Behavior of curved and skewed bridges with integral abutments

• The behavior of curved and skewed bridges with integral abutments is examined.
• An integral abutment bridge under varying environmental conditions is monitored.
• A 3D finite element model is developed and validated against the measured data.
• The influence of curvature and skew on the bridge behavior is studied.

Horizontally curved steel girder bridges are being designed with integral abutments due to their merits in terms of cost, constructability and maintenance. This type of bridges is relatively new in the United States and their performance evaluation is deemed difficult. Especially, the behavior of such bridges under thermal load conditions is not well understood and relevant code guidelines are not sufficiently provided. The purpose of this study was to investigate the behavior of a curved and skewed bridge with integral abutments through a numerical analysis and field monitoring-oriented program. A newly constructed, one lane, three span, horizontally-curved, integral abutment bridge was instrumented using a field monitoring system to capture the bridge behavior under change in ambient conditions and was tested using a dump truck traveling across the bridge at a walk pace. A three dimensional FE model was established and its predictions were reasonably compared with the collected data. Subsequently, a parametric study was performed to investigate the influence of curvature and skew on the bridge behavior under design loading conditions. It was found that the stresses in girders varied with changes in skew and curvature significantly. With a 10° skew and 0.06 radians arc span length to radius ratio, the curved and skewed integral abutment bridges can be designed as a straight bridge if a 10% increase is applied to the total induced stresses. Thermal stress and its magnitude relative to the maximum stress can reach up to 3 ksi and 15% of the maximum stress, respectively.