Research on the Seismic Mitigation and Isolation Performance of DPSR-MRD in Bridges and Shake Table Tests

To address the limitations of conventional magnetorheological (MR) dampers in bridge engineering, particularly their lack of semi-active control algorithms and inadequate structural adaptability, this study develops a novel dual-chamber self-centering MR damper (DPSR-MRD) with an energy-feedback-based semi-active control strategy. The device integrates dual-chamber fluid interaction (MR fluid in the liquid cylinder and nitrogen gas in the gas cylinder) with a self-centering mechanism, enabling dynamic stiffness adjustment and bidirectional displacement control. An embedded control module adjusts current in real time using accelerometer feedback, while an energy-based algorithm optimizes damping force distribution, significantly improving seismic energy dissipation. Shaking table tests demonstrate the DPSR-MRD's superior performance under multidirectional seismic excitation, achieving 40.33%–47.99% reduction in mid-span displacement, up to 69.9% decrease in peak pier strain, and effective mitigation of localized stress concentration through asymmetric displacement control. Numerical simulations reveal its multi-scale control mechanism: macroscopically reducing overall structural response (up to 71.4% displacement reduction) and microscopically suppressing pier damage through magnetorheological coupling (264.94% reduction in strain). The DPSR-MRD combines adaptive stiffness reconfiguration, multi-modal energy dissipation, and fail-safe protection, offering a robust intelligent solution for bridge seismic mitigation and advancing MR technology applications in civil engineering disaster prevention.