Study On The Key Problems Of Tension Control Of Suspension Bridge’ Anchor Span

As an important process of suspension bridge construction, the quality of anchor spans tension control need to meet the engineering demand. Based on the project of Yangtze River bridge Yichang Miaozui, this thesis mainly study the cable erection, measurement, adjustment and other aspects according to the characteristics of the suspension bridge anchor spans. The main research is as follows:(1) A new suspension bridge anchor spans adjustment method was proposed by analyzing the existing anchor span cable shares erection method, simplifying strand friction calculation method, and considering the frame cable and splay saddle temporary constraint release time. This method adjusts the convenient and dispenses temperature of strand adjustment caused by the influence of avoid strands slide hazards.(2) A simplified model and the calculation formula of the anchor beam in the state of tension and complete installation state were proposed by analyzing the cable vibration theory. The problem of accurate computation in different anchor beam states was solved and the deduced formulas can be applied to the accurate calculation of different cables.(3) The effect of follow-up cable strand erection on the previous set strands of frequency-cable force in calculation formula was studied. According to the measured data, the reason and the range of the effect were analyzed and the corrected formula was proposed. The problem of the cable force measurement and accurately control were solved as well.(4) The effect of cable strands length change caused by the load and boundary conditions change on the calculation formula was studied. According to the measured data, a conclusion was drew that the change of cable force calculation formula is little and it can still be applied to the accurate calculation.(5) According to the different strands of the adjustment method and splay saddle angle adjustment of the actual situation, the influence of plate thickness on the adjustment of cable force was considered, and a new adjustment method of cable force was put forward to make the cable force adjustment work faster and more efficient. According to the engineering practice, the application scope of each cable force adjustment method is analyzed in order to meet the requirements of the cable force adjustment under different construction conditions.In this thesis, the test and adjustment method of cable strand has achieved good results based on the verification of the actual data. The research results can be applied to the construction control of the anchor span of the late suspension bridge.