Study On Dynamics Of Heavy Haul Train Considering Anti-curves On Bridge

Based on the theory of vehicle-bridge dynamic interaction and taking the32m simply supported prestressed concrete double T-beam bridge on Mengxi to Huazhong line and C70heavy haul train as case study, the dynamic model of vehicle-bridge interaction system on anti-curves is established in this paper and the inter-system iteration method is used for calculation. Taking the time-varying rail irregularities as excitations, the influence of curve radius, train velocity, length of straight lines between curves and super elevation of curves on the vehicle-bridge system are analyzed. The main conclusions are as follows:(1) The train velocity has a significant effect on the train-bridge system. The system dynamic response increases as the velocity increases and so does the dynamic response of bridge substructures. When the velocity arrives at120km/h, some dynamics indexes exceed the safety limit, as a result of which the velocity is suggested to be below120km/h.(2) The curve radius of anti-curves has an obvious influence on the train-bridge system. The dynamic response of the coupling system increases as the curve radius decreases. When the curve radius is600m, some dynamics indexes exceed the safety limit under the condition of design velocity. Therefore, it is suggested that the curve radius should be larger than600m.(3) The length of straight lines between curve lines has little impact on the dynamic response of train-bridge coupling system both on the curves and the straight lines. The straight line connection between two curves only changes the direction of the dynamic response and doesn’t increase the value of dynamic response. So, it is acceptable in some special geometric location to neglect the straight line or set up shorter one.(4) The deficient super elevation and surplus super elevation have some effect on the train-bridge system. According to the analysis, the deficient super elevation has a significant adverse effect on the train-bridge system on curves.(5) The dynamic response of beams and piers increase obviously as the stiffness of bridge substructure decreases, and the lateral displacement of the pier top on the curve segment is almost2times of that on the straight ones. So it is suggested to enlarge the pier stiffness on the curve segment to at least2times of that on the straight ones along the line.