单箱双室箱梁对称弯曲时的局部扭转效应

发布时间：2018-06-26 22:08

本文选题：单箱双室箱梁 + 竖向弯曲　；参考：《建筑结构学报》2017年07期

【摘要】：为研究单箱双室箱梁在对称竖向荷载作用下的受力特征,基于横截面的荷载等效原理与荷载分解,分析了单箱双室箱梁对称弯曲时的局部扭转效应。基于截面的剪力流平衡和箱室受力分解,得到了局部扭转的等效荷载及应力计算式。通过与有机玻璃模型试验和有限元模拟结果的对比,验证了局部扭转效应计算式的正确性,并获得了单箱双室简支箱梁的局部扭转效应下的应力分布规律。研究表明,单箱双室箱梁在仅中腹板作用竖向荷载及两边腹板作用相等竖向荷载时,均存在纵向弯曲和局部扭转的组合变形模式。局部扭转由约束扭转、畸变和横向弯曲效应组成,在截面引起纵向应力和横向应力。局部扭转效应的理论计算结果与模型试验和板壳有限元分析结果吻合良好,表明基于截面剪力流等效的局部扭转荷载求解方法对双室箱梁是适用的;单箱双室箱梁的局部扭转效应在荷载作用点附近截面最为突出,截面上、下缘纵向应力和横向应力以中腹板为拐点呈折线分布,其应力分布和大小与荷载在横截面上作用的部位紧密关联;对算例箱梁,局部扭转效应产生的纵向应力可达初等梁弯曲应力的25%。
[Abstract]:In order to study the stress characteristics of single box and double chamber box girder under symmetrical vertical load, the local torsional effect of symmetrical bending of single box and double chamber box girder is analyzed based on the principle of load equivalence and load decomposition of cross section. The equivalent loads and stresses of local torsion are obtained based on the shear flow equilibrium of the section and the stress decomposition of the chamber. By comparing with the results of model test and finite element simulation of organic glass, the correctness of the local torsional effect is verified, and the stress distribution of single-box and double-chamber simply supported box girder is obtained under the local torsional effect. The results show that there are combined deformation modes of longitudinal bending and local torsion for single box and double chamber box girder under only vertical load on the middle web and equal vertical load on both sides of the web. Local torsion consists of confined torsion, distortion and transverse bending effect, which causes longitudinal and transverse stresses in the cross section. The theoretical calculation results of local torsion effect are in good agreement with the model test and the finite element analysis of plates and shells. It shows that the local torsional load solution method based on the equivalent cross-section shear flow is applicable to the double-chamber box girder. The local torsional effect of single box and double chamber box girder is the most prominent in the section near the load acting point. On the section, the longitudinal stress and transverse stress of the lower edge of the box girder are distributed in a broken line at the inflection point of the middle web plate. The stress distribution and magnitude are closely related to the position of the load acting on the cross section, and the longitudinal stress due to the local torsional effect can reach 25 parts of the bending stress of the elementary beam for example box girder.
【作者单位】：兰州交通大学甘肃省道路桥梁与地下工程重点实验室;广州铁路集团公司株洲高铁工务段;
【基金】：国家自然科学基金项目(51368031) 甘肃省基础研究创新群体项目(1506RJIA029) 兰州交通大学优秀平台项目(201601)
【分类号】：U441

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