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 (M w 15 km and M w 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 M w 7.5 time histories analysis for two depths to demonstrate differences in difference non-linear programs

Target Spectrum (A&S strike-slip, rock) M w =6.5 r=15 kmM w =7.5 r=5 km

Shear Wave Velocity Profile La Clenega Site – Simplified CJR Model

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

Deep Profile – 500 ft M7.5 Ground Surface Response

Deep Profile – 500 ft M6.5 Ground Surface Response

Deep Profile – 500 ft Ground Surface Response

Med. Deep Profile – 300 ft Ground Surface Response

Shallow Profile – 100 ft Ground Surface Response

Deep Profile – 500 ft Average Spectral Ratio

Med. Deep Profile – 300 ft Average Spectral Ratio

Shallow Profile – 100 ft Average Spectral Ratio