Numerical analysis method for long-term behavior of integral abutment bridges

Many engineering uncertainties exist in the prediction of integral abutment bridge (IAB) long-term behavior. This paper reports on the development of numerical modeling methodologies formulated on the basis of an extensive field monitoring program and results obtained from four IABs on I-99 in central Pennsylvania. The proposed numerical modeling methodologies allow long-term bridge response prediction, recognizing that an IAB has significant time-dependent response changes as a result of irreversible soil-structure interaction and time-dependent effects of the superstructure in the case of prestressed concrete girders. Both measured and numerical responses indicate that soil-structure interaction and time-dependent effects significantly influence long-term IAB behavior. In addition, relatively low rotational stiffness and nonlinear behavior of common abutment-to-backwall connections influence long-term response. The proposed numerical modeling methodologies are practical and reasonably predict long-term IAB behavior and response under thermal loading.