds)

roo

f-d

rift

(%

)

coupled wallsuncoupled walls

coupled wallsuncoupled walls

0 20

-3

0

3

time (seconds)

roo

f-d

rift

(%

)

-3

0

3

time (seconds)

roo

f-d

rift

(%

)

0 20 0 20

EXPERIMENTAL PROGRAM

Objectives• Investigate beam M-

behavior• Verify analy. model• Verify design tools

and procedures

• Beam-wall connection subassemblages

• Ten half-scale tests (angle, beam, post-tensioning properties)

W10x68PT strand

L4x8x3/4

ap = 140 mm2

(0.217 in2)

lw = 1.5 m lb = 1.5 m (5 ft) lw = 1.5 m

strong floor

fpi = 0.6 fpu

Elevation View (half-scale)

load block

EXPERIMENTAL SET-UP

beam

wall

load block

actuators

SUMMARY AND CONCLUSIONSBeam 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 60-65 percent• Two-level performance based design approach• ~25% larger displacements compared to embedded

systems

ONGOING WORK• 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

Documents

UNBONDED POST-TENSIONED HYBRID COUPLED WALLS Yahya C. KURAMA University of Notre Dame Notre Dame, Indiana Qiang SHEN, Michael MAY (graduate students) New