Analysis Of Wind Resistance For Long Span Continuous Rigid Frame Bridges

In this paper, wind resistant of long span bridges in cantilever state is analysed..The author focus on main factors that should be taken into account in design, basic theories of structural analysis, calculation content, calculation procgram, calculation methods, etc..And the usable formula of wind loading inconstruction is given. The main results of this paper are included below:First ,in this paper the author analysed the essential features of the wind and the wind effects on bridges,. And wind-induced vibration is described I particular. The wind-induced vibration consists of wind-excited vibration and enforced vibration. Although bridge flutter is the most dangrous phenomenon in the wind-induced vibration, it has been solved. The bridge buffeting which is include forced vibration is the most important phenomenon in the wind-induced vibration.Second, two methods for wind effects on bridges are discussed, which include the method of gust response factors and the method of buffeting response spectrum.Thirdly, from the requirement of practical engineering, the accurate analysis method is simplifide according through the parametric analysis, the formula for engineering application of the second method is presented.Forthly, structural analysis of this paper is based on the finite element method (FEM) and calculation theory of long span bridge. At first, structure units and construction phases are divided into. Mechanical model , stiffness matrix, load matrix and displacement matrix of the structure are built stage by stage. Then, unit stiffness equations and integrated stiffness equations and integrated stiffness equations are established respectively according to geometric conditions and equilibrium conditions among the units. Internal force and displacement in any construction(service) phase are resolved.Finally, a realengineering example show that the two methods.And the result of the engineering example show that the stress calculated by buffeting response spectrum method is larger than which calculated from the gust pesponse factor methed.