Identification of bridge damping ratio based on time domain singular energy ratio

This study proposes a novel method for identifying bridge damping ratios using the Signal Energy Ratio (SER) derived from vehicle-bridge coupling theory. The effectiveness of the method was verified through theoretical derivation, parameter analysis, and on site testing. A stationary dual-axis test vehicle at mid-span collects body acceleration, enabling indirect derivation of the tire-bridge deck contact point response. The relationship between structural damping ratio and SER is theoretically established. SER is calculated via singular value filtering of the bridge's first-order acceleration half-cycle energy and comparing even/odd half-cycle energies. Results demonstrate high SER sensitivity to damping variations, enabling reliable identification under both single and multiple damage scenarios (damage threshold up to 30%). The method maintains robust identification (coefficient of variation <0.08) even at 20 dB SNR. Requiring only a dual-axis vehicle for rapid full-bridge testing, it significantly reduces human intervention. This approach enhances damping ratio identification robustness and efficiency, providing a new paradigm for indirect measurement techniques with clear application value for rapid condition assessment of medium- and small-span bridges.