Partially Post-Tensioned Precast Concrete Walls

Partially Post-TensionedPartially Post-TensionedPrecast Concrete WallsPrecast Concrete Walls

Yahya C. (Gino) KuramaYahya C. (Gino) Kurama

Assistant ProfessorAssistant Professor

University of Notre DameUniversity of Notre Dame

Notre Dame, Indiana, USANotre Dame, Indiana, USA

American Concrete Institute Spring 2003 ConventionAmerican Concrete Institute Spring 2003 ConventionVancouver, CanadaVancouver, Canada

April 2, 2003April 2, 2003

POST-TENSIONED PRECAST CONCRETE WALLPOST-TENSIONED PRECAST CONCRETE WALLanchorage

spiralreinforcement

wall panel

horizontaljointunbonded

PT bars

foundation

reinforcement bondedwire mesh

unbondedPT bar

spiral

precast wall with full PT

BEHAVIOR UNDER LATERAL LOADSBEHAVIOR UNDER LATERAL LOADS

gap opening

HYSTERETIC BEHAVIORHYSTERETIC BEHAVIOR base shear, kips (kN)

roof drift, %

0 1 2

800(3558)

-800(-3558)

-1-2

VERTICALLY JOINTED WALLSVERTICALLY JOINTED WALLS

Priestley et al.Perez et al.KuramaPall et al.

friction or metallic-yield damper

DISPLACED SHAPEDISPLACED SHAPE

WALLS WITH PARTIAL POST-TENSIONINGWALLS WITH PARTIAL POST-TENSIONING

unbondedPT bar

bondedmildbar

bondedmild bar

precast wall with partial PT

unbondedPT bar

ENERGY DISSIPATIONENERGY DISSIPATION

mild steelyielding

PARTIALLY POST-TENSIONED PRECAST FRAMEPARTIALLY POST-TENSIONED PRECAST FRAME

column

beam

PT tendon

mild steel bar

fiber reinforced grout

trough

beam-to-column joint

Cheok et al.Priestley et al.Stanton et al.Nakaki et al.

OBJECTIVESOBJECTIVES

• Investigate precast wall systems with PT steel and mild steel

• Develop seismic design approach

• Evaluate seismic response

• Prototype walls and expected behavior Prototype walls and expected behavior

• Seismic design approach and evaluationSeismic design approach and evaluation

• Summary and conclusionsSummary and conclusions

OUTLINE

• Four fully post-tensioned wallsFour fully post-tensioned walls

• Four walls with only mild steel (emulative walls) Four walls with only mild steel (emulative walls)

• Four partially post-tensioned wallsFour partially post-tensioned walls

PROTOTYPE WALLS

PLAN LAYOUT OF PROTOTYPE BUILDINGSPLAN LAYOUT OF PROTOTYPE BUILDINGS

N

gravity loadframe

wall

invertedT-beamL-beamcolumn

8 x 24 ft = 192 ft (58.5 m)40

+ 3

0 +

40

= 1

10 f

t

hollow- corepanels

lateral loadframe

(33.

5 m

)

4 story building, high seismicity 6 story building, high seismicity

10 story building, high seismicity 6 story building, medium seismicity

FULLY POST-TENSIONED WALLSFULLY POST-TENSIONED WALLS

55 ft

20 ft (6 m)

81 ft

20 ft (6 m)

133 ft

26 ft (8 m)

81 ft

20 ft (6 m)

(17 ft)

(25 ft)

(41 ft)

(25 ft)

4 storyhigh seismicity



6 storymedium seismicity

Wall PH410 ft (3 m)

CL

fpi=0.60-0.65fpu

Ap=1.49in2 (961mm2)#3 spirals

Wall PH610 ft (3 m)

CL

Wall PH10

13 ft (4 m)

CL

Wall PM6

10 ft (3 m)

CL

12in.(305mm)

12in.(305mm)

12in.(305mm)

12in.(305mm)

sp=7.3% fpi=0.60-0.65fpu

Ap=1.49in2 (961mm2)#3 spiralssp=7.3%

fpi=0.625fpu

Ap=1.49in2 (961mm2)#3 spiralssp=1.8%fpi=0.60-0.65fpu

Ap=1.49in2 (961mm2)#3 spiralssp=7.3%

FULLY POST-TENSIONED WALLSFULLY POST-TENSIONED WALLS

EMULATIVE WALLSEMULATIVE WALLS

Wall EH4

12in.

10 ft (3 m)

16 pairs CLNo. 8 bars

5 pairsNo. 5 bars

@ 2.25 in. @ 18 in.

Wall EH6

10 ft (3 m)


5 pairsNo. 5 bars

@ 2.5 in. @ 18 in.

Wall EH10

13 ft (4 m)


6 pairsNo. 5 bars

@ 2.25 in. @ 18 in.

