Response analyses of a hybrid cable-supported and sea-crossing bridge subjected to pulse-like ground motions and hydrodynamic force

Abstract

The Hybrid Cable-Supported Bridge System (HCSBS), renowned for its exceptional spanning capabilities, has become a coveted design for sea-crossing structures. Its appeal lies in the integration of the superior attributes of cable-stayed and suspension bridges. However, this system exhibits a high sensitivity and vulnerability to long-duration, pulse-like ground motions (PLGMs) and hydrodynamic forces (HFs) instigated by seawater. This study conducts an in-depth investigation into the dynamic behavior of an advanced and innovative HCSBS structure when subjected to PLGMs and HFs. A 3D Finite Element (FE) model of the Xihoumen Bridge, a sea-crossing structure with a main span length of 1488 m, is developed via the ANSYS software platform. This model aids in assessing the impact of various pulse-like effects, such as the Fling-step effect, directivity effect, pulse amplitude, and pulse period, on the response of the Hybrid Cable-Supported Sea-Crossing Bridge (HCSSCB). Additionally, two well-established techniques, the Morison Equation (ME) and Radiation Wave Theory (RWT), are employed to evaluate the influence of HFs on the response of the intricate HCSSCB, specifically in the vicinity of the pile foundation. It is worth noting that the ME may overestimate the HFs acting on the pile foundation. Furthermore, it is revealed that when impulse seismic action is considered, HFs can significantly amplify the displacement and force requirements of the HCSSCB.