酉水大桥大跨度连续箱梁桥斜交高墩几何非线性效应与稳定性分析

High Skew Pier Geometric Nonlinear Effect and Buckling Analysis of Youshui Large Span Continuous Box Girder Bridge

以湖南省张花高速公路酉水大桥(80 m+145 m+80 m)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ANSYS软件建立主桥斜交高墩的三维实体模型,分析了斜交高墩几何非线性效应下的变形、应力及多重非线性作用下的屈曲问题,并且对比分析了不同斜交角度情况下,桥墩非线性屈曲临界荷载的变化情况。分析结果表明:桥墩在考虑几何非线性条件下的整体变形、应力的绝对值都呈增大趋势,墩顶位移增大3.36%,最大拉应力增大3.62%,压应力减小4.27%,可供斜交高墩受力计算分析参考;桥墩特征值屈曲荷载临界值在几何非线性下比线性解小,在考虑材料、几何双重非线性效应下远小于仅考虑几何非线性效应及线性解,此结论对高桥墩几何非线性条件下承载力分析有重要参考意义;斜交角度从0°到90°变化,桥墩的非线性屈曲临界荷载由大变小再变大,在45°时出现极小值,对斜交高墩桥梁的斜交角度设计有重要指导意义。

In this paper, on the background of Youshui bridge, a 80 m ＋ 145 m ＋ 80 in high skew pier large span cantilever casting prestressed concrete box girder continuous bridge of Zhanghua highway in Hunan province, a three-dimensional solid model of the main pier was established by use of ANSYS Software, analysis of deformation and stress of the pier in geometric nonlinear effect and buckling prob- lems of the pier under the action of multiple nonlinear effect were carried out, and a comparative analysis of pier nonlinear buckling critical load on the condition of different skew angles was conducted also. A- nalysis results demonstrate that ： the absolute value of the whole deformation and stress of the pier tend to increase under the consideration of geometric nonlinear conditions, deformation of top pier increases by 3.36% , maximum tensile stress increases by 3.62% , compressive stress reduces by 4.27% , which can be for high skew pier force calculation and analysis reference; the eigenvalue buckling load critical value of the pier in the geometric nonlinearity is smaller than the linear solution, and in considering the materi- al and geometric dual nonlinear effect it is much smaller than that of only considering geometric nonlinear effect and the linear solution, which makes important referential significance for analysis of high pier＇ s bearing capacity under geometric nonlinear condition; nonlinear buckling critical load of the pier changes from large to small and from small to large, and to the minimum in 45° with the skew angle varying from O°to 90°, which makes important guiding significance for the design of skew angle of high skew pierbridge.