Seismic behavior assessment for design of integral abutment bridges in Illinois

Integral abutment bridges (IABs) minimize deterioration and degradation of the abutment seats and bearings due to water, dirt, and deicing chemicals by eliminating bearings and expansion joints. Although the continuity between superstructure and abutments in an IAB is beneficial for reducing maintenance costs, it leads to more complex behavior under strength and service loading (temperature and traffic) and extreme loading (earthquake). The coupling of superstructure and substructure behavior necessitates system-level analysis of IABs. Prior seismic IAB studies have typically investigated the behavior of individual IAB components, however a gap of knowledge has developed due to the lack of studies and investigation about the behavior of all IAB components and their interactions with each other in a single analysis model. This study uses nonlinear static and dynamic analyses to investigate and assess the seismic behavior of IABs typical to the state of Illinois. The analyses aim to bridge the gap of knowledge by evaluating IABs as a whole and utilizing the results to indicate potential vulnerabilities in the design and construction of IABs in Illinois during design-level and larger seismic events, which could not be identified by component-level IAB analyses alone.