Experiment on seismic performance of concrete filled steel tubular arch-rib under multi-shaking-tables

Abstract

During the last two decades, a large number of concrete filled steel tubular (CFST) arch bridges had been built in China. However, the experiment on seismic performance of CFST structural arch rib was seldom conducted especially under spatial wave excitation. In order to understand the seismic behaviors of CFST arch bridges, a scaled 1:10 model of CFST arch-rib was constructed with fully compensative mass. The test was carried out uniform and non-uniform excitations under a Multi-shaking-tables array system in Fuzhou University, China. Artificial waves and several recorded ground motions were employed to identify the basically dynamic behavior and to evaluate the elastic and plastic seismic performance of this arch-rib model.The testing results indicate that the seismic responses of CFST arch-rib are highly related to the predominant frequencies, ranges as well as peak magnitudes of input waves’ spectrum. The testing results also show that the transverse seismic response is more distinct than that longitudinal response, and the bi-directional excitation has much larger responses than the single excitation. Furthermore, the non-uniform excitation has more significant effect than the uniform wave especially on the displacement responses. Therefore, the earthquake effect on the CFST arch bridge need necessary to take account of bi-directional excitation and non-uniform excitation.In addition, the testing indicates that the CFST arch-rib structure has performed the nonlinear and plastic behavior especially under intensive excitations of El-centro wave and Hanshin wave. However, the natural frequencies or stiffness of the CFST arch-rib model don’t have significant decrease and there is no distinct crack or damage on the steel surface because of the hooping effect on the core concrete. This indicates that the CFST arch-rib structure has a favorable seismic behavior and ductility.