大轴重列车作用下桥梁结构的动力响应研究

Research on the Dynamic Response of Bridge Structure under Large Axle Load Train

研究目的:为研究大轴重列车作用下桥梁结构的动力响应,本文以30 t大轴重列车和重载铁路线上常用跨度32 m预应力混凝土简支T梁为研究对象,结合现场实测数据,基于多体动力学理论和有限元法建立大轴重列车-轨道-桥梁三维耦合精细化有限元模型,并验证有限元模型的准确性。通过计算大轴重列车作用下桥梁结构的动力响应,分析大轴重列车编组长度、列车轴重、列车运行速度以及桥墩高度等因素对桥梁结构动力响应的影响规律。研究结论:(1)当列车编组数达到6节以后,列车编组数增加仅影响桥梁结构的动力响应持续时间,不会对桥梁结构的动力响应峰值产生影响,在计算长大编组列车通过中小跨度桥梁时可简化为6节编组进行计算;(2)桥梁结构的动力响应与重载列车的轴重有较明显的相关性,桥梁跨中竖向位移和跨中横向位移均随着列车轴重的提高而增加,增幅呈近似线性增加的趋势;桥梁跨中竖向加速度和跨中横向加速度均随着列车轴重的提高而逐渐增加,且增幅越来越大;(3)桥梁结构的动力响应均随着列车运行速度的提高而增加,跨中加速度响应随列车运行速度的提高增幅比跨中位移响应增幅大;(4)桥梁墩高的变化对桥梁结构的竖向动力响应影响较小,而对横向动力响应影响较大;(5)本研究成果可为重载铁路桥梁的设计和既有线铁路桥梁强化改造提供参考。

Research purposes： In order to study the dynamic response of bridge structure under the action of train with 30 t large axle load and the commonly used 32 m prestressed concrete simply supported T -beam as the object, the 3 -D coupled finite element model of train- track- bridge was established based on the measured data, multi -body dynamics theory and the finite method, and the accuracy of the finite element model was verified. The dynamic response of the train- bridge system under large axle load was calculated, and the influence law of the train length, train axle load, train running speed and pier height on the dynamic response of bridge structure were analyzed. Research conclusions： （ 1 ） The increase of train marshalling number has no effect on the peak value of dynamic response, but it affects the dynamic response duration of bridge structure when it exceeds 6, so 6 section marshalling can be simplified to calculate the small and medium span bridge. （2）The dynamic response of the bridge structure in closely related to the axle load of the heavy load train, the vertical displacement and lateral displacement of the middle of bridge span increase with the increase of the train axle load, and its amplitude is approximately linear; the vertical acceleration and lateral acceleration of the middle of bridge span increase with the increase of the train axle load, and the increase amplitude is increasing. （3）The dynamic response of the bridge structure increases with the increase of the train runningspeed, and the increase of the acceleration response to the middle span of the bridge increases with the increase of the train running speed larger than the mid span displacement response. （4） The change of the height of the bridge pier has little influence to the vertical dynamic response of the bridge structure, but has great influence on the lateral dynamic response. （5）The research results have reference value for the design of heavy haul railway bridge and strengthening reconstruction of existing railway bridge.