Experimental Study On The Wind Induced Response Of Lifting Section Of Bridge

The period of bridge construction is much less than that of the bridge on-period and the design wind speed of the bridge construction stage is usually less than that of the bridge operating.However,compared with the bridge in completion stage,there are more adverse disaster risks in construction stage.At the present stage,there are many researches on wind resistance in bridge construction.But,the researches on the bridge in a certain concrete hoisting construction is less.Up to now,the hoisting safety accident caused by wind have not been happened.However,as more and more bridges across rivers,sea and valleys appear,the influence of wind on hoisting construction becomes more and more important.Therefore,it is very necessary to study the wind induced response of the bridge in the hoisting process.In this paper,taking Sutong Bridge as the engineering background,the dynamic characteristics,static wind response and vibration response of the lifting section of the standard beam have been studied.The research work includes the following aspects:(1)The development process,research contents and research methods of bridge wind resistance are introduced.And then introduces the construction methods of the superstructure of bridge structure(specifically hoisting construction method).The research status of wind resistance in bridge construction stage is summarized.(2)The dynamic characteristics of the lifting section under two hoisting modes of two slings and four slings were analyzed respectively.The modal and natural frequency of the structure were obtained,which provided the necessary parameters for the wind tunnel test of the model.In addition,the influence of the changes of hoisting length,hanging point spacing of structural parameters on the vibration characteristics of the lifting section were studied.(3)The paper obtained the mean value,standard deviation,skewness and kurtosis of the static six component coefficient under different wind deflection angles and wind angles of attack through the wind tunnel experiment,analyzed the influence on the six-component force by seal.The static wind response of the lifting section was calculated,and the responses of the lifting section under different wind speed and wind deflection angles were analyzed.(4)The vibration measurement of the lifting segment model has been accomplished by using the non-contact strain displacement video measuring instrument(high speed camera technology).The paper obtained the vibration responses of the lifting section under different wind speed,wind deflection angles and wind attack angle,analyzed the amplitude anddamping ratio under different hoisting method,deflection angles,attack angles and wind speed.