The Geometric Nonlinearity Analysis Of Long-span Suspension Bridges

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. Suspension bridges are long-span bridges supported by cables.Because of their long span ability and light beautiful structures, suspension bridges are competitive bridge types of long-span bridge.Sta rting with the theoretical development of suspension bridges,this thesis introduces the basic principle of linear-elastic theory, deflection theory and finite displacement theory. Combining the all-function FEM software and the stress analysis of suspension bridge,this thesis presents a numerical method based on the finite displacement Theory of the finite-element for model building and calculating the inner force of suspension bridges, which meets the demands of engineering design.This thesis has considered the three primary geometric nonlinearity factors of the cable sagging effect, the large deflection effect due to changes in geometry and the influence of initial strains, and carry on static&dynamic structure analysis to the structure of suspension bridges with 3D finite-element models on the basis of Ohtsuki doctor's method.We also study the aerostatic stability of suspension bridges under wind.The simulation of lluctuating wind flield of a large span suspended bridge is carried out by Matlab program language in this thesis.A certain suspension bridge is used as an example to carry on the buffeting analysis of suspension bridges.it indicates that the results of program are reliable.According the analytic process,Some useful conclusions are obtained to provide the reference for the design and study of dynamic of suspension bridges in the future.