NGA Site Response Study Joseph Sun, Tom Shantz, Zhi-Liang Wang.
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NGA Site Response Study Joseph Sun, Tom Shantz, Zhi- Liang Wang
Transcript of NGA Site Response Study Joseph Sun, Tom Shantz, Zhi-Liang Wang.
NGA Site Response Study
Joseph Sun, Tom Shantz, Zhi-Liang Wang
Project Objectives
• Compare RVT based site response response calculation versus time history approach
• Compare RVT based amp factors (RASCALS) with time history based (SHAKE) amp factors
• Compare amp factor differences between equivalent-linear procedure (RASCALS and SHAKE) and non-linear procedures (D-MOD2 and SUMDES)
Basis of Comparison:• Two shaking levels (Mw 6.5 @ 15 km and Mw 7.5@ 5
km)• Three profile depths (100, 300, and 500 ft)• 30 spectrum compatible ground motions were used for
each shaking level. • Results from one RVT run from RASCALS is
compared with the average of 30 SHAKE run • Non-linear analysis scope reduced to two Mw7.5 time
histories analysis for two depths to demonstrate differences in difference non-linear programs
0.01 0.1 1 10Pe rio d (se c)
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M w 7.5, Input M otion R esponse
A verage
0 20 40 60 80Timesecs-0.6
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noitareleccAg
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0 25 50 75 100 125 150Timesecs-0.4
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M w 6.5, Input M otion R esponse A verage
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M w 6 .5 , A verage Input M otion R esponse
SH AKE
R ASC AL
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M w 7 .5 , A verage Input M otion R esponse
SH A KE
R A S C A L
Target Spectrum (A&S strike-slip, rock)
Mw=6.5 r=15 kmMw=7.5 r=5 km
Shear Wave Velocity ProfileLa Clenega Site – Simplified CJR Model
0 1000 2000 3000
Vs (ft/sec)
500
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0D
ept
h (f
t)
0.0001 0.001 0.01 0.1
Sand
Clay
Sand & Clay
Non-Linear Properties
• Based on SHAKE91• Extend to 10% strain• 2 Curves only – simple• Decoupled modulus and damping• Non-linear models should base on matching modulus reduction curves. Damping may be different
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M w 7.5, D eep P rofile - 500 ftSH AKE - G round Surface R esponse
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Deep Profile – 500 ft M7.5 Ground Surface Response
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M w 6.5, D eep P rofile - 500 ftSH AKE - G round Surface R esponse
A verage
Deep Profile – 500 ftM6.5 Ground Surface Response
Deep Profile – 500 ftGround Surface Response
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M w 6.5, R= 15 kmSH AKE, m eanRASC ALSH AKE, 84th PercentileSH AKE, 16th Percentile
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M w 7.5, R= 5 kmSH AKE, m eanRASC ALSH AKE, 84th PercentileSH AKE, 16th Percentile
Med. Deep Profile – 300 ftGround Surface Response
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M w 6.5 , R =15 kmSH AKE, m eanRASC ALSH AKE, 84th PercentileSH AKE, 16th Percentile
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M w 7.5, R= 5 kmSH AKE, m eanRASC ALSH AKE, 84th PercentileSH AKE, 16th Percentile
Shallow Profile – 100 ftGround Surface Response
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M w 6.5, R= 15 kmSH AKE, m eanRASC ALSH AKE, 84th PercentileSH AKE, 16th Percentile
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M w 7.5, R= 5 kmSH AKE, m eanRASC ALSH AKE, 84th PercentileSH AKE, 16th Percentile
Deep Profile – 500 ftAverage Spectral Ratio
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M w 6.5, R= 15 kmSH AKERASC AL
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M w 7.5, R= 5 kmSH AKERASC AL
Med. Deep Profile – 300 ftAverage Spectral Ratio
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M w 6.5, R= 15 kmSH AKERASC AL
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Shallow Profile – 100 ftAverage Spectral Ratio
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M w 7.5, R= 5 kmSH AKERASC AL
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M w 6.5, R= 15 kmSH AKERASC AL
