考虑整体节点刚域模拟影响的钢桁梁力学效应分析

Analysis of Mechanical Effect of Steel Truss Girder Considering Influences of Rigid Zone Simulation of Integral Joints

在钢桁梁整体节点板的传统分析方法中,杆件长度取为节点之间的理论距离,节点一般按刚接或铰接处理,不考虑节点刚域的影响,导致实测刚度大于理论计算值。针对这一不足,以榕江特大桥[(110+2×220+110)m连续钢桁梁柔性拱组合桥]为背景,选取2个完整节间,分别建立常规梁单元模型、多尺度模型和刚臂梁单元模型,对比3种模拟方法下各杆件的内力和组合应力,研究整体节点板刚度对结构力学效应的影响。结果表明:考虑节点刚域影响时可获得较为理想的计算结果;常规梁单元模型弱化了节点刚度,导致结构刚度偏低;多尺度模型能提高分析的精度,但处理过程过于复杂;刚臂梁单元模型计算结果偏于安全,可作为模拟节点刚度的一种简便方法。

In the traditional analysis methods for the integral joints of steel truss girder, the theoretical distances between the joints are taken as the length of the members, the joints are gen- erally treated as the rigid or hinged joints, not considering the influences of the rigid zones of the joints and the methods consequently cause the values of the measured rigidity to be greater than those of the theoretical calculation. In view of such deficiency of the methods, the Rong]iang River Bridge [-a hybrid bridge of continuous steel truss girder and flexible arches with span arrangement （110q-2X220-~l10） m-] was cited as an example, 2 complete panels of the steel truss girder of the bridge were selected and the common beam element model, multi-scale model and the rigid arm beam element model were respectively set up. The internal forces and combination stress of the different members of the models under the 3 kinds of the simulation methods were compared and the influences of the rigidity of the integral joints on the mechanical effect of the steel truss girder were studied. The results of the study show that when the influences of the rigid zones of the inte- gral joints are considered, the desired calculation results can be obtained. The common beam ele- ment model weakens the rigidity of the joints and results in the low rigidity of the structure. The multi-scale is too comp can be used model can improve the accuracy of the analysis, but the treatment process of the model licated. The calculation results of the rigid arm beam element model tend to be safe and as a simple and convenient method for simulation of the rigidity of the joints.