Wall EM6

10 ft (3 m)


5 pairsNo. 5 bars

@ 5.25 in. @ 18 in.

(305mm)

12in.(305mm)

12in.(305mm)

12in.(305mm)

(@ 57 mm) (@ 457 mm) (@ 63 mm) (@ 457 mm)

(@ 57 mm) (@ 457 mm) (@ 133 mm) (@ 457 mm)

PARTIALLY POST-TENSIONED WALLSPARTIALLY POST-TENSIONED WALLS

Wall HH6-25

10 ft (3 m)


5 pairsNo. 5 bars

@ 5.5 in. @ 18 in.

Wall HH6-50

10 ft (3 m)


5 pairsNo. 5 bars

@ 5.5 in. @ 18 in.

Wall HH6-75

10 ft (3 m)


5 pairsNo. 5 bars

@ 3.5 in. @ 18 in.

Wall HM6-50

10 ft (3 m)

CL8 pairsNo. 5 bars

@ 17 in.

12in.(305mm)

12in.(305mm)

12in.(305mm)

12in.(305mm)

(@ 140 mm) (@ 457 mm) (@ 140 mm) (@ 457 mm)

(@ 89 mm) (@ 457 mm) (@ 432 mm)

ANALYTICAL WALL MODEL

fiberelement

kinematicconstraint

trusselement

-100 (690)

0

100 (690)

-0.08 0 0.08

stress, ksi (MPa)

strain

0

7 (48)

0.006

stress, ksi (MPa)

strain

160 (1103)

stress, ksi (MPa)

strain

120 (827)

0.03510

MILD STEEL

PT STEEL CONCRETE

WALL BEHAVIOR UNDER MONOTONIC LOADS

0 3 0 3

0 20 3

Wall PH4Wall EH4

Wall PM6

Wall EM6Wall HM6-50Wall PH10

Wall EH10

Wall PH6Wall HH6-25Wall HH6-50Wall HH6-75Wall EH6

1500base shear, kips (kN)

roof drift, %


roof drift, %



roof drift, %

(6672) (4448)

(4448) (2224)

roof drift, %

SIX STORY WALLS IN HIGH SEISMICITYSIX STORY WALLS IN HIGH SEISMICITY

-1000

0

1000

-3 0 3

base shear, kips (kN)

roof drift, %

Wall PH6(4448)

(-4448)

0

-3 0 3

Wall EH6

-1000


(4448)

(-4448)

roof drift, %

Wall HH6-25 Wall HH6-50

0

-3 0 3

Wall HH6-75

-1000


(4448)

(-4448)

roof drift, %

-3 0 3


roof drift, %-3 0 3


roof drift, %

NORMALIZED INELASTIC ENERGY DISSIPATIONNORMALIZED INELASTIC ENERGY DISSIPATION

-1000

0

1000

-3 0 3


roof drift, %

Dh

Ue

-c

-c

Dh

Ue

dh =

ksec

(4448)

(-4448)

NORMALIZED INELASTIC ENERGY DISSIPATIONNORMALIZED INELASTIC ENERGY DISSIPATION

0

0.5

1

1.5

2

3

Wall PH4Wall EH4

(dh = Dh / Ue)

cycle roof drift,

0

0.5

1

1.5

2

3

(dh = Dh / Ue)

cycle roof drift,

0

0.5

1

1.5

2

3

(dh = Dh / Ue)

cycle roof drift,

0

0.5

1

1.5

2

2

(dh = Dh / Ue)

