Vibration Behavior Study Of Simply Supported Steel Box Girder With Prestressed Tendons

The existence of prestress can not only influence the static effects of structures but also the dynamic effects of structures. The influence of prestress on static effects of structures already had reasonable conclusion. It is necessary to study the influence of prestress on dynamic behavior of structures except static effects of prestressed structures.This paper elaborated domestic and foreign development status of prestressed steel structures and study status of vibration issues of prestressed structures. Then the paper introduced free vibration frequency formula of simply supported beam and simply supported beam with linear prestressed tendons, single broken line prestressed tendons and double broken line prestressed tendons and deduced free vibration frequency formula of simply supported beam with curved prestressed tendons.Combined with text model structure characteristics of Harbin Gongnongbing steel box girder, models of simply supported steel box girder and simply supported steel box girder with prestressed tendons were established by means of finite element analysis software ANSYS and carried on mode analysis to them. The free vibration frequency of text model without prestressed tendons and text model with prestressed tendons were calculated by free vibration frequency calculation formula of simply supported beam and simply supported beam with prestressed tendons. The free vibration frequency formula which this paper deduced and the finite element models were verified well by comparing free vibration frequency results of theoretical calculation, finite element analysis and model text.The influence of prestress on vibration behavior of simply supported steel box girder were analyzed by finite element method. And then the article analyzed the influence of the prestress value in cables, the cable sectional area, the cable anchor position and the cable layouts on vibration behavior of simply supported steel box girder with prestressed tendons by finite element and theoretical calculation method.