Abstract

In order to mitigate hazards and losses due to earthquakes, seismic design methodologies have been developed and implemented in design practice in many regions since the early twentieth century, often in the form of codes and standards. Most of these methodologies are based on a force-balance approach, in which structures are designed to resist a prescribed level of seismic force specified as a fraction of gravity. These methodologies have contributed to the acceptable seismic performance of port structures, particularly when the earthquake motions are more or less within the prescribed design level. Earthquake disasters, however, have continued to occur. These disasters are caused either by strong earthquake motions, often in the near field of seismic source areas, or by moderate earthquake motions in the regions where the damage due to ground failures has not been anticipated or considered in the seismic design.