下承式钢管混凝土系杆拱桥的冲击系数研究

以泰兴滨江大桥为例，根据下承式钢管混凝土系杆拱桥的结构特点，采用大型通用有限元软件ANSYS对该桥进行有限元离散。采用梁单元beam4模拟钢管混凝土拱肋（内部混凝土及外部钢管）、系杆及横梁等构件，用杆单元Iinks模拟吊杆，用壳单元she1163模拟桥面铺装层，用实体单元solid45模拟桥面系的预制空心板部分，建立了系杆拱桥的空间计算的有限元模型，进行模态分析，得到各阶自振频率及振型。建立四分之一车辆模型作用下的拱桥车桥耦合振动模型，并利用MATLAB语言编制程序，分析了移动车辆荷载作用下下承式钢管混凝土系杆拱桥的响应，系统地得到了该桥在不同车速，不同车道，不同阻尼，不同路况的振动响应等力学性能。本文所得出的主要结论和有关研究成果可为大跨度钢管混凝土系杆拱桥设计时的冲击系数取值，研究车辆对系杆拱桥的冲击性能和后期桥梁养护确定荷载效应分析提供参考。

Study on ImpactCoefficientofUnder-supportedCFSTArchBridge

With the method of finite elements soitware-ANSYS and the characteristics of under-supported CFST arch bridge, this thesis studies the Binjiang Bridge in Taixing which is an under-supported CFST arch bridge. This thesis simulate the components of CFST arch rib （internal concrete and external steel tube）, ties and beams with beam element beam4;the boom with tube unit link8; the bridge deck pavement with shell element shell63; the fabricated hollow slab of the bridge deck with solid45; thus, sets up the finite element model of the spatial computation of the bridge, and then obtains the each order vibration frequency and vibration model data. The axle coupling vibration model of the arch bridge is constructed under the action of a quarter vehicle model. MATLAB programming is employed to analyze dynamic response of under-supported CFST arch bridge under the mobile load condition. Consequently, vibration response of mechanics performances is obtained under different speed, lane, damping and road condition. The conclusions and relevant research results provide reference for impact coefficient during the design, the researches of vehicles impact coefficient and load effect analysis of the later maintenance of the long-span CFST arch bridge.