Publisher's Synopsis
The current AASHTO specifications for seismic design mandate site-specific evaluation of the earthquake design ground motion (i.e., the acceleration response spectrum) for ground conditions termed Site Class F. In the AASHTO specifications, Site Class F soils include soft clay sites. These AASHTO specifications also allow discretionary site-specific analyses for other ground conditions and a reduction in mapped design ground motions of as much as 33% if justified by a site-specific ground motion analysis. Some state departments of transportation (DOTs) are taking advantage of this site response reduction provision, particularly in cases where pore pressure generation could lead to soil liquefaction-.
