Study On Cable Force Calculation Method Subjected To Control Objective Based On Main Arch Displacement

Recent years, long-span arch bridge has been rapidly developed,in China.The installation method of the main arch is mainly cable-stayed suspension method,except a small number remain using body rotating method and integral lifting method.The calculation of cable force and camber capacity is the key to the cable erection without trestle in construction control.There are many calculation method about cable force value and pre-camber capacity for cable hoisting method,but a problem appears when close the arch after releasing cable;At the same time,when set up the finite element model,many neglect the impact of tower,that results in the calculation results have great difference with the actual.Therefor,the thesis propose a new cable force calculation method based on the goal of bare arch deformation,and set up finite element model including arch rib,tower,cable and back cable,in order to calculate the cable force and camber capacity.The main content is as follows:1. Analyse the problem of previous calculation methods, introduce the reason when close arch after releasing cable,and put forward the method of elevating arch rib segment by negative camber on this basis.2. Propose a cable force calculation method based on the goal of bare arch deformation by overall installation and sub-installation of arch rib.3. Research the reason of horizontal deviation in the multi-ribbed arch bridge, obtain the results by analysis that elevation difference of arch rib will cause arch axis horizontal deviation,and deduce the geometric relationship between elevation difference of arch rib and horizontal deviation of arch axis.4. Analyse the effects of tower deduction to the elevation of arch rib segment, and derive the formula about tower deduction to the elevation of arch rib segment.5. Based on the ANSYS APDL language,write program about construction control of long span concrete-filled steel tubular arch bridge,carry out the cable force and camber capacity calculation for concrete-filled steel tubular arch bridge—Xiaohe Bridge and the Xinlongmen Bridge.Practice shows that the method proposed and the program are right,the measured cable value and theoretical value are in good agreement,arch axis after releasing cable is basically same with bare arch deformation,overcome the appearance of saddle-shaped arch rib.