The seismic response of cable-stayed bridges is characterised by complicated interactions between the deck and the towers. These are influenced by the possible damage in the structure, and also by design choices or constraints such as the tower shape, the span, the cable arrangements, the support conditions and the type of foundation soil. The aim of this work is to assess the influence of these effects on the seismic behaviour of a large number of cable-stayed bridge finite element models. The results of the nonlinear dynamic analyses show the importance of the tower geometry. This is especially significant in short-span bridges with abrupt changes in the inclination of the lateral tower legs, which can lead to large levels of damage in the form of concrete cracking, reinforcement yielding and overall energy dissipation. Finally, design recommendations are proposed to improve the seismic response of the towers.

This research examines the seismic behavior of a cable-stayed bridge featuring concrete-filled steel tube (CFST) pylons, which includes the seesaw system. The objective of the study is to assess the efficacy of the seesaw system in mitigating the seismic response of the bridge across various earthquake scenarios, while also accounting for the implications of soil-structure interaction (SSI). A comprehensive finite element model of the bridge is constructed, incorporating the CFST pylons, cable system, and the novel seesaw energy dissipation system. This model is tested against a range of ground motions that reflect different seismic hazard levels and characteristics. The impact of SSI is analyzed through a series of parametric studies that explore various soil conditions and foundation types. The findings indicate that the implementation of the seesaw system markedly decreases the seismic demands placed on the bridge structure, particularly regarding deck displacements, pylon base shear, and cable forces. Furthermore, the study underscores the significant influence of SSI on the dynamic behavior of the bridge system, emphasizing the necessity of its inclusion in seismic design and analysis. This research enhances the understanding of seismic protection strategies for cable-stayed bridges, providing valuable insights into the advantages of integrating energy dissipation systems and recognizing the importance of SSI effects in evaluating seismic performance.

This study addresses the critical need to understand the seismic behavior of cable-stayed bridges under Multi-Support Excitation (MSE) in order to mitigate earthquake-induced damage to these structures. The primary focus is on the investigation of response amplification phenomena and their seismic implications for cable-stayed bridges. Through a detailed comparative analysis of MSE and Synchronous Excitation (SE) across various structural locations, the study evaluates the impact of site-specific recorded ground motions of different earthquake categories. A pragmatic framework is developed to simulate realistic MSE ground motions for diverse earthquake scenarios, emphasizing the necessity of considering MSE in bridge design. The findings reveal a significant amplification of the design requirements due to antisymmetric mode excitation and increased tower and pier motions. The study also identified the need for in-depth analysis of cable-stayed bridges to address the increased vulnerability of tower-adjacent areas and to devise targeted reinforcement strategies of vulnerable components. These insights are critical for advancing seismic design practices and improving the resilience of cable-stayed bridges, contributing to safer urban infrastructure.