Spatial Correlation Study of Strong Motion Array Data with Application to Lifeline Earthquake Engineering

摘要

Seismic design of structures with long dimensions located at the ground surface suchas bridges, pipelines, are usually controlled by strains and differential movements causedby body and surface waves generated by earthquakes. Based on the observed strong motionarray data, in particular the SMART-l array, a theoretical model is developed to estimatethe ground strains and differential movements.· With the use of conversion factors bywhich structural strains are derived from ground strains, methods for assessing thepotential damage and safety of a lifeline system under strong ground shaking during anearthquake are studied.A cross-spectrum model for surface waves is developed based on the SMART-l data.Numerical evaluation of parameters shows the attenuation is less important than the lossof coherence as waves propagate from the source to the. site. The dynamic response(deterministic as well as stochastic) of structures subject to spatial seismic waves isalso studied. The contribution of both in-phase and out-of-phase input motions to theresponse of an extended structure (such as a lifeline) is calculated. The sensitivity oflifeline longitudinal response to change in epicenter direction was also examined. Theroot-mean-square response is evaluated for the purpose of reliability assessment.