Research on seismic resistance of combined system bridge of cable-stayed bridge and irregular arch

Bridges are prone to damage during earthquakes, with large-scale or complex structural systems being particularly sensitive to seismic impacts. Taking the bridge that integrates a cable-stayed bridge with a backless slanted tower and a lower-supported irregular arch bridge as the background, this paper establishes a spatial analysis model for Xiangfeng River Bridge using the finite element software Midas Civil. Based on the concept of structural vibration control design, the concept of time-history response influence factors is introduced to conduct a time-history response parameter analysis of the structure. The study investigates the effects of wind brace arrangement, concrete elastic modulus, length of arch rib concrete sections, and the inclination angle of the pylon on the seismic performance of the bridge. It further compares and analyzes structural vibration control and damping, conducts structural seismic checks, and performs elasto-plastic time-history response analysis at the consolidated positions of the tower, beam, and pier by defining elasto-plastic materials and fiber hinges. The research results indicate that the sensitivity of the overall seismic performance of the structure to different parameters follows the order from strongest to weakest as: pylon inclination angle > length of arch rib concrete sections > concrete elastic modulus > wind brace arrangement. “K”-shaped wind braces are more conducive to structural seismic resistance compared to parallel wind braces, and omitting wind braces will significantly impact the seismic performance of the structure. Increasing the short length of the arch rib concrete sections affects the structural spatial mass distribution and reduces the overall lateral stability of the structure. Received: 26.06.2025 Received in revised form: 10.09.2025 Accepted: 24.11.2025