道路交通引起城市人行钢桥振动特性分析

为了研究道路交通引起的城市人行钢桥振动特性,基于线性动力学理论,采用MSC.MARC建立全桥三维模型进行瞬态动力分析.通过对人行钢桥简化模型的动力求解,拟合出动力变化系数与频率比关系曲线,并对道路交通荷载引起的人行桥振动问题进行理论分析.按照实际人群密度和实测道路交通荷载激励分别计算了人行钢桥的动力响应.分析结果表明,在道路交通荷载激励下人行桥上部结构的振动较大,对于自振频率较高的城市人行钢桥,道路交通荷载对人行桥振动的影响更为明显,城市人行桥振动控制应当考虑综合激励环境下的影响.

Feature analysis of urban pedestrian steel bridge vibration caused by road traffic

In order to study of the characteristics of urban pedestrian steel bridge vibration caused by road traffic,a three-dimensional model of bridge is built by MSC.MARC to conduct the transient dynamic analysis based on the linear dynamics theory.Through the dynamic solution to the simplified model of pedestrian steel bridge,dynamics variable coefficient and frequency ratio curve are combined to process the theoretical analysis of the pedestrian bridge vibration caused by the load of road traffic.Considering actual people density and measured road traffic loads excitation,the dynamic response of pedestrian steel bridge is analyzed separately.The results indicate that the superstructure of pedestrian bridge has a larger vibration under road traffic loads excitation.Compared with the pedestrian-induced force,road traffic loads have a more obvious impact on the urban pedestrian steel bridges with higher natural frequency.Therefore,with regard to the urban pedestrian steel bridge vibration control,the impact of overall ambient excitation should be taken into account.