考虑荷载随机性的人行桥人致振动计算方法研究

随着人行桥大跨轻柔化的发展趋势，行人动力荷载逐渐攀升为人行桥设计中的控制荷载．然而，受行人荷载随机性的影响，如何计算人行桥的人致振动响应却成为桥梁工程设计人员最为棘手的问题．为了建立准确实用的人行桥人致振动响应计算方法，首先提出了改进后的基于瞬时步行参数的行人步行力随机性时域模型，并通过实测手段系统地研究了模型中包括个体间差异性以及个体内部变异性在内的行人步行参数的分布规律．在此基础上阐述了行人流步行过程模态力的集成，建立了行人作用下的人行桥人致振动的模态叠加分析法．本文以43#人行桥为例，将数值模拟结果与人致振动试验数据以及现有各国人行桥设计规范进行了综合的对比分析，验证了考虑随机性后的人行桥人致振动时域分析法的可靠性与实用性．

A Calculation Method for Footbridge Vibration under Stochastic Pedestrian Loading

Pedestrian dynamic load has begun to play the critical role in footbridge design stage due to its construction fashion of long span and more flexibility. However, impeded by the stochastic nature of pedestrian loading, how to calculate the response of footbridge due to pedestrian walking appears as a tough problem for consulting engineers. To develop an accurate and practical method for the calculation of pedestrian induced footbridge vibration, a time domain based stochastic load model for pedestrian walking force is first proposed and expressed in parameters of human instantaneous walking gait, which is followed by an extensive investigation into the distribution law of pedestrian gait parameters through site tests. On the former basis, also illustrated in this paper is the procedure to integrate modal force due to pedestrian walking, as well as the framework to perform a mode superposition transient analysis for footbridges vibration under pedestrian loading. Finally, taking 43# Bridge as an example, the reliability and practicability of this methodology is validated by comparing the results from numerical simulation and from the experimental test, as well as by values determined in accordance to worldwide guidelines for footbridge design.