Field monitoring of skewed integral abutment bridges

Integral abutment bridges (IABs) have come of interest due to their decreased construction and maintenance costs in comparison to conventional jointed bridges. Because their structural behavior is still not fully understood, two IABs (of different geometry and soil properties) were selected for field monitoring. The monitored bridges, located in northern Illinois, include a 30-degree skew four-span continuous IAB and a 42.5-degree skew single-span IAB, both of which have steel superstructures and incorporate pile top relief for HP14 piles. Construction of the bridges began in the spring of 2013, and instrumentation data has been collected since May 2014. Field instrumentation includes pile, girder, and concrete embedment strain gages, as well as displacement transducers and tiltmeters. This paper presents findings from the first full year of data collection, with the bridges experiencing a summer-to-winter-to-summer temperature cycle. Comparisons are also made with 3-D finite element models of each instrumented IAB. As expected, results of pile strains, girder strains, global movements, and abutment rotations all show clear trends with temperature. The absolute and relative values of these findings help to enhance the detailed understanding of IAB behavior, as well as improve IAB analytical modeling.