Parameter optimization of damped cable system for vibration control of long-span bridges

This paper proposes a method for controlling wind-induced vibrations of long-span bridges using a compound damped cable system (CDCS). The CDCS effectively extends the support rod length of dampers which is limited for traditional dampers mounted in bridge girders. The CDCS can provide significant energy dissipation capacity. Additionally, an optimization approach based on the linear quadratic regulator (LQR) control algorithm is proposed for the CDCS. The objective is to minimize the bridge’s energy integral during free vibration. Verification of this approach is performed using a simply supported beam with the gradient-based optimizer (GBO) algorithm. Then, the performance of CDCS on a practical suspension bridge is investigated. The results show that the CDCS can effectively reduce the vibration response of the bridge. Specifically, when the parameters of the CDCS are optimized for a single-mode vibration, the response of the first four vertical bending modes of the bridge vibration decreases by 70%, 92%, 92%, and 88%, respectively; when the parameters of the CDCS are optimized for a multi-mode vibration, the response decreases by 68%, 90%, 90%, and 88%, respectively. •Introducing Damped Cable System (DCS) for long-span bridges control.•Proposing multi-modal and multi-parameter optimization algorithm for DCS.•Validating algorithm via comparative analysis with GBO algorithm.•Presenting a numerical example of a practical suspension bridge with DCS.