预应力混凝土现浇箱梁分联结构分析

Analysis of cast-in-place prestressed concrete box girders span division

通过20 m,25 m,30 m跨径分别从3孔一联到6孔一联采用满堂支架施工方案的结构分析计算,根据各跨径组合中钢束联长中点截面处其有效应力数据的对比分析结果,得出以上3种跨径中跨径相对越大、跨数越多,联长中点截面处钢绞线的预应力损失越大的结论。计算结果表明:25 m,30 m跨径超过4孔一联采用满堂支架的施工方案已达不到经济、合理的设计理念要求,若设计需采用此种跨径组合的分联设计时就需要采用逐孔浇筑等其他施工方案,以达到预应力充分发挥其材料性能的目的。

By structural analysis of 20 m,25 m,30 m span bridges from 3 to 6 span combinations with the construction methods of full framing,according to the comparison of effective stress at midpoint for the bridge with different span combinations,it is found that the prestress loss at the midpoint of the bridge is greater when the span is relatively larger and the number of span is more.The results show that： 25 m,30 m span bridge of more than four spans with full framing construction method is not a cost-effective design,if such a design is required,it needs to adopt span by span construction method or other construction plans to achieve the prestressed material properties of its full purpose.