矩形高强钢管混凝土壁板弹塑性屈曲及宽厚比限值解析解

Analytical solution of elastic-plastic buckling and width-to-thickness ratio limits of rectangular CFST with high-strength steel panels

钢管混凝土壁板的局部屈曲可通过限制其宽厚比来避免。为了得到矩形高强钢管混凝土柱壁板的宽厚比限值,将其简化为受混凝土单侧约束板,以薄板的弹塑性局部屈曲理论为基础,采用Bleich近似计算方法和Ramberg-Osgood高强钢材本构模型,推导出了受单侧约束板在均布压应力作用下的弹塑性屈曲应力,得到了矩形高强钢管混凝土柱壁板宽厚比限值的解析解。进而采用有限元模型进行了屈服强度为460~960 MPa、宽厚比为20~60共计168组矩形高强钢管混凝土轴压构件的有限元模拟,模拟结果与已有的试验结果验证了所提出的宽厚比限值解析解的可靠性。与现行各国相关规范的对比分析表明,所提出的宽厚比限值解析解与欧洲BS EN 1994-1-1的计算结果仅相差3%。建议在设计矩形高强钢管混凝土柱时,壁板的宽厚比限值可偏保守地取本文解析解和BS EN 1994-1-1计算结果的较小值。

The local buckling of concrete-filled steel tube panels can be avoided by limiting their width-to-thickness ratio.To obtain the width-to-thickness ratio limits of rectangular concrete-filled high-strength steel tube panels,this paper simplified the panel to a rectangular thin plate with unilateral constraints of concrete.Based on the elastic-plastic local buckling theory,using the Bleich approximate calculation method and the Ramberg-Osgood constitutive model for high-strength steel,the elastic-plastic buckling stress of plate with unilateral constraints under uniform axial pressure was derived,and the analytical solution of width-to-thickness ratio limits was obtained.Furthermore,the finite element models were used to simulate the axial compressive behavior of 168 rectangular concrete-filled high-strength steel tubes with a yield strength of 460 MPa to 960 MPa and a width-to-thickness ratio of 20 to 60.The reliability of the analytical solution of the width-to-thickness ratio limits proposed in this paper was verified by the simulated results and the existing test results.Compared with the current codes,the analytical solution of the width-to-thickness ratio limits proposed in this paper is only 3%different from that of BS EN 1994-1-1.It is suggested that when designing rectangular concrete-filled high-strength steel tubular columns,the width-to-thickness ratio limits of the panels can be conservatively taken as the smaller value between the analytical solution of this paper and the result of BS EN 1994-1-1 calculation.