EXPERIMENTAL STUDY ON VIBRATION OF RAILWAY TRUSS BRIDGE

With the increased carrying capacity and train speed, not only the vertical load increase, but also the additional loads including the impulse force, brake power and horizontal rocking force of the train improve, which has a serious impact on the static and dynamic charactaristics of the existing bridge structures. The dynamic behavior experiment was conducted by the train marshalling on the railway truss bridge over Jing-shi highway at Suo-Huang railway line. The change law of vibration behavior, dynamic stress, dynamic deflection, and other technical parameters of safety transportation were measured. At the same time, the derailment factors and offload ratios at different train speeds were also measured when the test train running across the bridge. Finally, the free vibration characteristics were obtained by measuring pulsation or residual vibration. The test results show that, most vibration indexes satisfy the code limit, except the maximum lateral amplitude at middle span, which a little larger then the code normal value, and the measured lateral natural frequency of the bridge, which a little less then the safety degree limit of code. These results indicate that the lateral stiffness of the bridge is not enough strong. The experiment conclusion is provided reference and reference for proper maintenance, management and use of the similar bridge structures in future.