大跨变截面波形钢腹板箱梁横向受力分析

为研究大跨变截面波形钢腹板预应力混凝土（PC）组合箱梁顶板在车轮局部荷载作用下的横向受力问题，结合2座桥例，分别建立全桥实体有限元模型；选择纵向3个典型截面，建立与之匹配和考虑有效分布宽度的平面框架模型；依据实体模型中顶板控制截面的横向应力影响线进行空间实体模型和平面框架模型的横向最不利加载，获得控制截面的最大横向拉应力及其沿纵向的变化规律，并对比了2种模型的计算结果。结果表明:对于顶板悬臂根部截面和腹板内侧截面，框架法与实体有限元法计算结果吻合良好；对于顶板跨中截面，腹板间距较大时，框架法的计算值偏于保守，设计中需对框架法的计算值进行适当折减；随着加载位置由跨中向支点移动，顶板跨中截面的横向应力峰值逐渐减小，悬臂根部截面和腹板内侧截面的横向应力峰值有增大趋势；有无横隔板对桥面板的横向受力影响很小，顶板跨中截面的横向应力值随波形钢腹板线刚度的增加线性减小。

Analysis on Transverse Force of Large Span Variable Cross-section Box Girder with Corrugated Steel Webs

In order to study the transverse force of the roof of large span variable cross section prestressed concrete （PC） composite box girder with corrugated steel webs under the local load of wheel, combined with two bridge examples, the solid finite element models of the two whole bridges were established. Three longitudinal typical cross sections were selected, the matched plane frame models considering the effective distribution width were established. According to the influence lines of transverse stress of the roof control sections in the solid finite element models, the transverse most unfavorable loadings of the spatial entity model and the plane frame model were applied. The maximum transverse tensile stress of control sections and the variation law along the longitudinal direction were obtained, and the calculation results of the two models were compared. The results show that the frame method is in good agreement with the solid finite element method for root sections of roof cantilever plates and inner sections of webs. While for mid span sections of roofs, the calculated results of frame method are conservative when the web space is larger, and the calculated results of the frame method should be properly reduced in design. With the moving of load position from mid span to support, the peak transverse stresses of mid span sections of roof decrease gradually, while the peak transverse stresses of root sections of cantilever plates and inner sections of webs have a tendency to increase. The diaphragms have little impact on the transverse force of the bridge deck. The transverse stress values of mid span sections of roofs decrease linearly with the increase of line stiffness of corrugated steel webs.