意大利高速铁路Sesia大桥的动力特性及车桥耦合振动分析

Dynamic characteristics and coupling vehicle-bridge vibration analysis of the high speed railway Sesia Bridge in Italy

建立了包括钢轨、轨枕、道床、梁体在内的意大利Sesia大桥空间有限元模型,对桥梁的自振特性进行了计算和实测分析。按照轮轨密贴接触假定推导了车-桥系统耦合运动方程组,以德国低干扰谱生成轨道不平顺样本作为激励源,对意大利ETR500Y高速列车通过Sesia大桥引起的桥梁动力响应和桥上车辆的振动响应进行了计算分析,讨论了共振车速的范围并对桥上车辆的运行安全性和平稳性进行了评价。部分计算结果与实测数据进行了对比,吻合较好,从而验证了所建立的模型及分析方法的精度和有效性。结果表明:Sesia大桥结构刚度很大,当列车以288 km/h的速度通过时,挠跨比只有1/17510;当列车以340 km/h的速度通过时,桥梁的竖向位移出现了一个较为明显的峰值,说明这一速度可能引发结构共振;桥上车辆的各项动力指标响应值均很小,能较好地满足高速行车要求。

A 3-D rail-sleeper-ballast-beam FE model was established for the Sesia Bridge in Italy.The natural vibration characteristics of the bridge were analyzed by numerical study and field measurements.The coupled equations of motion were deduced for the vehicle-bridge system on the basis of a corresponding assumption on the wheel-track interaction both in lateral and vertical directions.Taking the track irregularity samples based on German low disturb track spectra as excitation,the dynamic responses of the Sesia Bridge and the Italian high-speed ETR500Y train vehicles on the bridge were analyzed.The resonant train speeds were discussed and the running safety and stability of the train vehicles were evaluated.Some results were compared with the measured ones and a good agreement was found,thus the efficiency and validity of the established bridge model and proposed method were verified.Numerical results show that the Sesia Bridge is very stiff: as the train runs at the speed of 288km/h,the ratio of dynamic deflection to bridge span is only 1/17510.The vertical displacement of the bridge appears a peak value at the train speed of 340 km/h,indicating that bridge resonance may occur.All the dynamic indices of the vehicle on the bridge are small,thus can well satisfy the high-speed train passage.