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Partially Post-Tensioned Precast Concrete Walls

Partially Post-Tensioned Precast Concrete Walls. Yahya C. (Gino) Kurama Assistant Professor University of Notre Dame Notre Dame, Indiana, USA. American Concrete Institute Spring 2003 Convention Vancouver, Canada April 2, 2003. POST-TENSIONED PRECAST CONCRETE WALL. anchorage. wall panel.

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Partially Post-Tensioned Precast Concrete Walls

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  1. Partially Post-TensionedPrecast Concrete Walls Yahya C. (Gino) Kurama Assistant Professor University of Notre Dame Notre Dame, Indiana, USA American Concrete Institute Spring 2003 Convention Vancouver, Canada April 2, 2003

  2. POST-TENSIONED PRECAST CONCRETE WALL anchorage wall panel horizontal joint unbonded PT bars spiral reinforcement foundation spiral bonded unbonded reinforcement wire mesh PT bar precast wall with full PT

  3. BEHAVIOR UNDER LATERAL LOADS gap opening

  4. HYSTERETIC BEHAVIOR base shear, kips (kN) 800 (3558) roof drift, % 1 -2 2 -1 0 -800 (-3558)

  5. VERTICALLY JOINTED WALLS friction or metallic-yield damper Priestley et al. Perez et al. Kurama Pall et al.

  6. DISPLACED SHAPE

  7. WALLS WITH PARTIAL POST-TENSIONING unbonded PT bar bonded mild bar unbonded bonded mild bar PT bar precast wall with partial PT

  8. mild steel yielding ENERGY DISSIPATION

  9. PARTIALLY POST-TENSIONED PRECAST FRAME column fiber reinforced grout trough mild steel bar beam PT tendon beam-to-column joint Cheok et al. Priestley et al. Stanton et al. Nakaki et al.

  10. OBJECTIVES • Investigate precast wall systems with PT steel and mild steel • Develop seismic design approach • Evaluate seismic response

  11. OUTLINE • Prototype walls and expected behavior • Seismic design approach and evaluation • Summary and conclusions

  12. PROTOTYPE WALLS • Four fully post-tensioned walls • Four walls with only mild steel (emulative walls) • Four partially post-tensioned walls

  13. PLAN LAYOUT OF PROTOTYPE BUILDINGS 8 x 24 ft = 192 ft (58.5 m) hollow- lateral load gravity load core frame frame panels 40 + 30 + 40 = 110 ft (33.5 m) wall inverted column L-beam T-beam N 4 story building, high seismicity 6 story building, high seismicity 10 story building, high seismicity 6 story building, medium seismicity

  14. FULLY POST-TENSIONED WALLS 133 ft (41 ft) 81 ft 81 ft (25 ft) (25 ft) 55 ft (17 ft) 26 ft (8 m) 20 ft (6 m) 20 ft (6 m) 20 ft (6 m) 4 story high seismicity 6 story high seismicity 10 story high seismicity 6 story medium seismicity

  15. FULLY POST-TENSIONED WALLS C C L L #3 spirals #3 spirals Ap=1.49in2 (961mm2) Ap=1.49in2 (961mm2) fpi=0.60-0.65fpu rsp=7.3% fpi=0.60-0.65fpu rsp=7.3% 12in. 12in. (305mm) (305mm) 10 ft (3 m) 10 ft (3 m) Wall PH4 Wall PH6 C C L L #3 spirals #3 spirals Ap=1.49in2 (961mm2) Ap=1.49in2 (961mm2) fpi=0.60-0.65fpu rsp=7.3% fpi=0.625fpu rsp=1.8% 12in. 12in. (305mm) (305mm) 13 ft (4 m) 10 ft (3 m) Wall PH10 Wall PM6

  16. EMULATIVE WALLS No. 8 bars No. 5 bars No. 8 bars No. 5 bars 16 pairs 5 pairs 15 pairs 5 pairs C C L L @ 18 in. @ 2.5 in. @ 2.25 in. @ 18 in. (@ 57 mm) (@ 457 mm) (@ 63 mm) (@ 457 mm) 12in. 12in. (305mm) (305mm) 10 ft (3 m) 10 ft (3 m) Wall EH4 Wall EH6 No. 6 bars No. 5 bars No. 8 bars No. 5 bars 7 pairs 5 pairs 20 pairs 6 pairs C C L L @ 5.25 in. @ 18 in. @ 2.25 in. @ 18 in. (@ 57 mm) (@ 457 mm) (@ 133 mm) (@ 457 mm) 12in. 12in. (305mm) (305mm) 10 ft (3 m) 13 ft (4 m) Wall EM6 Wall EH10

