预应力混凝土箱梁桥竖向预应力孔道对腹板截面

以两片安装竖向筋试验简支梁为基础，进行了预应力混凝土箱梁桥竖向预应力孔道对腹板截面削弱的研究，试验表明在不灌浆情况下梁开裂荷载提前，箍筋应力、混凝土表面主拉应增加明显，同时对试验梁进行了有限元分析，试验结果与有限元分析一致。研究表明加强竖向预应力灌浆质量的检测与管理对防止预应力混凝土箱梁桥的开裂有重要意义，同时为分析这类桥的开裂原因提供了理论与试验依据。

Weakening effect of vertical prestress ducts on web sections in prestressed concrete box girder bridges

Based on experimental study result of two simply supported beams, which were prestressed by vertical tendons, the research on the weakening effect of vertical prestress ducts on web sections of prestressed concrete box girder was carried out. The test result shows that in the condition without grouting into the ducts, the cracking load is evidently lower than that with full grouting, and stirrup stress and principal tension stress at the surface of concrete will increase obviously. Meanwhile, the finite element analysis has been done to the test beams. The research is consistent with the analysis of finite element. The research tells that strengthening the detection and management for the vertical prestress grouting quality have an important meaning to prevent cracking of the prestressed concrete box girder bridge and provide one theoretical and testing basis for analyzing the cracking reason of such bridges.