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

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

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

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

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

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

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

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

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

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

ANALYTICAL WALL MODEL (DRAIN-2DX)

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

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) 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

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

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

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, (%)

FINITE ELEMENT MODEL (ABAQUS)

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, %

MINIMUM PRINCIPAL STRESSES

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.

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

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

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

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