酉水大桥大跨度预应力混凝土连续梁桥斜交高墩盖梁受力特征分析

High Skew Pier Capping Beam Stress Characteristic Analysis of Youshui Large Span Prestressed Concrete Continuous Beam Bridge

以湖南省张花高速公路酉水大桥(80 m+145 m+80 m)斜交高墩大跨度悬臂浇筑预应力混凝土连续箱梁桥为工程背景,运用MIDAS软件建立箱梁整体梁格模型,得出桥墩的最不利荷载组合,在此基础上运用AN-SYS软件建立主桥斜交高墩实体模型,对盖梁在最不利上部荷载作用下的受力特征进行分析。分析计算结果表明,斜交高墩盖梁应力分布特征有别于正交桥墩盖梁,该正八边形盖梁最小压应力产生于支座垫石与盖梁接触面中心处,以垫石为中心向四周逐渐变大;盖梁在两个支座垫石之间的局部区域存在超出混凝土抗拉极限设计值的拉应力,该拉应力产生于盖梁中心上表面处。分析结果对不同于正交桥墩盖梁支点角隅区钢筋的配置有指导意义。

In this paper,on the fiackground of Youshui bridge, a 80 m ＋ 145 m ＋ 80 m high skew pier large span cantilever casting prestressed concrete box girder continuous bridge of Zhanghua highway in Hunan province ,the overall grillage model of box girder was established by use of Midas Software,then the most unfavorable load combinations of piers were obtained. On the basis of above, the capping beam stress characteristic analysis under the most unfavorable upper loads were carried out by use of ANSYS software by establishing a solid model of the main pier. The analysis results show that the Stress Distribu- tion features of skew capping beam are different from that of orthogonal pier capping beam. The minimum compress stress of the regular octagon capping beam occurs in the contact center place of bearing pad stone and capping beam, and gradually became larger around the pad stone to the surrounding; there ex- ists tensile stress beyond the ultimate tensile design value of concrete in the local area between two bear- ing pad stones and the tensile stress occurs at the center surface of the capping beam. The results can make important guiding significance for arrangement of bars in the pivot corners of the capping beam that is different from orthogonal capping beam.