Parallel simulation of structural performance in earthquakes

This study examines, by computational simulation, the spatial and temporal distribution of the earthquake ground motion and structural response near a fault. An idealized 20 km by 20 km region is modeled as a layer on an elastic halfspace with dense spatial sampling for frequencies up to 5 Hz. Two scenario events are considered, a strike-slip fault and a thrust fault. For the strike-slip fault event, the fault normal component exhibits a strong forward directivity effect with a pulse-type motion. For the thrust fault event the greatest concentration of ground motion occurs in the up-dip direction.; Inelastic single-degree-of-freedom models of structural systems are used to examine the spatial distribution of structural response to the simulated ground motion. The spatial variability of structural response is strongly related to the distribution of ground motion. For the thrust-fault event, the largest displacements occur in the up-dip direction; for the strike-slip fault event, the largest displacements occur in the fault normal direction in the forward directivity zone. The spatial distributions of the ratios of inelastic and elastic structural displacement show that the equal-displacement rule is valid, within a 20 percent tolerance, near the fault. The response of SDF systems with design strength provided by the 1997 Uniform Building Code indicates that for structures with vibration periods less than 1 sec, the ductility demands may greatly exceed a value of four in the forward directivity zone.; The responses of realistic steel moment frame buildings were examined for the simulated ground motions. Most severe damage occurs in the forward directivity zone in fault-normal direction and near the epicenter in fault-parallel direction. For 9- and 20-story buildings in the fault-normal direction in forward directivity zone have large story drift in lower and higher floors, which indicates an undesirable soft story mechanism. The near-fault ground motions have significant effects on the distribution of story deformation over the height of the building. A Consistent Performance Design procedure is presented to determine the seismic design base shear coefficient of multi-story building structures such that its maximum story drift is limited regardless of its location in the region.