Study Of The Superlong Span Cable-stayed Bridge

Among a lot of scheme selections of ultra-long span bridges, the cable-stayed bridge has won increasing popularity for bridge designers, becoming the most competitive bridge type along with the suspension bridge. CoMpared with the latter, the former boasts an obvious economic advantage without construction of large-scale anchors. Therefore, the issue of ultimate span length of cable-stayed bridge comes into being.This thesis first introduces the various classification methods of the cable-stayed bridge, followed by the development history of the cable-stayed bridge, some early research on the ultimate span length of cable-stayed bridge and kinds of innovative design conceptions of the ultra-long span cable-stayed bridge. The thesis also describes the basic processes of the modern cable-stayed bridge designing and its static analysis and calculation, and briefly represents the methods of cable force adjustment in ideal finished dead state and reasonable construction state. Based on the being-constructed Bohai Bay Bridge and the above-mentioned theoretical guidance, the author sets up a preliminary design of V-shaped-pylon cable-stayed bridge with a span of2000meters. By applying MIDAS/Civil, a large-scale structural analysis software and using the minimum bending energy method, the author also makes a preliminary estimate of the cable force in reasonable construction state and a forward analysis of the construction stage, and finally obtain the results of main girder static analysis in construction stage and completion stage. Though analyzing such results, it is indicated that the span limit of cable-stayed bridge is determined by the lateral static wind load effect on main girder strength and the axial stress of main girder. Besides, it is found that the stress of local girder section near the abutment increase abruptly under the influence of vehicle load, thus calling for the strengthening of the local cross sections.