提高高腹板箱梁竖向预应力压浆畅通度的研究

Research on Improving the Smoothness of Vertical Grouting for Prestressed System of High Web Plate Box Girder

现阶段我国大跨连续箱梁桥普遍采用纵横竖三向预应力体系,其中竖向预应力的使用增强了腹板的抗剪能力,防止裂缝的产生。但在实际施工过程中,竖向预应力常常出现压浆不密实的情况,不能使预应力筋与梁体混凝土牢固粘结为整体,还会引起预应力筋锈蚀,从而影响预应力梁的寿命。本文根据长湾澧水大桥竖向预应力筋施工方案,总结了如何提高竖向预应力孔道压浆畅通度,可为类似工程提供参考。

At present,the three-directional prestressed system is generally adopted in the large span continuous box girder bridge in our country.The use of vertical prestress strengthens the shear ability of the web and prevents the crack.However,in the actual construction process,the vertical prestress is often not compacted by grouting,which not only fails to make the prestressing tendons firmly bond with the beam concrete as a whole,but also causes the corrosion of the prestressing tendons,thus affecting the service life of the prestressed beam.Based on the construction scheme of vertical prestressing tendons of Changwan Lishui Bridge,the author summarized how to improve the smoothness of vertical prestressed duct grouting,which could provide reference for similar projects.