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使用有限元法研究受约束蜂窝钢梁(CSB)在火灾中的大挠度变形。对一种新型的多边形开孔形状的蜂窝钢梁进行研究。有限元模型所给出的承载力通过了实心腹板约束钢梁在火灾高温下的数值结果的验证。蜂窝钢梁的研究参数包括扩张比、腹板开孔大小、腹板开孔形状、腹板开孔位置以及对钢梁的弹性轴向约束。介绍端部反应力的发展、跨中挠度以及高温下受约束蜂窝钢梁临界区域的弯矩。为了让受约束蜂窝钢梁的轴向刚度小于实心腹板钢梁的轴向刚度,火灾中受约束蜂窝钢梁的热伸长所造成的压力要小于实心腹板钢梁的压力。且将较低温度下进入悬链作用阶段的受约束蜂窝钢梁与实心腹板钢梁相比较。结果表明:腹板开孔的大小、形状和位置对火灾中受约束蜂窝钢梁的悬链作用的影响很小。
Finite Element Method (FEM) is used to study the large deflection deformation of a confined honeycomb girder (CSB) during a fire. A new type of honeycomb steel beam with polygonal open cell shape was studied. The bearing capacity given by the finite element model has been verified by the numerical results of solid web-confined steel beams under high fire temperatures. Research parameters of honeycomb steel beams include expansion ratio, web hole size, web hole shape, web hole location, and elastic axial restraint on the steel beam. The development of end reaction force, midspan deflection and bending moment of the confined honeycomb beam in critical region are introduced. In order to make the axial stiffness of the constrained honeycomb girder smaller than the axial rigidity of the solid web steel girder, the pressure caused by the thermal elongation of the confined honeycomb girder in the fire is smaller than that of the solid web steel girder. And the confined honeycomb girder entering the catenary stage at lower temperature is compared with the solid web steel girder. The results show that the size, shape and location of web openings have little effect on the catenary effect of confined honeycomb girders in fire.