Analysis of dynamic characteristics of long-span railway extradosed bridge

In order to ensure the safety and reliability of the mechanical performance of the whole bridge in the operation stage of the completed bridge, this paper takes an Extradosed bridge, Panzhihua Jinshajiang bridge of Chengdu-Kunming Railway, as the research background, analyzes and studies the longitudinal resonance dynamic characteristics of the short tower cable-stayed bridge structure when the train load acts on the main beam under the condition of completed bridge. The longitudinal vibration of the main girder caused by live load will directly affect the safety and use of the expansion joint device at the abutment, and the damage of the expansion device will lead to the safety and reliability of vehicles in the later operation stage. The dynamic response of the structure caused by the different speed of live load is analyzed. The results show that when there is no significant difference between the live load action speed and the estimated longitudinal bridge resonance speed, there is no significant difference between the longitudinal bridge loading frequency when the live load passes through the bridge and the first-order longitudinal vibration frequency of the bridge. A longitudinal resonance phenomenon can be observed in Jinshajiang bridge, in which the dynamic response of the main beam and the main tower is obvious.