PC箱梁桥腹板竖向预应力锚固系统切向刚度的研究

Research on Tangential Stiffness of Anchorage System of Vertical Prestressing Bars in Webs of Prestressed Concrete Box Girder Bridges

为解决PC箱梁桥腹板竖向预应力失效的问题,建立了腹板竖向预应力锚固系统的非协调接触理论模型,利用位势理论和GW(Greenwood-Williamson)随机粗糙表面模型,求解了弹性半空间体在表面力作用下竖向预应力锚固系统的切向静弹性刚度与张拉力的函数关系,在此基础上进行了竖向预应力模型静载试验验证.结果表明:竖向预应力锚固系统的切向刚度随竖向张拉力的增加呈非线性递增.该研究对于竖向预应力锚固系统的单自由度系统动力学模型的建立以及竖向预应力筋张拉力的定量测试具有重要意义,也为纵向预应力检测提供了理论依据.

To solve the problem of vertical prestressing failures in webs of PC box girder bridges, a nonconforming contact model of the anchorage system of vertical prestressing bars in webs is built. The theory of potential and GW（Greenwood-Williamson） random rough surface model is used to get the function relationship of the tangential static elastic stiffness of the anchorage system of vertical prestressing with tensile force in the situation that surface forces act on elastic half-space body. And on the basis of that, a static test of vertical prestressing model is performed for validation. The results show that the tangential stiffness of the anchorage system of vertical prestressing increases nonlinearly with the increase of tensile force. The research is of great meaning to the construction of the single-degree-of-freedom dynamic model of the anchorage system of vertical prestressing, and of great significance to the quantitative test of vertical prestressing. The research also provides theoretical foundation for vertical prestressing test.