大跨度复杂结构桥梁施工全过程结构空间受力特性研究

Research on the Space Stress-distribution Characteristics of Long-span and Complex Structure Bridge during the Whole Construction Process

研究目的:通过建立施工全过程时效和路效分析的三维非线性模型,对大跨度V形连续刚构拱组合结构桥的施工全过程空间受力特性进行研究,解决以往的桥梁设计和施工监控采用的计算方法不能有效分析混凝土箱梁的剪力滞、扭转和畸变等引起的截面应力分布不均匀问题。研究结论:分析了大跨度V形连续刚构拱组合结构桥施工全过程主梁截面顶板纵向正应力、横向压应力、腹板剪应力等截面空间应力分布和变化规律,其表现在:主梁截面顶板纵向正应力沿横向分布呈显著的不均匀性,剪力滞效应明显,与初等梁理论的预测值相异;主梁横向压应力普遍不大,且顶板应力分布不均匀程度大于底板;单箱双室截面梁三腹板剪应力分布连续变化,且中腹板的剪应力略大于边腹板剪应力,整体具有较好的规律性;施工全过程主梁纵向正应力包络线体现了最大拉应力和最大压应力的施工工况,为施工控制提供了理论基础。

Research purposes： By establishing three-dimensional non-linear model with aging and road construction efficiency analysis for the whole construction process,the research is done on the space stress-distribution characteristics of large-span V-shaped continuous rigid frame arch composite structure bridge during the whole construction process to solve the problem of uneven stress-distribution on the cross-section due to the shear lag and distortion of concrete box girder with the previous calculation method for bridge design and construction monitoring.Research conclusions：The analyses are made for the space stress-distribution and spatial variation of the longitudinal normal stress and transverse compressive stress on the roof and the shear stress on the sternum of large-span V-shaped continuous rigid frame arch composite structure bridge and their change regulations during the whole construction process.From the analyses the following conclusions are drawn： Firstly,the longitudinal normal stress on the roof of main girder is distributed along the transverse direction with unevenness,and the shear lag effects of the stress are obvious,which is different from the predicted results with elementary beam theory.Secondly,the transverse compressive stress of the main girder is not big and the uneven level of stress distribution on the roof is more than that on the floor.Thirdly,the shear stress distribution on the tri-web of single-box and double-booth section girder continuously changes and the shear stress on center web is slightly greater than that on the side web with good regulation.Lastly,during construction the envelope of longitudinal normal stress reflects the working condition with the maximum tensile stress and maximum compressive stress and this provides a theoretical basis for construction control.