基于MSD模型的人-桥耦合效应量化分析及简化计算方法

Quantitative Analysis and Simplified Calculation Method of Human-Bridge Interaction Based on MSD Model

基于行人质量-弹簧-阻尼模型建立了人-桥耦合系统运动方程,并采用复模态分析法获取了系统动力特性。在此基础上,量化分析了频率比、质量比和行人间距对桥梁动力特性的影响规律,提出了考虑人-桥耦合效应的简化计算方法。研究表明:对于大跨度人行桥,行人运动会导致结构实际振动频率和阻尼比的改变,其改变程度和规律受质量比、频率比和行人间距以及结构振型影响,如忽略人-桥耦合效应会高估结构响应。通过修正桥梁动力特性并将行人视为步行力施加到人行桥上,计算出的结构响应与考虑人-桥耦合效应的结构响应基本一致,但计算量大幅降低,表明该方法具有较高的精度,可用于快速预估人致振动响应。

Based on pedestrian mass-spring-damping(MSD)model,the governing equation of the human-bridge coupling system is established,and the dynamic characteristics of the system are obtained by complex modal analysis method.On this basis,the influences of the frequency ratio,mass ratio,and pedestrian spacing on the dynamic characteristics of the bridge are quantitatively analyzed to propose a simplified calculation method considering the human-bridge coupling effect.The results show that the pedestrian movement will cause changing in the actual vibration frequency and damping ratio of the bridge for long-span footbridges.The magnitude and regularity of the dynamic change are affected by the human-bridge mass ratio,frequency ratio,pedestrian spacing,as well as the bridge mode.Neglecting the human-bridge coupling effect will cause an overestimation of the bridge response.Through modifying the dynamic properties of the bridge and a walking force of the pedestrian imposed on the bridge,the calculated structural response compares well with that obtained by considering the human-bridge coupling effect.However,the computation is significantly reduced which indicates that the proposed method can be used for a quick analysis of the human-induced vibration response of the footbridge because of the good accuracy.