A Preliminary Study Of The Cable Truss Structure In The Special Suspension Bridge Of Railway

As a new kind of tension-tensile structure system, Cable truss bridges have a good performance at high ratios of live load and dead load. Compared with ordinary suspension bridge so it has a good application prospect in the field of railway Bridges. In this paper, The mechanical behavior and the conceptual design of the single-span cable truss railway suspension bridge were studied, furthermore, some references for preliminary design of this kind bridges were provided.Based on a 240-meter-long cable truss railway suspension bridge, the FEM software MIDAS was introduced to simulation the railway suspension bridge and Cable Truss railway suspension bridge in this study, then their finished bridge state,the dynamic characteristics and the integral stiffness under moving load had been analysised. Through these upwards research, the paper draws the following conclusions:Firstly, at finished bridge state, compared with ordinary suspension bridge, the tension in main cable of the Cable Truss suspension bridge is higher, which means the gravity stiffness of the main cable is relatively larger and the integral rigidity of the Cable Truss suspension bridge is better.Secondly, through the modal analysis, the transverse and vertical rigidities of the suspension bridge improved as the cable truss structure introduced.Thirdly, under moving load, the cable truss suspension bridge has a small mid-span deflection, the stress and the internal force increment of its cable, suspender and tower are also small.Finally, the integral rigidity of the cable truss suspension bridge is better than that of the suspension bridge of its counterpart with similar total internal forces in cable and suspender. It shows that the cable truss suspension bridge has a good prospect of application in railway bridges.