偏载作用下单箱三室波形钢腹板悬臂梁的力学特性

Mechanical Properties of Single Box Three-cell Cantilever Girder with Corrugated Steel Webs Under Eccentric Loading

为了解单箱三室波形钢腹板组合梁悬臂施工状态下的扭转效应,设计制作了1片单箱三室波形钢腹板双悬臂梁模型,研究了该类悬臂梁在偏载作用下梁体变形、截面翘曲应力、翘曲应变及波形钢腹板附加剪应力等力学性能,并以国内某单箱三室波形钢组合梁桥为背景,采用有限元模型分析了不同工况下最大悬臂施工阶段单箱三室波形钢腹板截面的力学性能。结果表明:偏载作用下,波形钢腹板上纵向翘曲应变明显小于混凝土顶底板,计算时可忽略波形钢腹板纵向翘曲应力的影响;截面最大翘曲正应力出现在混凝土底板角点处,钢腹板附加剪应力沿梁高方向呈均匀分布,且加载侧边腹板附加应力值明显大于中腹板;实际工程中,考虑恒载作用时,截面底板翘曲应力约占弯曲应力的20%,故在进行该类桥设计计算时,不可忽略混凝土板翘曲正应力和波形钢腹板附加剪应力的影响。

To investigate the torsion effect of single box three-cell composite girder with corrugated steel webs in cantilever state under construction,a double-cantilever beam model of single box three-cell girder with corrugated steel webs was designed and conducted to analyze the mechanical properties,such as deformation,warping stress and strain of the cross-section,additional shear stress of the corrugated steel webs,etc..The results show that the longitudinal warping strain on the corrugated steel webs is obviously smaller than that of the top and bottom concrete flange and the effects of the corrugated steel webs on longitudinal warping stress can be ignored in calculation.The maximum warping normal stress occurs at the corner of the bottom concrete flange.The additional shear stress of corrugated steel webs is uniformly distribution along the beam height direction,the additional shear stress of the side web is obviously larger than that of the middle web.However,in the practical engineering,the warping normal stress of the bottom concrete flange is about 20%of the bending normal stress.Therefore,the warping normal stress of the concrete slabs and the additional shear stress of the corrugated steel webs cannot be ignored in calculation of this bridge design.