Study On Accurate Control Technology Of Cable Hoisting With Less Buckle Cable Of CFST Arch Bridge

CFST arch bridges have been developing rapidly in China due to their advantages such as beautiful shape,strong crossing ability,good economy,and the use of empty steel tubes as templates during core concrete construction.So far,most of the CFST arch bridges built in China have been constructed by cable hoisting and cable-stayed bucking method,usually sets a pair of buckle anchor cables in each arch rib segment.With the increase of the span of the CFST arch bridge,more and more arch rib segments must be divided in order to control the segment lifting weight reasonably,so more buckle anchor cables need to be arranged.Therefore,this dissertation,based on the main span of the458 m Qianwei Minjiang River Bridge in Sichuan Province,studies the construction and control measures of the cable hoisting with less cable buckle method.The main research contents are as follows:(1)In view of the problems of the traditional cable force optimization analysis method,such as many constraints,complicated calculations,and large fluctuations in the pre-lift value and cable force value,based on optimization theory,the influence matrix of the prelift value of the arch rib segment is introduced,the objective function and constraints are improved,and the buckle cable force optimization algorithm based on the influence matrix and buckle cable force optimization algorithm based on the unstressed state method are proposed,which realizes the dual control of the alignment of the arch rib during the lifting stage and after removing the cable.(2)The buckle cable force and the pre-lift value of the arch rib segment were calculated for cable hoisting full buckle cable and less cable buckle construction schemes,respectively.Based on these calculations,the advantages and disadvantages of the two construction schemes were compared and analyzed in terms of the forces on the buckle tower and anchorage,the arch rib alignment and stress,and the amount of material used for buckle anchor cables.(3)Taking the construction process of cable hoisting with less cable buckle of Qianwei Minjiang River Bridge in Sichuan Province as the research object,the influences of temperature changes,tower offset,and installation error on the arch rib alignment are analyzed.At the same time,the corresponding construction control measures are proposed in order to realize the high precision control of the construction of cable hoisting with less cable buckle.(4)This dissertation studies the influence of the two conversion modes of temporary and formal cable on the alignment and stress of the arch rib in the construction of cable hoisting with less buckle cable method and determines the reasonable conversion mode.In view of the possible alignment error during the construction process of cable hoisting with less buckle cable method,the arch rib alignment adjustment method based on the influence matrix for less buckle cable method is proposed to solve the adjustment problem of arch rib alignment error during the construction of cable hoisting with less cable buckle method.(5)The construction scheme of cable hoisting with less buckle cable and its construction control measures were applied to the arch rib lifting construction of Qianwei Minjiang River Bridge in Sichuan Province.The cable force and arch rib alignment during the construction of the arch ribs lifting were measured,and the measured data and theoretical calculation results were compared and analyzed to verify the feasibility of the construction method and its construction control measures for cable hoisting with less buckle cable.At the same time,the high precision control for the construction of cable hoisting with less buckle cable method was realized.