Analysis of instability process of asymmetric suspension bridge under aerostatic wind load
As flexible structures,suspension bridges will produce large deformation and even instability under the action of strong wind,which will lead to a large safety hazard.Taking a real bridge as the engineering background,considering the nonlinearities of the bridge structure and the wind load acting on the bridge structure,the critical wind speed of the bridge is about 120 m/s by using the incremental internal and external double iteration method.The variation rules of the natural vibration characteristics of the bridge under the influence of symmetry and rise span ratio are obtained by using the finite element software ANSYS.The results show that the structural symmetry has little effect on the natural vibration frequency,and the frequency of asymmetric structure increases only in the high order.For the rise span ratio,the overall stiffness of the bridge increases with the decrease of the rise span ratio,and the natural vibration frequency also increases.After the application of wind load,the static wind stability analysis is carried out to analyze the instability process and the deformation and internal force changes of the bridge components under the change of wind speed.It is found that the three-component force coefficient changes with the increase of wind speed,which makes the vertical deformation direction of the bridge change from downward to upward.Except for the wind load acting on the main beam and main cable,the wind load on other bridge structures can be ignored.During the instability,the stress of the main cable and suspender on the windward side of the main girder is greatly reduced,and the reduction ratio is about 30％.The instability process can be seen as the process of the stress reduction and withdrawal from the original function due to the relaxation of the cable and suspender.
suspension bridgestatic wind stabilitystructure safetynonlinear theory
NETL
NSTL
万方数据
维普
