Deep foundations; seismic foundation behavior; soil property characterization; liquefaction. Past chairman of the Soil Properties Committee of ASCE; presented S-O-A paper on "Seismic Bridge Pile Foundation Behavior" at the Federal Highway Administration (FHWA) International conference on Deep Foundations; ongoing pile foundation research for Caltrans; liquefaction research for the Army Corps of Engineers; instructor for National Highway Institute's Soils Module