Bi-axial Quasi-static Testing Research of High Hollow Reinforced Concrete Piers

While the high-pier bridges with large-span are widely used,the seismic problems of high-pier bridges become extremely prominent.In this study,bi-directional quasi-static testing on 6 scaled models of high hollow piers was conducted,and the nonlinear finite element(FE) model was established to simulate the seismic behavior of high hollow reinforced concrete pier under bi-directional cycle loading,in which,two factors,namely axial compression ratio and slenderness ratio were considered.The main conclusions drawn from the testing and analysis are as follows:(1) The high-hollow reinforced concrete piers under the axial loading and bi-directional cycle loading mainly result in typical flexural failure and the plastic hinge occurs at the bottom of the pier.Meanwhile,the shear effect can′t be neglected.(2) Mutual coupling occurs while the high hollow pier undertakes the bi-directional horizontal loading.The damage to the high piers may be caused under the mutual coupling effects.Especially,in the direction of to smaller rigidity the piers may be damaged seriously.The cracking may occur and the piers may step into the plastic stage in advance.(3) The proposed nonlinear FE model can predict the cracking and the failure of the high piers under bi-directional reversed low-cycle loading.The results from the FE model may accord well with those from the testing,such as the hysteresis characteristics and skeleton curves.(4) The proposed multi-dimensional model of loaddisplacement restoring force can reflect the seismic performance of reinforced concrete thin-walled high hollow piers and can be referenced in the seismic design and dynamic analysis of the high piers.