Evaluation of damage induced by lateral spread to roadways and bridges in Salt Lake County

Many areas within Salt Lake County, Utah are susceptible to liquefaction-induced ground failure resulting from a moderate to large, nearby seismic event. This susceptibility, in combination with the general terrain of the county, is expected to produce liquefaction-induced lateral spread ground deformation in many locations during such an event. Although lateral spread deformation is generally not life threatening, it can be very damaging to transportation infrastructure, especially bridges at river crossings. This type of damage from prior earthquakes has been very costly, both in terms of required repairs and the interruption it causes to traffic and the corresponding economic losses. This thesis develops a relatively simple methodology to estimate potential damage caused by lateral spread ground deformation to roadways and bridges located in Salt Lake County, Utah. This is done using mapped estimates of lateral spread displacement in conjunction with recently published lateral spread fragility curves. Such curves can be used to predict the damage states (i.e., condition) based on the estimates of lateral spread for mapped hazard zones. The results of this study, when used in conjunction with traffic modeling methods, will be useful to public officials and planners to prepare for the impacts of future seismic events along the Wasatch Fault in the Salt Lake Valley, Utah.