39
DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI Convention, Palm Springs, California, October 17-20, 1999

DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

Embed Size (px)

Citation preview

Page 1: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS

Michael G. Allen

Yahya C. Kurama

University of Notre Dame

Notre Dame, IN

PCI Convention, Palm Springs, California, October 17-20, 1999

Page 2: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

1998 PCI Daniel P. Jenny Research Fellowship

University of Notre Dame

Page 3: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

ELEVATION

wall panel

horizontaljoint

unbondedPT steel

spiralreinforcement

foundation

anchorage

Page 4: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

GAP OPENING BEHAVIOR

gap

Page 5: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

BASE PANEL

compression stresses

shearstresses

Page 6: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

CRACKING

1

2

2

3

3

4

5

5

3

Page 7: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

RESEARCH OBJECTIVES

• Develop analytical model

• Conduct parametric investigation

• Develop design approach

Page 8: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

FINITE ELEMENT MODEL

truss elements

contact elements

nonlinearplane stress elements

Page 9: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

ABAQUS MODEL

Page 10: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

GAP OPENING

Page 11: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

ABAQUS VERSUS DRAIN

base shear (kips)

0 0.5 1 1.5 2 2.5

500

1000

roof drift (%)

DRAIN

yielding state

gap openingstate ABAQUS

Page 12: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

ABAQUS VERSUS DRAIN

roof drift (%)

contact length / wall length

0 0.5 1 1.5 2 2.5

0.5

1.0

ABAQUS

DRAIN

Page 13: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

CLOSED FORM VERIFICATION (Savin 1961)(INFINITE PANEL)

ftx

T

C

Page 14: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

ABAQUS VERSUS CLOSED FORM SOLUTIONftx (ksi)

closed form (Savin 1961)ABAQUS

6.00 3.0

1.2

0.6

ho/lo

loho

Page 15: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

PARAMETRIC INVESTIGATION

• Wall length

• Initial concrete stress

• Opening size

Page 16: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

WALL LENGTH

10 feet x 16 feet

15 feet x 16 feet

20 feet x 16 feet

Page 17: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

INITIAL CONCRETE STRESSlp=20 feet CL

fci=1.48 ksi (high seismicity)

fci=0.67 ksi (medium seismicity)

fci=0.34 ksi (no seismicity)

Page 18: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

OPENING SIZE

lo

ho hp=16 feet

lp=20 feet

ho

2 feet (0.13 hp)

4 feet (0.25 hp)

6 feet (0.38 hp)

8 feet (0.50 hp)

lo 2 feet (0.10 lp)

4 feet (0.20 lp)

8 feet (0.40 lp)

6 feet (0.30 lp)

10 feet (0.50 lp)

Page 19: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

STAGES OF RESPONSE

• Gravity and post-tensioning only

• Gap opening

• PT steel yielding

• Concrete crushing

Page 20: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

UNDER GRAVITY AND POST-TENSIONING ONLY

Asf or Asc

Page 21: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

EFFECT OF fci

(lp=20 feet)Asf (in2)

0

1.0

2.0

0.5 1.0 1.5fci

ho/hp=0.125ho/hp=0.25ho/hp=0.375

lo/lp=0.3

lo

lp

hpho

Page 22: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

EFFECT OF fci

(lp=20 feet)Asf (in2)

0

1.0

2.0

0.5 1.0 1.5fci

lo/lp=0.1lo/lp=0.2

lo/lp=0.4lo/lp=0.3

ho/hp=0.25

lo

lp

hpho

Page 23: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

Asf (in2)

ho/hp

0 0.25 0.5

1.0

2.0lp=20 feetlp=15 feetlp=10 feet

EFFECT OF ho

(fci=0.68 ksi)

lo/lp=0.3lo

lp

hpho

Page 24: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

Asf (in2)

lo/lp

0 0.25 0.5

1.0

2.0lp=20 feetlp=15 feetlp=10 feet

EFFECT OF lo

(fci=0.68 ksi)

ho/hp=0.25

lo

lp

hpho

Page 25: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

EFFECT OF fci

(lp=20 feet)

