PC箱梁桥底板横向应力计算方法及试验

Analytical and experimental study on calculation for transverse stress of bottom slab of PC box-girder

为了解决预应力变截面箱梁桥合龙段底板横向应力难以准确计算的问题,提出了一种能够相对准确计算合龙段附近径向力大小的方法,并在弹性支承框架法和刚性支承框架法的基础上,发展了一种以腹板抗拉刚度近似弹性支承刚度的"近似弹性支承半框架法";对一座单箱多室箱梁桥合龙段底板在不同预应力索张拉工况下的横向应变进行了实桥测试,并利用三维有限元程序进行了数值模拟计算。结果表明,理论计算、实桥测试和有限元模拟结果三者之间吻合较好,说明提出的计算方法能够有效用于此类箱梁桥合龙段底板横向应力的计算。

In order to deal with the problem that it is difficult to calculate the transverse stress of bottom slab of closure segment of PC box-girder with varying-depth section accurately,a formula to compute the radial force resulted from the curvilinear location of closure cables in bottom slab was deduced,and a new method was developed based on elastic-supporting frame method（EFM） and rigid-supporting frame method（RFM）.The elastic-supporting rigidity equals to the tensile rigidity of the web approximately in this new method which is called approximate elastic-supporting half frame method（AEHFM）.Subsequently,the field test of transverse strain of bottom slab of closure segment of a PC box-girder bridge with single box and multi-cell was conducted,and 3D finite element simulation was performed.The results obtained from analytical method,test and finite element simulation show a good agreement which verify the analytical method is feasible.