混凝土连续箱梁高宽比对竖向挠度的影响

Influence of Aspect Ratio of Concrete Continuous Box Girder on Vertical Deflection

以宝兰客专某60m单室连续箱梁为算例,利用有限元软件建立承受满跨均布荷载作用、中跨固定和边跨铰接的混凝土连续梁的有限元模型,对比分析了不同截面高宽比条件下考虑剪力滞效应连续箱梁的竖向挠曲分布特征,探讨了桥梁保证安全、经济性和适用性条件,箱梁最优宽跨比在设计取值的问题。结果表明:(1)满跨均布荷载作用于混凝土单室连续箱型截面梁,随着截面高宽比的增大,跨中位置竖向挠度随着高宽比增大而减小,高宽比增大17%,跨中竖向最大挠度减小了44.3%。(2)箱梁的挠度与高宽比变化呈相反的趋势,在满足箱梁安全、大跨度和经济性的要求的前提下,今后大跨度连续箱梁设计中可优先考虑较小的截面高宽比,克服了规范限制高宽比的单一、保守做法。

Taking a 60m single cell continuous box girder of Baoji-Lanzhou high-speed railway as an example,this paper establishes a finite element model of the continuous concrete girder with full span,middle span and side span by using the finite element software,compares and analyzes the vertical deflection distribution characteristics of the continuous box girder considering shear lag effect under different section height width ratio,discusses the bridge safety,economy and stability and the optimal width span ratio of box girder is determined in design.