0

10

20

30

Asc (in2/ft)

0.5 1.0 1.5fci

ho/hp=0.125ho/hp=0.25ho/hp=0.375

lo/lp=0.3

lo

lp

hpho

Page 26: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

EFFECT OF fci

(lp=20 feet)

0

10

20

30

Asc (in2/ft)

0.5 1.0 1.5fci

lo/lp=0.1lo/lp=0.2

lo/lp=0.4lo/lp=0.3 ho/hp=0.25

lo

lp

hpho

Page 27: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

EFFECT OF ho

(fci=0.68 ksi)

0.5ho/hp

0.25

Asc (in2/ft)

0

lp=20 feetlp=15 feetlp=10 feet

15

10

5

lo/lp=0.3

lo

lp

hpho

Page 28: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

Asc (in2/ft)

lo/lp

0.25 0.50

5

10

15

ho/hp=0.25lp=20 feetlp=15 feetlp=10 feet

EFFECT OF lo

(fci=0.68 ksi)

lo

lp

hpho

Page 29: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

DESIGN PREDICTION

T

C

C

Page 30: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

PREDICTED VERSUS ABAQUS(lp=20 feet)Asf (in2)

0.5 1.0 1.50

1.0

2.0

fci

predictedABAQUS

lo/lp=0.3ho/hp=0.25

lo

lp

hpho

Page 31: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

0 0.25 0.5

1.0

2.0Asf (in2)

ho/hp

lp=20 feet

PREDICTED VERSUS ABAQUS (fci=0.68 ksi)

lo/lp=0.3

predictedABAQUS

lo

lp

hpho

Page 32: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

0 0.25 0.5

1.0

2.0Asf (in2)

lo/lp

lp=20 feet

PREDICTED VERSUS ABAQUS (fci=0.68 ksi)

ho/hp=0.25

predictedABAQUS

lo

lp

hpho

Page 33: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

0

10

20

30

PREDICTED VERSUS ABAQUS (lp=20 feet)

predictedABAQUS

0.5 1.0 1.5fci

lo/lp=0.3ho/hp=0.25

Asc (in2/ft)

lo

lp

hpho

Page 34: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

Asc (in2/ft)

15

0 0.25 0.5

5

10

ho/hp

lp=20 feet

PREDICTED VERSUS ABAQUS (fci=0.68 ksi)

lo/lp=0.3

predictedABAQUS

lo

lp

hpho

Page 35: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

lo/lp

Asc (in2/ft)

0.25 0.50

5

10

15

lp=20 feet

PREDICTED VERSUS ABAQUS (fci=0.68 ksi)

ho/hp=0.25

predictedABAQUS

lo

lp

hpho

Page 36: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

0 2.0 4.0

ho/lo

1.0

lp=10 feet (fci=0.68 ksi)lp=15 feet (fci=0.44 ksi)lp=15 feet (fci=0.68 ksi)lp=20 feet (fci=0.68 ksi)

lp=20 feet (fci=1.48 ksi)lp=20 feet (fci=0.67 ksi)

lp=20 feet (fci=0.34 ksi)

1.5

Asf (predicted/ABAQUS)ALL CASES

0.5

Page 37: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

CONCLUSIONS

Analytical Model• ABAQUS model developed for walls with openings• ABAQUS results compare well with DRAIN-2DX results and closed form

results

Parametric Investigation• Gravity and post-tensioning loads only

• As fci increases, steel requirement increases significantly

• As ho increases, steel requirement decreases, especially for longer walls

• As lo increases, steel requirement increases, especially for shorter walls

Page 38: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

CONCLUSIONS

Design Approach

• Utilizes a strut-and-tie model

• Can be used to predict the ABAQUS results; and

• To design the reinforcement above the openings

– Asc to prevent cracking

– Asf to minimize crack widths

Page 39: DESIGN OF LARGE OPENINGS IN UNBONDED POST-TENSIONED PRECAST CONCRETE WALLS Michael G. Allen Yahya C. Kurama University of Notre Dame Notre Dame, IN PCI

REMAINING WORK

• Design for lateral loads

• Experimental verification (Lehigh Tests)