Soil Property Determination for a Seismic Study

Static and dynamic soil property data were needed for input into the seismic retrofit design for the I-155 Mississippi River crossing located near the center of the New Madrid Seismic Zone. Soils consisted of recent river alluvium underlain by very dense soils of the Mississippi embayment. The field investigation consisted of conventional borings, downhole geophysical tests to measure shear wave velocity, and seismic piezo-cone soundings. SPT energy measurements were made at one boring to confirm hammer energy for liquefaction evaluation. This paper summarizes the data and provides site specific correlation of shear wave velocity vs. N-value from the seismic cone and downhole geophysical tests; measured SPT energy value; and estimates of static and dynamic soil properties