Transcript Slide 1
SEISMIC RESPONSE OF LOW ASPECT RATIO REINFORCED CONCRETE SHEAR WALLS Bismarck Luna
Ph.D. Candidate Civil, Structural and Environmental Engineering, University at Buffalo
• • • •
Acknowledgement
National Science Foundation Dr. Joy M. Pauschke, NEESR Program Director Project team members University at Buffalo Jonathan Rivera, Joshua Rocks, Dr. Caglar Goksu (ITU), Emma Lejeune (Cornell REU), Prof. Andrew Whittaker (PI) University of California, Berkeley Catherine Whyte, Prof. Bozidar Stojadinovic (Co-PI) University of Washington Joshua Pugh, Anna Birely, Prof. Laura Lowes (Co-PI) California Polytechnic State University, San Luis Obispo Prof. Abraham Lynn (Co-PI) LPCiminelli, Inc. MCEER (http://mceer.buffalo.edu/) 2 Quake Summit 2012, Boston, Massachusetts
Outline of presentation
• • • • • • • • • Goals Specimen details Test setup Instrumentation Global response Peak shear strength Lateral stiffness Strength degradation Future work Quake Summit 2012, Boston, Massachusetts 3
Goals
• • • • • • • Acquire robust information on the seismic behavior of low aspect ratio rectangular RC shear walls Provide simulation tools as needed Revise predictive equations for shear strength and stiffness Understand force transfer in walls at different levels of drift Develop macro-level hysteretic models Update fragility functions and damage states Response modification factors 4 Quake Summit 2012, Boston, Massachusetts
Specimen details
Web Wall h w /l w ρ l (%) SW1 0.94 0.67
SW2 1.0
SW3 SW4 0.54
0.67
0.33
SW5 SW6 SW7 SW8 SW9 SW10 SW11 SW12 0.33
0.54
1.0
0.67
0.33
1.5
1.5
1.5
0.67
0.33
ρ t (%) 0.67
1.0
0.67
0.33
1.0
0.67
0.33
1.5
0.67
0.33
0.67
0.33
Boundary Element ρ l ρ t (%) (%) 1.5
2.0
3600 7000 7800 4200 4300 3800 3800 3500 67 63 63 67 67 67 67 67 4300 4600 67 67 1.5 4800* 67* 2.0 5000* 67* 102 87 87 102 102 102 102 102 102 102 102* 102* Quake Summit 2012, Boston, Massachusetts SW9 SW12 5
Test setup
Test fixture setup Specimen SW2 Quake Summit 2012, Boston, Massachusetts 6
• In-plane string potentiometers and temposonics • Out-of-plane string potentiometers • Krypton system • Strain gages
Instrumentation
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Gigapan system
Instrumentation
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Global response
SW3 SW4 SW6 SW7 Quake Summit 2012, Boston, Massachusetts 9
Peak shear strength
800 600 400 200 0 -200 -400 -600 -800 -3 -2 -1 0 Drift Ratio (%) 1 SW3 2 3
Specimen
SW1 SW2
SW3
SW4 SW5 SW6 SW7 SW8 SW9
C1 Measured (kips)
253 563
468
226 726 571 317 623 633
C2 ACI 318 §21.9 (kips)
576 803
660
400 630 592 386 592 622
C2/C1
2.28
1.43
1.41
1.77
0.87
1.04
1.22
0.95
0.98
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Peak shear strength
1200 1000 800 600 400 200 0 1 2 3 4 5 6 7 Specimen (SW) number 8 9 ACI 318 Chapter 11 ACI 318 Chapter 21 Barda (1977) Wood (1990) Gulec (2009) Measured 11 Quake Summit 2012, Boston, Massachusetts
Lateral stiffness
500 400 300 200 100 0 0 0.5
1 Disp (in) SW3 1.5
2 12
Lateral stiffness
Specimen SW1 SW2
SW3
SW4 SW5 SW6 SW7 SW8 SW9 Measured initial stiffness (kips/in) 2400 3400
3900
3000 8900 10100 15800 3700 5020 Theoretical ‘uncracked’ (kips/in) 4886 19709
20805
15267 30527 28697 27931 14522 15488 500 400 300 200 100 0 0 ASCE 43-05 ‘cracked’ (kips/in) 2443 9855
10403
7634 15264 14349 13966 7261 7744 0.5
1 Disp (in) 1.5
Secant stiffness at peak resistance (kips/in) 172 693
344
322 1682 1719 1757 1369 1014 2 SW3 Col. 5 / Col. 4 0.07
0.07
0.03
0.04
0.11
0.12
0.13
0.19
0.13
13
SW8
Strength degradation
Specimen SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8 SW9 𝑉 2 𝑉 1 0.84
0.79
0.60
0.72
0.42
0.87
0.86
0.80
0.85
𝑉 3 𝑉 1 0.79
0.70
0.44
0.63
0.22
0.81
0.8
0.68
0.74
𝑉 4 𝑉 1 0.41
0.14
0.3
0.53
0.51
0.45
0.42
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Future work
• • • • • Testing of the remaining two specimens Data reduction Processing Krypton data Analysis of cracks and strain gage data Processing Gigapan images Quake Summit 2012, Boston, Massachusetts 15
THANK YOU
[email protected]
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