斜交墩截面刚度与弯曲正应力

斜交墩与正交墩受力的不同主要体现在截面刚度与弯曲正应力,通过理论分析得出斜交墩顺桥向截面刚度相对于正交墩增大,并推导了采用主惯性矩、斜交角和主轴坐标系坐标表示的斜交墩弯曲正应力公式,得到了在顺桥向弯矩作用下斜交墩截面中性轴的位置与斜交角的关系。通过对某实桥的斜交墩进行截面惯性矩计算,建立有限元模型计算弯曲正应力,对研究结论进行了验证。研究结果表明：主轴坐标系任意坐标点的弯曲正应力随着斜交角度变化而变化,且存在极值,该点应力极值对应的斜交角度仅与该点的主轴坐标系纵横坐标比值有关;矩形斜交墩（包括空心墩）顶点处最大弯曲正应力存在最不利的斜交角,并分别得到了矩形实心墩与空心墩角度的解析表达式。

Sectional stiffness and bending normal stress of oblique pier

The differences between oblique pier’s stress and orthogonal pier’s stress are mainly embodied in the sectional stiffness and bending normal stress.The enlarge of the oblique pier sectional stiffness along the direction of the bridge relative to the orthogonal pier was found through theoretical analysis.The formula of the oblique pier’s bending normal stress which is expressed by the principal moment of inertia,skew angle,point coordinate of principal axis coordinate system was deduced.The relation of the section neutral axis’s location and the skew angle under the action of bending moment which is along the direction of the bridge was got.Through the calculation of section moment of inertia of a real bridge’s oblique pier,and the establishment of the finite element models for the calculation of bending normal stress,the conclusions were verified.The results show that the bending normal stress of one point in principal axis coordinate system changes with the change of skew angle,and there is an extreme value.The skew angle of this point corresponding to the maximum stress is only relation with the ratio of the x-coordinate to y-coordinate of the point in principal axis coordinate system.The apex of maximum bending stress of rectangular oblique pier(including hollow pier) has the most adverse oblique angle,the angle’s analytical expression of rectangular solid pier and hollow pier are respectively obtained.