  17. PARTIALLY POST-TENSIONED WALLS No. 5 bars No. 5 bars No. 8 bars No. 5 bars C 7 pairs 5 pairs C 7 pairs 5 pairs L L @ 5.5 in. @ 18 in. @ 5.5 in. @ 18 in. (@ 140 mm) (@ 457 mm) (@ 140 mm) (@ 457 mm) 12in. 12in. (305mm) (305mm) 10 ft (3 m) 10 ft (3 m) Wall HH6-25 Wall HH6-50 No. 8 bars No. 5 bars No. 5 bars 11 pairs 5 pairs C 8 pairs C L L @ 3.5 in. @ 18 in. @ 17 in. (@ 89 mm) (@ 457 mm) (@ 432 mm) 12in. 12in. (305mm) (305mm) 10 ft (3 m) 10 ft (3 m) Wall HH6-75 Wall HM6-50

  18. ANALYTICAL WALL MODEL stress, ksi (MPa) 100 (690) truss element 0 MILD STEEL -100 (690) -0.08 0 0.08 fiber element strain stress, ksi (MPa) stress, ksi (MPa) 7 (48) 160 (1103) 120 (827) kinematic constraint strain 0 0 0.006 0.0351 strain PT STEEL CONCRETE

  19. WALL BEHAVIOR UNDER MONOTONIC LOADS base shear, kips (kN) base shear, kips (kN) 1000 1500 (4448) (6672) Wall PH6 Wall HH6-25 Wall HH6-50 Wall PH4 Wall HH6-75 Wall EH4 Wall EH6 0 3 0 3 roof drift, % roof drift, % base shear, kips (kN) base shear, kips (kN) 1000 500 (4448) (2224) Wall PM6 Wall PH10 Wall HM6-50 Wall EH10 Wall EM6 0 0 3 2 roof drift, % roof drift, %

  20. Wall HH6-25 Wall HH6-50 SIX STORY WALLS IN HIGH SEISMICITY base shear, kips (kN) base shear, kips (kN) base shear, kips (kN) 1000 Wall PH6 (4448) 0 (-4448) -1000 0 3 0 3 0 3 -3 -3 -3 roof drift, % roof drift, % roof drift, % base shear, kips (kN) base shear, kips (kN) 1000 1000 Wall EH6 Wall HH6-75 (4448) (4448) 0 0 (-4448) (-4448) -1000 -1000 0 3 3 0 -3 -3 roof drift, % roof drift, %

  21. NORMALIZED INELASTIC ENERGY DISSIPATION base shear, kips (kN) 1000 (4448) ksec Dh -Dc Dh 0 = dh -Dc Ue Ue (-4448) -1000 -3 0 3 roof drift, %

  22. NORMALIZED INELASTIC ENERGY DISSIPATION (dh = Dh / Ue) (dh = Dh / Ue) 2 2 Wall PH6 Wall PH4 Wall HH6-25 Wall EH4 Wall HH6-50 1.5 1.5 Wall HH6-75 Wall EH6 1 1 0.5 0.5 0 0 3 3 cycle roof drift, % cycle roof drift, % (dh = Dh / Ue) (dh = Dh / Ue) 2 2 Wall PH10 Wall PM6 Wall EH10 Wall HM6-50 1.5 1.5 Wall EM6 1 1 0.5 0.5 0 0 2 3 cycle roof drift, % cycle roof drift, %

  23. DYNAMIC RESPONSE roof drift, % roof drift, % 2.5 2.5 NOSY PH6 PH4 HH6-25 EH4 PGA=0.97g 0 0 HH6-50 NOSY HH6-75 EH6 PGA=0.97g -2.5 -2.5 0 15 0 15 time, seconds time, seconds roof drift, % roof drift, % 2.5 1.5 PH10 NOSY EH10 PGA=0.39g 0 0 PM6 HM6-50 NOSY EM6 PGA=0.97g -1.5 -2.5 0 15 0 15 time, seconds time, seconds

  24. REDUCTION IN MAXIMUM ROOF DRIFT normalized maximum roof drift 1.0 0.8 0.6 0.4 PH6 HH6-25 HH6-50 HH6-75 EH6 0.2 average 0 0 0.2 0.4 0.6 0.8 1 normalized mild steel ratio

  25. REDUCTION IN NUMBER OF DRIFT PEAKS average number of drift peaks average number of drift peaks 8 8 WALL PH6 WALL PH4 WALL HH6-25 WALL EH4 6 6 WALL HH6-50 WALL HH6-75 4 4 WALL EH6 2 2 0 0 0.5 1 0.5 1 normalized amplitude of drift peak normalized amplitude of drift peak average number of drift peaks average number of drift peaks 8 8 WALL PH10 WALL PM6 6 6 WALL EH10 WALL HM6-50 WALL EM6 4 4 2 2 0 0 0.5 1 0.5 1 normalized amplitude of drift peak normalized amplitude of drift peak

  26. OUTLINE • Prototype walls • Expected behavior • Seismic design approach and evaluation • Summary and conclusions

  27. roof drift, % 1.5 total first mode 0 Wall HW1 SAC LA25, PGA=0.87g -1.5 0 4 8 12 16 time, seconds FIRST MODE REPRESENTATION

