Geometrically Nonlinear Stability of Curved Continuous Rigid Frame Bridges with Initial High Pier Imperfections at Largest Cantilever Stage

Abstract

In this study, we investigated the geometrically nonlinear stability (GNS) of curved continuous rigid frame bridges (CRFB) with initial high pier imperfections at the largest cantilever stage. The stability safety factors were computed and compared for models in an ideal state, initial material imperfection state, initial tilt sate, initial bend state, or with different pier types, respectively. The stability safety factors decrease when geometrically nonlinear effects are considered, and decrease to greater extent when the initial material imperfection appears in the middle and lower portions of the pier. A cross section in the double-limb piers causes even greater decrease in stability. Initial tilt and initial bend also decrease stability, especially the latterin practice, it is crucial to reduce initial bend as much as possible to ensure a safe structure. These factors affect stability to nearly the same extent regardless of whether a double-limb pier or single-limb pier is utilized. Taken together, these results suggest that GNS analysis is necessary to fully comprehensively assess the safety of a curved CRFB with high piers. Index Terms-Curved continuous rigid frame bridge (CRFB), high pier, geometrically nonlinear analysis (GNS), stability safety factor, finite element (FE) method, initial imperfections.