PRECAST CONCRETE COUPLED PRECAST CONCRETE COUPLED WALL SYSTEMSWALL SYSTEMS

Brad Weldon

Yahya C. (Gino) Kurama

University of Notre Dame

PCI Daniel P. Jenny Research Fellowship

PCI Committee Days

April 24, 2004

REINFORCED CONCRETE COUPLED WALLS

LMw1 Mw2

C=TT

mechanisms of shear resistance in reinforced concrete coupling beams

CD Mw1+Mw2+TL

TL

Coupling Degree

Paulay and Priestley 1991 wall beam wall

beam

PT tendon

connectionregion

PTanchor

angle wall region

confinementconcrete wall

precast beam

PT tendon

beam

PRECAST CONCRETE COUPLING BEAMS

PT duct

confined concrete

DEFORMED SHAPE AND COUPLING FORCES

PP

Vcoupling

Vcoupling

dbz

lb

contactregion

gapopening

reference line

beam

Vcoupling Pz

lb

OBJECTIVES

• Develop new system based on experimental and analytical studies

• Develop seismic design/analysis guidelines and tools, and recommendations for application

• Steel Coupling Beams Experimental program Analytical model and verification

• Precast Coupling Beams Advantages Parametric studies (DRAIN-2DX) Design approach

OUTLINE

STEEL BEAM TESTS

Objectives• Investigate

M- behavior• Verify analy. models• Verify design tools

and procedures

• Eleven half-scale coupled wall subassemblages (angle, beam, post-tensioning properties)

W10x68PT strand

L4x8x5/8

ap=140 mm2

(0.217 in2)

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

strong floor

fpi=0.6fpu

Elevation View (half-scale)

load block

test wall regionand reaction fixture

TEST SET-UP

beambeamwallwallregionregion

loading blockloading block

reaction reaction blockblock

actuatorsactuators

ANGLE FRACTURE

Beam rotation = 9%Beam rotation = 9%

Test 2Test 2

Test 5Test 5

Test 5Test 5

CYCLIC BEHAVIOR OF STEEL COUPLING BEAM applied shear force, kips (kN)

beam chord rotation, %-10 0 10

0

60

-60

measured(267)

(-267)

ANALYTICAL WALL MODEL (DRAIN-2DX)

beam chord rotation, %-10 0 10

0

60

-60

applied shear force, kips (kN)

predicted measured(267)

(-267)

VERIFICATION OF MODEL

POST-TENSIONED COUPLED WALLS

• Unbonded post-tensioning is a promising and feasible method to couple concrete walls (up to 60-65 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

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

PARAMETRIC STUDY DRAIN-2DX(Half-Scale Subassemblages)

Varied Parameters:

• beam depth

• amount of PT

• angle size

• gage length

• aspect ratio

Beam Depth (in)

Angle PT Strands

Gage Length (in)

Aspect Ratio

14 L8x4x1/2 3 3 3.21

14 L8x4x1/2 3 5 3.21

14 L8x4x1/2 4 3 3.21

14 L8x4x1/2 4 5 3.21

14 L8x4x5/8 3 3 3.21

14 L8x4x5/8 4 5 3.21

18 L8x4x1/2 3 3 2.5

18 L8x4x1/2 3 5 2.5

18 L8x4x1/2 4 3 2.5

18 L8x4x1/2 4 5 2.5

18 L8x4x5/8 3 3 2.5

18 L8x4x5/8 4 5 2.5

TEST SPECIMENS(Half-Scale)

Beam Depth (in)

AnglePT

Strands

Gage Length

(in)

Aspect Ratio

Parameter

14 L8x4x1/2 3 5 3.21Baseline

Test

14 L8x4x1/2 4 5 3.21 ap

14 L8x4x5/8 4 5 3.21 Angle

18 L8x4x1/2 4 5 2.5Depth,

aspect ratio

TEST SPECIMEN CROSS-SECTIONS(Half-Scale)

7”

7”

7”

7”

14”

14”

14”

18”

L8x4x1/2

L8x4x1/2

L8x4x1/2

L8x4x5/8

DRAIN-2DX SPECIMEN BEHAVIOR a

pp

lied

sh

ear

forc

e,

kip

s (

kN

)

ap

pli

ed s

hea

r fo

rce,

ki

ps

(k

N)

app

lied

sh

ear

forc

e,

kip

s (

kN

)

app

lied

sh

ear

forc

e,

kip

s (

kN

)

-8.0 0 8.0 -80

0

80D = 18” L8x4x5/8 PT = 4

(356)

(-356)

-60

60(267)

(-267) -60

60(267)

(-267)

D = 14” L8x4x1/2 PT = 3

D = 14” L8x4x5/8 PT = 4

D = 14” L8x4x1/2 PT = 4

-80

80(356)

(-356)

beam chord rotation, (%)

-8.0 0 8.0 beam chord rotation, (%)

-8.0 0 8.0 beam chord rotation, (%)

-8.0 0 8.0 beam chord rotation, (%)

FINITE ELEMENT MODEL (ABAQUS)

DRAIN-2DX VERSUS ABAQUS

beam shear, kips (kN) contact depth/depth

beam rotation, % beam rotation, %

300(1335)

0 7 0 7

DRAIN-2DXABAQUS

DRAIN-2DXABAQUS

1

MINIMUM PRINCIPAL STRESSES

MAXIMUM PRINCIPAL STRESSES

BEAM DESIGN

confined concrete

PT duct

transverse reinforcement

longitudinal reinforcement

thru ducts for angle connection

BEAM DESIGN

PT duct

confined concrete

longitudinal reinforcement

transverse reinforcement

beam side viewbeam end view

BEAM TO WALL CONNECTION

wire mesh

PT strand

L8x4x1/2

thru bolt

confined concrete

grout

CURRENT STATUS

• Finalizing design• Laboratory set-up• Begin testing this summer

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