矩形钢管高强混凝土双向压弯构件截面强度

Cross-sectional strength of high-strength concrete-filled RHS steel tubes subjected to axial compression and bi-axial bending moment

针对实际工程中方形和矩形钢管高强混凝土双向压弯构件受力时的两种典型加载路径,编制了非线性数值计算程序,对双向压弯构件截面进行了分析,材料本构关系以方形、矩形钢管高强混凝土轴压短柱试验为基础,并考虑了材料加卸载作用的影响.利用所编制的程序,分析了两种典型加载路径下双向压弯构件截面的荷载-变形关系全过程曲线,同时分析了残余应力对截面的荷载-变形关系全过程曲线的影响,讨论了截面长宽比、钢材屈服强度、混凝土强度、含钢率、加载路径及加载角度等参数对截面强度承载力的影响.最后给出了方形和矩形钢管高强混凝土双向压弯构件截面的三维强度承载力相关关系及其简化计算公式,并将简化计算公式计算结果与程序计算结果行了比较,两者吻合较好.

This paper presented a detailed study on the cross-sectional strength of high -strength concrete - filled square hollow section （SHS） and rectangular hollow section （RHS） steel tubes subjected to axial compression and bi - axial bending moment. The two most possible loading - paths in engineering practice were selected in the investigation of behavior of rectangular composite columns. Based on the axial compressive experiments of stocky columns, a nonlinear numerical program was developed to carry out calculation and analysis on the cross - sectional strength with special consideration for loading and unloading effects. Then, the influence of height - to - breadth ratio, steel yield strength, concrete strength, steel ratio, loading - paths and loading - angles on compression and moment strength inter - relation curves was analyzed. The effects of residual stress on the load-deformation curves were also investigated. Finally, the simplified formula on cross - sectional strength My/M0y - M/M0z - Nu/N0 surface was given. The results based on the simplified formula are compared with those of experiment, and they agreed well with each other.