Near‐Source Ground Motion and its Effects on Flexible Buildings

Occurrence of large earthquakes close to cities in California is inevitable. The resulting ground shaking will subject buildings in the near‐source region to large, rapid displacement pulses which are not represented in design codes. The simulated M w 7.0 earthquake on a blind‐thrust fault used in this study produces peak ground displacement and velocity of 200 cm and 180 cm/sec, respectively. Over an area of several hundred square kilometers in the near‐source region, flexible frame and base‐isolated buildings would experience severe nonlinear behavior including the possibility of collapse at some locations. The susceptibility of welded connections to fracture significantly increases the collapse potential of steel‐frame buildings under strong ground motions of the type resulting from the M w 7.0 simulation. Because collapse of a building depends on many factors which are poorly understood, the results presented here regarding collapse should be interpreted carefully.