平转连续梁桥主梁现浇施工中的摩阻效应

采用平转施工的连续梁桥,其转体梁段一般使用支架现浇的方式制作。在转体梁段分段长度较长的情况下,现浇梁体和模板接触面会产生较大的摩阻力和切向黏结应力,阻碍梁体的自由变形,因而增大预应力箱梁的应力损失。采用有限元分析软件,分析了现浇梁与底模支架之间的摩阻系数和模板约束情况,计算了预应力筋张拉时主梁最大悬臂状态各单元应力。结果表明:一定情况下此摩阻和约束效应对梁体有效预应力的影响是不能忽视的。

Friction Effect of Girder of Horizontal Swing Continuous Beam Bridge in Cast-in-Site Construction

The continuous beam bridge constructed with the technology of horizontal swing usually builds its’ spin beam section in a way of scaffold in-site.When the spin beam section is too long,a great frictional force and tangential cohesive force will occur in the contact surface between the casting beam body and shuttering,which will hinder the free deformation of beam,as a result,the stress losses of pre-stressed box beam will be increased.Using finite element analysis software,the frictional coefficients between the casting beam and the holder of bottom shuttering are analyzed,and the girder element stress of the biggest cantilever state is calculated when the pre-stressed reinforced steel is stretched.The result indicates that the influence of the friction effect and tangential cohesive effect on the pre-stress of beam body can’t be ignored in some cases.