基于车桥耦合振动的钢管混凝土系杆拱桥动力响应分析
Analysis of concrete-filled steel tubular tied-arch bridge under travelling vehicles

为研究钢管混凝土系杆拱桥在车辆荷载作用下的动力效应，利用ansys二次开发功能编写基于车桥耦合理论的车桥耦合振动分析程序，分析车速、车重以及路面不平顺等级3个因素对拱肋、端部吊杆及桥面跨中等关键部位动力响应的影响。分析结果表明：随车速、车重及桥面不平顺等级降低，桥梁跨中节点位移响应峰值不断增大，拱脚、1/4拱肋及拱顶截面处的应力最大值不断增大，最小值不断减小；但拱顶截面应力响应峰值对车重、车速及桥面不平顺等级的敏感程度较拱脚与1/4拱肋截面处的低。此外，桥梁跨中加速度响应峰值及端部吊杆应力幅对车重20 t最敏感，端部吊杆的应力幅随车速提高反而降低，当桥面不平顺等级为D级时端部吊杆应力幅达到186 MPa。最后，对比车-桥振动响应分析发现，随着桥面不平顺等级降低、行车速度提高，将会引起车体较大的竖向加速度峰值，进而引起桥梁结构较大的竖向位移。
A theoretical research work in relation to the dynamic impact to concrete-filled steel tubular tied-arch bridge under modern travelling vehicles was described. The program for bridge-vehicle coupled vibration is compiled by utilizing the secondary development in finite element analysis software ANSYS. The dynamic response of arch rib, suspender and mid-span are discussed respectively in consideration of different vehicle speed, weight and roughness. The results indicate: with the decrease of vehicle speed, weight, and the deterioration of bridge roughness, the dynamic displacement peak of mid-span and the maximum stress of arch foot, 1/4 arch rib and top section increase obviously, while the minimum stress decrease. The maximum stress of top section is relatively less sensitive to the three factors than other sections. Furthermore, the mid-span acceleration response peak and the end suspender stress amplitude are most sensitive to vehicle 20 t. While the end suspender stress amplitude decrease with the increase of vehicle speed. What’s more, there is a most sensitive weight to the suspender stress amplitude. And the end suspender stress amplitude is 186 MPa (fatigue strength 200 MPa) when the bridge roughness degrades to D. Eventually，it can be found that the deterioration of bridge roughness will cause the larger magnitude of vehicle acceleration peak, which will lead to larger displacement peak of bridge mid-span