Dynamic Stability of Long-Span CFST Arch Bridge under Action of Near-Fault Ground Motions

In order to research the dynamic stability performances of long-span CFST (concrete-filled steel tubular) arch bridges under the action of near-fault ground motions, an arch bridge with a 132 m main span was taken as the engineering background, and seismic records of the Chi-Chi earthquake in Taiwan, China were set as transverse inputs. The incremental dynamic analysis (IDA) was adopted to determine the critical load of dynamic instability. To increase the efficiency of IDA, the parallel high-performance numerical computing was employed. In addition, the problem of strengthening IDA curve cluster convergence was discussed. The research result shows that near-fault pulse-like ground motions are likely to bring about a great damage and result in nonlinear dynamical limit-load instability, and the corresponding critical load is decreased evidently. Weighted average peak ground acceleration, an new intensity measure, can make the discreteness of IDA curve cluster be improved significantly to avail to reveal the dynamic instability characteristics of CFST arch bridges caused by near-fault ground motions.