Experimental and numerical analysis on the limited ductility of H-shaped concrete cable-stayed bridge tower

When a cable-stayed bridge is subjected to strong ground motions during an earthquake, the vibration of the tower column is much stronger and more severe in the transverse direction than the longitudinal direction, due to the lateral restriction between the tower and the main girder. To address this issue, the current seismic design of cable-stayed bridge recommends that a larger reinforcement ratio in tower column be used to achieve the target seismic performance (i.e., remaining elastic). This entails an increased number of the piles and the reinforcement volume as well and thus such a design is often not cost-effective. Alternatively, the tower column can be designed to have allowable ductile behaviour for saving costs. Therefore, this study aimed to verify the ductility margin and the allowable ductile performance of the H-shaped concrete tower, by studying its lateral elastic-plastic behaviour and damage mechanism through incremental dynamic analysis, and its limited ductility against the lateral inertial forces based on quasi-static test.