  28. SDOF REPRESENTATION MDOF MODEL SDOF MODEL base shear, kips (kN) base shear, kips (kN) 2000 2000 (8896) (8896) 0 0 (8896) (8896) -2000 -2000 -3 0 3 -3 0 3 roof drift, % roof drift, % F akbe F F akbe [(1+br)Fbe,Dbe] (brFbe,Dbe) (Fbe,Dbe) D D D = + kbe (1+bs)kbe bskbe Bilinear-Elastic/ Bilinear-Elastic (BE) Elasto-Plastic (EP) Elasto-Plastic (BP)

  29. SAC GROUND MOTIONS pseudo-acceleration, g 4 Los Ang., SD soil, survival-level (SAC LA21-40) AVG spectrum 2 5% damping 0 0.5 1 1.5 2 2.5 3 3.5 period, seconds

  30. SDOF/MDOF PEAK DISPLACEMENT SDOF/MDOF maximum displacement ratio 1.2 1.0 mean 0.8 0.6 0.4 Wall HW1 SAC LA21- 40 0.2 0 50 100 (381) 150 maximum incremental velocity, in/sec (cm/sec)

  31. DUCTILITY DEMAND F F F akbe akbe [(1+br)Fbe,Dbe] (brFbe,Dbe) (Fbe,Dbe) D D D + = kbe (1+bs)kbe bskbe Bilinear-Elastic/ Bilinear-Elastic (BE) Elasto-Plastic (EP) Elasto-Plastic (BP) • bs = br = 1/4, 1/3, 1/2 • a = 0.02, 0.10 • Moderate and High Seismicity • Design-Level and Survival-Level • Stiff Soil and Medium Soil Profiles R=[c(m-1)+1]1/c Tab c= + Ta+1 T (Nassar & Krawinkler, 1991) (Farrow and Kurama, 2001)

  32. DUCTILITY DEMAND SPECTRA (Farrow and Kurama, 2001) br = bs = 1/3, a=0.10, High Seismicity, Stiff (Sd) Soil, R=1, 2, 4, 6, 8 (thin thick) Design EQ (SAC): a=3.83, b=0.87 Survival EQ (SAC): a=1.08, b=0.89 ductility demand, m ductility demand, m 14 14 BP, mean regression 0 0 3.5 3.5 period, seconds period, seconds Survival EQ (SAC): BP versus EP Survival EQ (SAC): BP versus BE ductility demand, m ductility demand, m 14 14 BP, mean EP, mean BE, mean 0 0 3.5 3.5 period, seconds period, seconds

  33. NONLINEAR DEMAND SPECTRA demand acceleration, g demand acceleration, g 1.5 1.5 T = 0.5 sec. T = 1.5 sec. m=1 m=1 a = -0.71 a = -0.71 b = 0.94 b = 0.94 1 1 (linear-elastic) (linear-elastic) 2 a = 2.3 2 1.5 1.5 T = 0.5 sec. T = 1.5 sec. m = 1 m = 1 a = 2.3 demand b = 1.3 b = 1.3 spectrum 1 1 2 2 a a S (g) S (g) B 4 D 4 0.5 0.5 C 8 8 E F capacity curve 4 0 0 20 40 60 80 100 20 40 60 80 100 S (cm) S (cm) d d (a) 1.5 1.5 T = 0.5 sec. T = 1.5 sec. m = 1 m = 1 0.5 a = -0.71 a = -0.71 0.5 b = 0.94 b = 0.94 1 1 A 4 2 2 a a S (g) S (g) B 4 D 0.5 0.5 4 C 8 8 E F 0 0 20 40 60 80 100 20 40 60 80 100 S (cm) S (cm) d d 8 (b) 8 0 0 (39) 100 (39) 100 demand displacement, cm (in.) demand displacement, cm (in.)

  34. DESIGN OBJECTIVES – SURVIVAL LEVEL base shear immediate occupancy (Dt=1.19%) collapse prevention (Dt=2.17%) WALL WH1 WALL WH2 roof drift

  35. WALLS HW1 AND HW2 No. 10 bars No. 5 bars C L 8 pairs 7 pairs @ 2.5 in. @ 18 in. (@ 63 mm) (@ 457 mm) 12in. (305mm) 11 ft (3.35 m) Wall WH1 No. 10 bars No. 5 bars C L 7 pairs 6 pairs @ 2.5 in. @ 18 in. (@ 63 mm) (@ 457 mm) 12in. (305mm) 10 ft (3 m) Wall WH2

  36. WALL HW1 maximum roof drift, % 3 2 Dt=1.19% 1 Dmean=1.13% 0 50 100 (381) 150 maximum incremental velocity, in/sec (cm/sec)

  37. WALL WH2 maximum roof drift, % 3.5 3 2.5 Dt=2.17% 2 Dmean=1.85% 1.5 1 0.5 0 50 100 (381) 150 maximum incremental velocity, in/sec (cm/sec)

  38. CONCLUSIONS • 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

  39. National Science Foundation CAREER-Program CMS 98-74872Program DirectorsDr. S. C. LiuDr. S. MaCabe

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