Theory Of Tension Identification And Reliability Analysis Of Inclined Cables During Construction

Take the long span bridge of the Yangtze River in Yinbin city as project background , this eassy fouces on tension identification and reliability analysis of cables during construction.The sag curve of the cables under gravity can be emulated by twice parabola through statical analysis.Through calculating, it was feasible that the truth tension of cables can be replaced by tangential tension of cables.Taking the effects of boundary condition, flexural rigidity and sag of a cable into accoun,the governing equation of motion were discretized by finite difference method. The relation between tension of cables and natural vibration frequencies was described by solving eigenvalue problem. Optimization for calculating model was carried out on the foundation of guaranteeing to distinguish precision have raised the efficiency of this method.The accuracy and practicality of finite difference method was verified under the project background .The parameter of tension variety of bridge of the Yangtze River in Yibin was given ,it was discribed by sign K T,it does not refuse normal distridution.This parameter can be used in reference project to estimate error of tensioning force of cablesThe effect of cable parameters on the tension of cable determination is studied. Show as a result, the not accurate parameters of cables taking effece on short cables greater than long cables in tension identification. The influence of length and the line density of the cables for cable-tention identification precision most obvious; flexible mould and inertia take second place; section product and the inclination of the cables were little for demanding the influence of tension identification precision.Finited element mothod analysis has carried out on the background project. Limit state formula for reliability of inclined cable during construction was established and the probabilistic model for the strength of inclined cable was established also.Through the analysis of each different specifications in construction issue to pull the reliability that got tension most unsuccessfully and calculated the reliability index.Sensitivity analysis was carried out to estimate the influence of parameter in the limit state formula, shows as a result, strength of inclined cable influence biggest, cable-tensioning force take second place , the variation of main beam and weight of the suspended-basket has less influence for reliable index.