同含钢率钢管与配筋钢管混凝土柱的受力性能分析

Mechanical Properties of Same-steel-ratio Concrete-filled and Reinforced Concrete-filled Steel Tube Columns

为阐明含钢率对构件的力学特性的影响规律,基于有限元分析方法研究了配筋钢管混凝土(reinforced concrete-filled steel tube,R-CFST)和钢管混凝土(concrete filled-steel tube,CFST)短柱的轴压性能。首先建立了适合R-CFST的材料本构模型和分析方法并用既有的实验数据验证模型的可靠性,之后进行了36根6种不同含钢率的R-CFST和对应的CFST有限元分析,通过分析荷载-位移响应、承载力、单位面积钢材对构件承载力提高量和延性等指标,最终发现:当混凝土强度较低时,含钢率越低CFST的承载力和延性比同含钢率R-CFST高,但随着混凝土强度的提高,含钢率越大反而使得R-CFST的性能得以显著提高;单位面积R-CFST纵筋对承载力的贡献率都大于单位面积的CFST钢管的贡献率,而且随着混凝土强度的提高R-CFST的这种贡献更为明显;填充高强度混凝土时,R-CFST比CFST更有效。由此得出结论:CFST内配筋比增加钢管壁厚更有效,尤其是填充高强度混凝土时配筋的效果更为明显。

To evaluate the effect of steel ratio on overall performance of concrete-filled steel tube(CFST)and reinforced concrete-filled steel tube(R-CFST)columns,the axial compression behavior of R-CFST and concrete CFST short columns were studied based on the finite element analysis method.Material models and analyses method applicable for R-CFST were proposed and the model was validated using known experimental results,in which 36 models of R-CFST and respective CFST at 6 different steel ratios were tested.The load-displacement response,load bearing capacity,contribution of steel to the strength on per unit area and ductility were scrutinized.Results show that the bearing capacity and ductility of CFST were higher than that of R-CFST of the same steel ratio when the concrete strength and steel ratio were smaller,the bearing capacity and ductility of R-CFST tended to increase with the increase of concrete strength and steel ratio.The strength contribution of longitudinal reinforcement of R-CFST on per unit area was higher than that of CFST steel tube on per unit area,and that of R-CFST was more significant as concrete strength increased.When filled with high-strength concrete,the R-CFST columns were more effective than those of the CFST.Therefore,configuring the reinforcement of CFST is more effective than just increasing the wall-thickness of steel tube,especially when filled with high-strength concrete.