Limit State Exceedance Probabilities of Building Performance under Earthquake Excitation Using Rupture-to-Rafters Simulations

Abstract

In this paper, the performance of two 18-story steel moment frame buildings (UBC 1982 and 1997 designs) in southern California under plausible San Andreas fault earthquakes in the next 30 years is quantified. The approach integrates rupture-to-rafters simulations into the PEER performance-based earthquake engineering (PBEE) framework. Using stochastic sources and computational seismic wave propagation, three-component ground motion histories at 636 sites in southern California are generated for 60 scenario earthquakes on the San Andreas fault. The ruptures, with moment magnitudes in the range of 6.0–8.0, are assumed to occur at five locations on the southern section of the fault. Two unilateral rupture propagation directions are considered. The 30-year probabilities of all plausible ruptures in this magnitude range and in that section of the fault, as forecast by the United States Geological Survey, are distributed among these 60 earthquakes based on proximity and moment release. The response of the two 18-story buildings hypothetically located at each of the 636 sites under three-component shaking from all 60 events is computed using 3-D nonlinear time-history analysis. Using these results, the probability of the structural response exceeding Immediate Occupancy (IO), Life-Safety (LS), and Collapse Prevention (CP) performance levels under San Andreas fault earthquakes over the next 30 years is evaluated.