Behavior of partially concrete-filled steel tube bridge piers under bi-directional seismic excitations: Fid-Bau Portal

Behavior of partially concrete-filled steel tube bridge piers under bi-directional seismic excitations

Yuan, Huihui / Dang, Ji / Aoki, Tetsuhiko

Abstract During the past decades, amounts of research efforts have been concentrated to investigate basic characteristics of the seismic response of steel bridge piers by cyclic bi-directional loading tests or finite element analysis. However, dynamic test results on partially concrete-filled steel tube (PCFST) bridge piers under coupled ground motions in two horizontal directions are insufficient. To investigate the behavior of PCFST bridge piers under bi-directional seismic excitations, a series of cyclic static loading tests and single- and bi-directional hybrid (pseudo-dynamic) loading tests for circular-section test specimens with three different concrete-filled ratios were performed in this study. The failure patterns were observed after the tests. The experimental results showed that the restoring force of PCFST bridge piers obtained in bi-directional loading tests was almost the same as that obtained in single-directional loading tests. However, deformation capacity deteriorated considerably when subjected to bi-directional dynamic loadings. This study also shows that the seismic behavior of PCFST bridge piers can be effectively improved if the concrete fill height is significantly increased.

Highlights • We conduct bidirectional pseudo-dynamic tests on PCFST bridge piers. • Adequate concrete fill can effectively improve seismic behavior of PCFST piers. • Low concrete fill may lead to severe damage or collapse during earthquakes. • Bidirectional loadings deteriorate deformation capacity of piers considerably. • A more reasonable bi-directional seismic verification method is proposed.