Study On Measurement Of Cable Tension By Frequency Method

Measurement of cable tension is a important content in construction control of cable stayed bridge, which has a key effection to control structure internal force and finished bridge states.Taking the Jinsha River bridge as a example, researching on the stayed cable's force by the finite element method and the analytical method is carried. It is the finite element method that establishing numerical model, simulating the stayed cable's vibration, calculating the stayed cable's vibration frequency. It is the analytical method that deducing mathematical formula which fits to the known conditions by using basic theory and hypothesis. The equation of string vibration including string's stiffness base on the equation of string vibration is deduced, and be solved by introducing parameters, then the function which betweens cable tension and frequency is got. Vibration equation which includes the effection of damping system based on energy method is analyzed. Then according to the actual shape of stayed cable, the equation which reflects the effection of cable sag is solved, and the semi-empirical formula is present. Modify the semi-empirical formula by comparing it to the results of analysis of finite element method.Meanwhile, those especial problems which only exist in the parallel strand stayed cable such as the discretness of stayed cable, inhomogeneity of stayed cable, the effection of HDPE pipe are analyzed. Get the suitable formula which can reflect the properties of parallel strand stayed cable through conclusion analytical data. This function has a guidance meaning to this bridge, and provide ssome suggestion to similar projects.