Bridge response to traveling seismic waves

This report describes an advanced methodology (BASSIN), for analyzing traveling seismic wave effects on the dynamic response of an arbitrarily-configured, elastic bridge system (comprised of a road deck, piers, abutments, backfill, etc.). A substructuring approach has been used to formulate BASSIN; in this, the bridge system is represented using a three dimensional finite element model, and the underlying soil is depicted using a boundary element approach based on elastic half-space theory. Seismic excitations are induced by plane body waves or Raleigh waves with arbitrary direction of incidence, wavelength, and amplitude. BASSIN allows for a fully deformable interface between the bridge system and the underlying soil, and incorporates a special modal truncation procedure to account for higher mode response characteristics.