考虑不平衡力矩作用下的转体球铰设计方法研究

Research on Rotational Spherical Hinge Design Method Considering Unbalanced Moments

针对平转法转体桥梁转体球铰常规设计法忽略不平衡力矩造成球铰设计安全储备不足或后期转体困难等问题,提出考虑不平衡力矩作用下的转体球铰设计方法,以成都某T构转体桥为背景进行研究。采用MIDAS FEA软件建立转体球铰部分有限元模型,分析钢制球铰半径改变对结构受力的影响规律;然后推导不平衡状态下球铰应力计算公式,通过转体结构的受力关系,根据撑脚是否着地的设计目标,按结构对称与非对称,给出球铰半径的确定方法,进而确定启动力矩等其他设计参数;最后结合转体桥梁工程实例验证该方法的适用性及准确性。结果表明:考虑不平衡力矩作用下的球铰设计方法适用于当前不同转体工程实例,其适用范围更广、安全性更好;转体球铰设计时应预先考虑不平衡力矩对球铰设计的影响。

In the conventional design of the spherical hinge that serves the rotation of a structure,the unbalanced moments are not given enough concern,as a result,the design safety margin of the structure is not sufficient and the spherical hinge could not rotate smoothly after the completion of the bridge.In this paper,a spherical hinge design method that takes into account the effects of unbalanced moments is presented.Based on a T-frame bridge that is constructed by rotation method,a finite element model of the spherical hinge was built up in MIDAS FEA,to analyze the influence of hinge radius change on the load bearing behavior of the bridge structure.The stress calculation formula for the spherical hinge in unbalanced state was derived.The load bearing behavior of the structure rotated was investigated and the method to determine the radius of the spherical hinge was presented,in which the landing of the supporting stand was final target,and the balanced and unbalanced configuration of the structure were taken into account in the calculation.Subsequently,the starting moments and other design parameters were confirmed.Case bridges were cited to verify if the method presented was applicable and able to generate correct results.It is shown that the spherical hinge design method which takes into account the unbalanced moments is applicable to the selected case bridges,which has potential applications in the future and can ensure higher level of security.It is suggested that the influence of unbalanced moments be considered before the commencement of the spherical hinge design.