中下承式拱桥吊杆应力冲击系数不均匀性研究

摘要

In order to investigate the Non-uniformity of stress impact factor of suspenders on half-through or though arch bridges under dynamic loading of road vehicles, the vehicle-bridge vibration based analysis method was proposed. The vehicle was modeled as a four-degree-of-freedom system and the vibration equations of the vehicle model were deduced based on the D'Alembert principle. Then finite element method was used to discretize the bridge and a finite element model was set up. According to the conditions of displacement and force compatibility between vehicle and bridge, the vibration equations of vehicle and bridge are coupled. A professional procedure VBAP was programmed based on Newmark-β algorithm in MATLAB to analyze the vehicle-bridge system's coupled vibration. Taking a concrete-filled steel tube arch bridge as example, the influences of damping ratio, road roughness, vehicle weight and vehicle speed on stress impact factors of suspenders were analysed using the method and program mentioned in the paper.%为研究中下承式拱桥在公路车辆作用下的吊杆冲击系数不均匀性问题,提出基于车桥耦合振动的公路桥梁动力响应分析方法.首先,将车辆简化为4个自由度的整车模型,根据D' Alembert原理推导了车辆振动方程,将桥梁离散为有限元模型,根据车辆与桥梁接触点处位移与力的协调条件耦合二者的振动方程;然后,采用Newmark-β算法,基于MATLAB语言编制了公路桥梁车桥耦合振动计算程序VBAP;最后,以某钢管混凝土拱桥为例,利用该方法与程序分析结构阻尼、桥上路面粗糙度、车重及车速对吊杆应力冲击系数的影响.