支架现浇刚性系杆拱桥的吊杆施工张拉力确定方法

摘要

In view of the fact that the calculation and adjustment of the hanger cable forces in the construction of the hanger tensioning for the rigid tied arch bridges cast in situ on supports are difficult ,a rigid tied arch bridge cast in situ on staging w as taken as the research object and a kind of the new determination method for the construction tensioning forces of the hangers was put for‐ward .In the method ,the concept of the off‐support coefficients was given first .With reference to the hanger cable force influence matrices of the calculation models with and with no supports and through the approximate calculation ,the cable force influence matrices in the process that the main girder of the bridge separated from the staging were obtained .Then the forward iteration calcula‐tion was implemented ,using the obtained cable force influence matrices so that the construction tensioning forces of the hangers of the bridge could be determined .To verify the feasibility and ap‐plicability of the determination method ,the method was applied to the construction of the hanger tensioning for the main bridge of the Second Enjiang River Bridge (with span arrangement 65 m+65 m) in Jishui County ,Jiangxi Province and with the method ,the construction tensioning forces of the hangers of the bridge tensioned for two times were obtained and the hanger forces after the hanger tensioning was completed were measured .The results show that the determination method can be used to accurately calculate the construction tensioning forces of the hangers before the staging of the main girder is removed .T he calculation convergence is fast and the convergence is effective .The errors between the measured and target cable forces of the different hangers are basically controlled in the ranges allowed in the codes .When the method is used for determina‐tion of the construction tensioning forces of the hangers in the hanger tensioning ,sound tensio‐ning effect of the hangers can be expected .%针对支架现浇刚性系杆拱桥在吊杆张拉施工过程的吊杆索力计算和调整难题，以采用满堂支架现浇施工的刚性系杆拱桥为研究对象，提出一种新的吊杆施工张拉力确定方法。在该方法中，首先提出了脱架系数的概念，并结合有支架计算模型和无支架计算模型的索力影响矩阵，近似计算得到主梁脱离支架过程中的索力影响矩阵，而后利用该索力影响矩阵进行正装迭代运算，以确定吊杆施工张拉力。为验证该方法的可行性与适用性，将该法应用于江西省吉水县恩江二桥主桥（跨度65 m＋65 m ）的吊杆张拉施工中，利用该法计算得到了该桥吊杆2次张拉的施工张拉力，并对吊杆张拉施工结束后的索力进行了测量。结果表明：该方法能较准确地计算主梁支架拆除前的吊杆施工张拉力，收敛速度较快，且收敛效果好；各吊杆的实测索力与目标索力间的误差基本控制在规范允许范围之内，利用该法确定的吊杆施工张拉力来进行吊杆张拉施工，张拉效果良好。