cycle roof drift, %

Wall PH10Wall EH10

Wall PH6Wall HH6-25Wall HH6-50Wall HH6-75Wall EH6

Wall PM6Wall HM6-50Wall EM6

DYNAMIC RESPONSEDYNAMIC RESPONSE

-2.5

0

2.5

0 15

roof drift, %

time, seconds-2.5

0

2.5

0 15

roof drift, %

time, seconds

-2.5

0

2.5

0 15

roof drift, %

time, seconds-1.5

0

1.5

0 15

roof drift, %

time, seconds

PH4EH4

PH10EH10

PH6HH6-25

HH6-75EH6

PM6HM6-50EM6

HH6-50NOSYPGA=0.97g

NOSYPGA=0.97g

NOSYPGA=0.97g

NOSYPGA=0.39g

0

0.2

0.4

0.6

0.8

1.0

0.2 0.4 0.6 0.8 1normalized mild steel ratio

normalized maximum roof drift

0

PH6 HH6-25 HH6-50 HH6-75 EH6

average

REDUCTION IN MAXIMUM ROOF DRIFTREDUCTION IN MAXIMUM ROOF DRIFT

0

2

4

6

8

0.5 1

average number of drift peaks

normalized amplitude of drift peak

0

2

4

6

8

0.5 1



0

2

4

6

8

0.5 1



0

2

4

6

8

0.5 1



WALL PH4WALL EH4

WALL PH10WALL EH10

WALL PM6WALL HM6-50WALL EM6

WALL PH6WALL HH6-25

WALL HH6-75WALL HH6-50

WALL EH6

REDUCTION IN NUMBER OF DRIFT PEAKSREDUCTION IN NUMBER OF DRIFT PEAKS

• Prototype wallsPrototype walls

• Expected behavior Expected behavior

• Seismic design approach and evaluationSeismic design approach and evaluation

• Summary and conclusionsSummary and conclusions

OUTLINE

FIRST MODE REPRESENTATIONFIRST MODE REPRESENTATION

-1.5

0

1.5

0 4 8 12 16time, seconds

roof drift, %

first modetotal

Wall HW1SAC LA25, PGA=0.87g

SDOF REPRESENTATION

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

+=

F F

(Fbe,be)

kbe

(rFbe,be)

skbe

kbe

Bilinear-Elastic/ Elasto-Plastic (BP)

F

[(1+r)Fbe,be]

(1+s)kbe

kbe

MDOF MODEL SDOF MODEL

-2000

0

2000

-3 0 3


roof drift, %

(8896)

(8896)-2000

0

2000

-3 0 3


roof drift, %

(8896)

(8896)

0.5 1 1.5 2 2.5 3 3.50

2

Los Ang., SD soil, survival-level (SAC LA21-40)

AVG spectrum

4

period, seconds

5% damping

SAC GROUND MOTIONSSAC GROUND MOTIONSpseudo-acceleration, g

SDOF/MDOF PEAK DISPLACEMENTSDOF/MDOF PEAK DISPLACEMENT

50 100 (381) 150

0.2

0.4

0.6

0.8

1.0

1.2

0

SDOF/MDOF maximum displacement ratio

maximum incremental velocity, in/sec (cm/sec)

Wall HW1SAC LA21- 40

mean

DUCTILITY DEMANDDUCTILITY DEMAND

(Nassar & Krawinkler, 1991)

• s = r = 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)

+=

F F

(Fbe,be)

kbe

(rFbe,be)

skbe

kbe

R=[c1)+1]1/c

c= +

Ta b

Ta+1 T

(Farrow and Kurama, 2001)

Bilinear-Elastic/

Elasto-Plastic (BP)

F

[(1+r)Fbe,be]

(1+s)kbe

kbe

DUCTILITY DEMAND SPECTRA (Farrow and Kurama, 2001)

14

0 3.5period, seconds

14

0 3.5

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

period, seconds

ductility demand,

0

14

3.5 period, seconds0

14

3.5 period, seconds

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)

NONLINEAR DEMAND SPECTRANONLINEAR DEMAND SPECTRA

T = 0.5 sec.a = -0.71b = 0.94

=1

(linear-elastic)2

48

2

4

8

T = 1.5 sec.a = -0.71b = 0.94

=1(linear-elastic)

0 (39) 100

0.5

1

1.5

0

0.5

1

1.5

demand displacement, cm (in.)(39) 100

demand acceleration, g demand acceleration, g

demand displacement, cm (in.)

DESIGN OBJECTIVES – SURVIVAL LEVELDESIGN OBJECTIVES – SURVIVAL LEVEL

baseshear

roof drift

immediateoccupancy (t=1.19%)

collapseprevention (t=2.17%)

WALL WH1 WALL WH2

WALLS HW1 AND HW2WALLS HW1 AND HW2

Wall WH1

11 ft (3.35 m)


7 pairsNo. 5 bars

@ 2.5 in. @ 18 in.

Wall WH2

10 ft (3 m)


6 pairsNo. 5 bars

@ 2.5 in. @ 18 in.

12in.(305mm)

12in.(305mm)

(@ 63 mm) (@ 457 mm)

(@ 63 mm) (@ 457 mm)

WALL HW1WALL HW1

1

2

3

0 50 100 (381) 150

maximum roof drift, %

maximum incremental velocity, in/sec (cm/sec)

t=1.19%

mean=1.13%

WALL WH2WALL WH2

0

0.5

1

1.5

2

2.5

33.5

50 100

maximum roof drift, %

(381) 150maximum incremental velocity, in/sec (cm/sec)

t=2.17%

mean=1.85%

CONCLUSIONSCONCLUSIONS

Energy Dissipation

• Mild steel reinforcement yielding in tension and compression

Design Approach

• MDOF SDOF Nonlinear demand spectra

• Target drift

Seismic Response Evaluation

• Maximum drift reduced below target drift

• Significant scatter in results

National Science FoundationNational Science Foundation CAREER-Program CAREER-Program

CMS 98-74872CMS 98-74872

Program DirectorsProgram DirectorsDr. S. C. LiuDr. S. C. Liu

Dr. S. MaCabeDr. S. MaCabe

Documents

Partially Post-Tensioned Precast Concrete Walls