大跨连续钢桁拱桥动力系数影响因素研究

Study on dynamic coefficient influence factors of continuous steel truss arch bridge with large span

以南京大胜关长江大桥为研究对象,建立其车桥耦合动力分析模型,采用逐步积分法求解动力方程,以动力系数作评判标准,讨论行车速度、阻尼比、行车方向、车辆数、吊杆布置方式等参数对动力性能的影响。结果表明:动力系数随行车速度的提高而增大;吊杆索力的动力系数与无应力索长成反比;随着阻尼比的增大,各构件动力系数均有所降低;同向行驶时,两侧对称构件动力系数稍有差别;异向行驶时中桁动力系数低于同向行驶的值且两侧对称构件动力系数差别较大。动力系数不随车辆数的增加而增大;尼尔森体系各构件的动力系数出现了不同程度的减小,可见尼尔森体系有利于提高结构的动力性能。

By taking the Dashengguan Bridge across the Yangtze River in Nanjing as a research object,the vehicle-bridge coupling dynamic analysis model is established and the step-by-step integration method is applied to solve the dynamic equation.Dynamic performance influence factors,such as running speed,damping ratio,traffic direction,vehicle number,suspender layout mode and so on are discussed in this paper by using dynamic coefficients as the judging standards.The results show that：dynamic coefficients are increased with the growth of running speed,but the suspender force dynamic coefficients are inversely proportional to unstressed cable lengths;dynamic coefficients are decreased slightly when the damping ratio increase.When the vehicles run in the same direction,the dynamic coefficients of symmetric components on the upstream and downstream sides are slightly different.While the vehicles run in different directions,the dynamic coefficients of middle truss components are lower than the results in the same direction,and the dynamic coefficients of symmetric components are distinctly different;the dynamic coefficients are not increased with the growth of the number of vehicle,and each component＇s dynamic coefficient in the Nielsen system decreases in different degrees,therefore the Nielsen system is beneficial to improve the structure dynamic performance.