Response of curved steel bridges to seismic loading

It has been reported that upwards of one-third of all steel bridges being constructed today are horizontally curved structures. As a result of increased design and construction of curved, steel, I- and box girder bridges, during the past fifteen years extensive research has been dedicated to improving the understanding of their behavior. However, despite this extensive effort, there has been rather limited study related to their dynamic and, more specifically, their seismic response. This paper will summarize recent work at the Pennsylvania State University that computationally examined the behavior of curved I-girder bridges under seismic loads. These studies have: (a) focused on the effect of varying global parameters, such as girder spacing, cross frame spacing and location of lower lateral bracing, on load levels in cross frame members and at the bearings; and (b) developed fragility curves using statistically based modeling techniques. Models that were used and their motivation, including a discussion of statistical techniques that were employed, will be discussed. In addition, findings from the studies, including the discussion of influential seismic parameters and the presentation of representative fragility curves, will be given.