节段拼装钢结构主梁弯曲性能试验研究

Research on Bending Properties of Steel Girder Based on Segmental Construction Technique

基于钢结构的优良特性,提出了一种节段拼装且腹板开孔的钢结构主梁——圆环腹梁。基于铁木辛柯梁理论,通过推导该主梁的抗弯和抗剪刚度,得到了横向荷载作用下的挠度计算方法。为研究该主梁的弯曲性能,按照JTG D64—2015《公路钢结构桥梁设计规范》要求,加工制作了2根缩尺模型试件,分别进行三分点加载和跨中单点加载试验。基于有限元软件ABAQUS建立了试件的非线性分析模型,并将模拟结果与试验结果进行了对比。研究表明:1)提出的挠度计算方法可有效计算弹性变形阶段的主梁竖向变形量;2)三分点加载试验中,结构顶板边缘易受压失稳,需进行加固;3)单点加载试验中,主梁达到屈服荷载后,顶板发生受压屈曲,顶板和底板的应力水平接近Q235的屈服强度。

According to the excellent characteristics of steel structure,a kinds of steel girder with segmental assembly and web opening,truss-ring girder,was presented.Based on the theory of Timoshenko beam,the deflection of truss-ring girder under vertical load was obtained by deriving the bending and shear stiffness of the girder.In order to study the bending properties of the girder,two scale model specimens were fabricated according to the requirements of Specifications for Design of Highway Steel Bridge(JTG D64—2015),which were carried out by four-point loading and three-point loading tests,respectively.Two nonlinear analysis models of the specimens were established based on the finite element software ABAQUS,whose results were compared with the test results.The results showed that:1) the proposed deflection calculation method could effectively calculate the deflection of the girder in the elastic deformation stage;2) in four-point loading test,the edge of the top deck was prone to lose stability under pressure,which needed to be reinforced;3) in three-point loading test,the girder reached the yield load,and the compression buckling of the top deck occurred,and the stress level of the top deck and bottom deck were close to the yield strength of Q235.