The Geometric Nonlinearity Analysis Of Long-span Cable-stayed Bridge

As the traffic constructions of China develop in these years, a number of long-span bridges are to be built to meet the demands of traffic layout. Because of the beautiful sculpt and economic span, cable-stayed bridges become a competitive type of long-span bridges.Firstly, the basic theory of geometric nonlinear analysis for long-span cable-stayed bridge is introduced in this paper. Then three principle factors that affect geometric nonlinearity of cable-stayed bridges are described, which are large displacement, cable sag effects and combined effects of bending moment and axial force; then the finite element methods are introduced separately. And based on these factors, carry on nonlinearity analysis to a long-span cable-stayed bridge which forced dead loads. This paper also contrast the result to the linearity analysis.This paper also discusses the problem about dynamic characteristics and seismic response analysis of the long-span cable-stayed bridge. And apply finite element program to investigate the dynamic characteristics of the long-span cable-stayed bridge, involving the natural frequency and the characteristics of natural model. Based on the method of the seismic response time history analysis, this paper chooses the seismic wave El-Centro and analyses the seismic responses. For long-span bridges, the more rational method for seismic response analysis should be performed considering traveling wave effect. At last, some useful conclusions to the design of this kind of bridges are obtained.The simulation of fluctuating wind field of a long-span cable-stayed bridge is carried out by Matlab program in this paper. A certain cable-stayed bridge is used as an example to carry on the buffeting analysis. The result indicates that the program are reliable. According the analytic process, some useful conclusions are obtained to provide the reference for the design and study of suspension bridges in the future.