Seismic Response of a Typical Highway Bridge in Liquefiable Soil

For reliable estimation of bridge performance, especially when subjected to liquefaction and lateral spreading, appropriate modeling of soil-pile-structure interaction and understanding of the global bridge behavior are essential. In practice, soil and foundation systems are often approximated using very simple foundation springs or unrealistic lateral spreading mechanisms that may not represent all important aspects of the global system behavior. In this context, a detailed bridge model of a typical highway overpass bridge in liquefiable soils was developed with an emphasis on accurate characterization of the structural and soil behavior, including various soil-pile-structure (SPSI) modeling strategies for several components in the bridge system, such as piles, pile caps, and abutment structures. Using this model, the global behavior of the bridge system is more readily understood by capturing realistic force boundary conditions at the bridge pier bases and bridge deck ends. In addition, important bridge damage mechanisms are identified.