单箱三室波形钢腹板悬臂梁扭转与畸变分析及试验研究

为研究单箱三室波形钢腹板箱梁悬臂状态下的扭转与畸变性能,以乌曼斯基第二理论和箱梁理论为基础,考虑了波形钢腹板的褶皱效应对箱梁纵向刚度的影响,推导了单箱三室波形钢腹板悬臂梁扭转与畸变微分方程,并采用初参数法及弹性地基梁比拟法求解了约束扭转和畸变产生的翘曲正应力和剪应力计算式。通过1片单箱三室波形钢腹板双悬臂梁进行了偏载和对称加载试验,验证了扭转与畸变翘曲应力计算公式的正确性。最后,利用推导的理论模型,分析了梁高、箱室宽度及波形钢腹板厚度等参数对偏载作用下单箱三室波形钢腹板组合箱梁截面翘曲应力的影响。研究结果表明:提出的理论计算公式可用于准确计算单箱三室波形钢腹板悬臂梁扭转与畸变效应;悬臂梁翘曲正应力主要由畸变变形引起,而约束扭转主要产生翘曲剪应力,且悬臂梁扭转和畸变产生的翘曲正应力值和剪应力值与弯曲正应力和剪应力的比值较大,因此,单箱三室波形钢腹板悬臂状态下扭转和畸变产生的翘曲正应力和剪应力不可忽略;梁高和箱室宽度对单箱三室波形钢腹板的翘曲应力影响较为显著,波形钢腹板厚度对其几乎没影响。

Analysis and experimental study on torsion and distortion of singlebox three-cell cantilever girder with corrugated steel webs

To study the torsion and distortion performance of single box three-cell girder with corrugated steel webs in cantilever state, the differential equations of torsion and distortion for the girder were derived considering the corrugation effect of corrugated steel webs and based on the second theory of Umanskii and the theory of box girder. Then, the calculations of the warping normal stress and shear stress caused by constrained torsion and distortion were solved by employing the initial parameter method and the elastic foundation beam method respectively. The calculation formulae proposed in this paper were verified by a single box three-cell double cantilever girder with corrugated steel webs under partial loads and symmetrical loads. Finally, for the single box three-cell composite girder with corrugated steel webs under partial load, the effects of parameters such as height, width and thickness of corrugated steel webs on the warping stress were analyzed by the theoretical model. The results show that the torsion and distortion effects of the single box three-cell cantilever girder with corrugated steel webs can be accurately calculated by the theoretical formulas. The warping normal stress of the cantilever beam is mainly caused by the distortion deformation while the warping shear stress is mainly produced by the restrained torsion. The warping normal stress and shear stress caused by the torsion and distortion of the single box three-cell cantilever girder with corrugated steel webs cannot be ignored because the ratio of the warping stress to the bending stress of the cantilever beam is large. The height and width have a significant influence on the warping stress of single box three-cell composite girder with corrugated steel webs, and the thickness of corrugated steel webs has almost no effect.