Numerical Simulations and Field Monitoring of Integral Abutment Bridges

Integral abutment bridges (IABs) can result in decreased construction and maintenance costs, but certain aspects of their structural behavior are still not well understood. Most IAB research has related to the behavior of their substructures, with the limit states considered by entities such as the Illinois Department of Transportation (IDOT) largely based on substructure considerations. It is expected that integral abutment construction also affects superstructure behavior and demands, in addition to superstructure properties directly influencing substructure behavior. As a result, IDOT and the Illinois Tollway have sponsored a research project, investigating IAB behavior as it relates to bridge superstructures. The overall goal of the research is to improve design and construction provisions and details for IABs, so that actual in-service demands are more rigorously considered and IABs are efficiently used. The research project is employing a detailed suite of parametric numerical simulations, complemented by thorough field monitoring of two IABs located in northern Illinois. This paper presents findings from: 1) a subset of the numerical simulations, where effects of parameters such as abutment skew, overall bridge length, intermediate span length, and bridge width are examined; and 2) preliminary field data from the monitored bridges for the first complete summer-to-winter temperature cycle. An initial assessment of the key response quantities of longitudinal bridge displacement, thermally-induced elastic stresses in the superstructure, and inelastic pile strains are presented.