基于乌龙江大桥的预应力配筋方案优化研究

Optimization of Prestressed Reinforcement Scheme of Wu Long River Bridge

多跨度连续箱梁桥采用水平向直线预应力筋和竖向预应力筋相结合,取消下弯筋,施工方便;但竖向预应力筋较短,预应力损失较大,主拉应力实际上不能完全抵消,腹板斜截面容易出现裂缝,影响结构的正常使用.曲线预应力筋较长,后期预应力损失较小.乌龙江大桥采用了主要依靠曲线预应力抵抗主拉应力和竖向预应力作为安全储备的配筋方式,大桥实测和分析表明其有效预应力可靠性高,在设计中应加以推广.

This paper uses a large span continuous box girder bridge which is combined with linear and verticalprestressed tendons and cancels the recurved ribs which is convenient for construction. But because of the shortervertical tendons and the prestressed greater losses,the main tensile stress can not be actually fully offsetted and theweb oblique section prone to cracks in abnormal structure using. We find the curve prestressed tendons are longerand the late loss of prestressed is less. Wulong River Bridge mainly takes the curved prestressed resistanceprincipal tensile stress and vertical prestressed reinforcement approach as a safety reserve which shows effectiveprestressed high reliability in measurement and analysis. The approach should be promoted in the design .