Centrifuge Experimentation of Building Performance on Liquefied Ground

Centrifuge experiments were performed at the NEES@Davis Geotechnical Centrifuge Facility to develop insight into the seismic performance of structures at sites undergoing liquefaction. Three structural models, each representing simple structures founded on shallow rigid mats, were placed on each soil model. The soil profile contained a shallow layer of potentially liquefiable sand to investigate the effects of foundation width and contact pressure on building performance at sites with soil liquefaction. The base of the model container was excited by a sequence of three horizontal shakings, simulating increasing intensities of the Port Island down-hole recordings from the 1995 Kobe Earthquake. Two experiments are described wherein the liquefiable saturated, loose Nevada Sand layer varied in thickness from 3 m to 6 m (prototype scale). A summary of building and free-field movements observed in each experiment is presented with a comparison of the centrifuge results with actual building settlements observed in previous earthquakes. The results from these experiments provide valuable insight, because engineers generally apply methods developed for estimating free-field seismic settlement of clean sand deposits in evaluation of potential building movements at sites prone to liquefaction.