考虑楼板组合作用的方钢管混凝土组合框架受力性能有限元分析

Finite element analysis on behavior of rectangular CFST frame considering composite action of floor slab

为了对组合框架结构的抗震性能进行深入的研究,基于方钢管混凝土组合框架低周往复荷载试验的足尺试件,采用通用有限元软件Msc.Marc建立了壳-实体精细非线性有限元分析模型,考虑了钢材及混凝土的弹塑性性能,混凝土的开裂及受拉软化,钢梁与混凝土楼板交界面的滑移以及钢梁下翼缘断裂等非线性因素,对4榀组合框架及2榀组合节点进行了非线性有限元分析。有限元分析结果与试验结果吻合良好,说明提出的壳-实体精细线性有限元分析模型能够较好地模拟组合框架受力性能的影响。研究表明,考虑楼板组合作用后,组合梁框架的变形及内力将不同于传统的钢框架结构,并且梁柱节点的受力性能也将发生改变,若要实现基于性能的结构抗震设计概念,应采用组合梁的刚度及强度进行结构弹性及弹塑性阶段的抗震设计。

Based on the full-scale cyclic test results of rectangular CFST composite frames,refined nonlinear shell-entities finite element（FE） analysis model were established using Msc.Marc to further study the composite frame.A number of nonlinearities such as the elasto-plastic properties of steel and concrete,concrete cracking,tension softening,interface slip between concrete slabs and steel beams and fracture of beam bottom flange were considered in the analysis.The test specimens,including 4 full-scale composite frames and 2 composite joints,have been analyzed.The analysis results agree well with the test results,indicating that the shell-entities FE models were a good simulation of composite frames.Studies show that after considering the composite action of the floor slab and steel beam,the deformation and internal forces of the composite frame will be different from those of the traditional steel frame,and the mechanical properties of beam-column joint will also change.In order to achieve the seismic design concepts of ＇strong column-weak beam＇ and ＇strong joint-weak component＇,the real rigidity and strength of composite beams should be used for the elastic and elasto-plastic seismic design of composite frames.