正交异性钢桥面板轮载横向效应的解析分析方法

Analytical method for transverse wheel load local effect of orthotropic steel bridge deck

在分析正交异性钢桥面板构造特点的基础上,将轮载影响范围内的桥面板简化为弹性支撑的平面框架,建立了正交异性钢桥面轮载横向效应的解析分析模型,推导了纵肋弹性支撑刚度和车轮荷载集度等效计算方法,提出了桥面板与U肋交接位置处横向弯曲应力的解析公式,讨论并明确了影响桥面板横向弯曲应力峰值的关键敏感影响因素,并以某钢箱梁为例证明了本文算法的合理性。研究发现,本文方法计算得到桥面板与U肋相交位置的横向应力值与有限元结果相差不超过10%,证实了本文算法的正确性,也为正交异性钢桥面的初步设计提供了极大的方便;正交异性钢桥面板的横向轮载应力随U肋厚度和高度增加而增大,但随顶板厚度和横隔板间距增大而减小;相对而言,顶板内横向拉应力受顶板厚度的影响最为显著,对腹板倾角和U肋腹板厚度的变化并不敏感。

Structural characteristics of an orthotropic steel bridge deck were analyzed to simplify the analytical model for an orthotropic deck under local wheel loads.The specific sphere orthotropic deck affected by wheel loads were simplified to an elastic-supported frame model, which was proposed to analyze the local mechanical effects of an orthotropic deck around the wheel load.After derivation of the elastic support stiffness and effective load density, an analytical solution for the transverse bending stress in the top plate of the orthotropic deck was presented.Subsequently, the sensitive factors affecting the bending stress in the orthotropic deck were discussed and identified.A box girder bridge was taken as an example to confirm the proposed theoretical solution of local stress under the wheel load.The analysis results show that the discrepancy between the transverse stress values calculated by this analytical method and the finite element method are no more than 10%,which indicates that this proposed method is accurate and can be applied in the preliminary design of an orthotropic steel bridge deck conveniently.It can also be found out that the transverse stress in the top plate near the web of U-ribs increases with the thickness and height of U-rib increasing, but decreases with the thickness of top-plate and the space between two adjacent diaphragms increasing.Besides, the tensile stress in the bridge deck is most significantly affected by the thickness of the roof, but is not sensitive to the changes of the web angle and thickness of the U-rib.