考虑初应力的方钢管混凝土柱轴压极限承载力统一解*
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(1 长安大学建筑工程学院， 西安 710061； 2 世茂房地产有限公司， 西安 710021； 3 长安大学地质工程与测绘学院， 西安 710054)
［摘要］采用双剪统一强度理论，考虑钢管初应力、中间主应力及材料拉压比的影响，对方钢管混凝土短柱的受力机理进行分析。将核心混凝土划分为有效约束区和非有效约束区，引入长细比折减系数，建立考虑初应力的方钢管混凝土柱轴压极限承载力的统一解。通过与试验结果和数值模拟结果的比对，验证了公式的正确性，并针对各参数的影响特性进行讨论。研究结果表明：考虑初应力的方钢管混凝土柱的轴压极限承载力随侧压系数、统一强度理论参数、考虑长细比影响的稳定系数等的增大而增大，随初应力、广义宽厚比等的增大而减小。对考虑初应力的方钢管混凝土柱的研究有一定的参考意义。［关键词］双剪统一强度理论; 方钢管混凝土; 初应力; 轴压极限承载力中图分类号：TU398 文献标识码：A 文章编号：1002-848X(2016)04-0056-06
Unified solution of axial compression ultimate bearing capacity for concrete-filled square steel tubular column with initial stressZhao Junhai1, Feng Wenyu1, Ling Yun2, Li Yan3(1 School of Civil Engineering, Chang'an University, Xi'an 710061, China; 2 Shimao Property Holdings Limited, Xi'an 710021, China; 3 School of Geology Engineering and Geomatics, Chang'an University, Xi'an 710054, China)Abstract:Based on the twin shear unified strength theory, the mechanical behavior of concrete-filled square steel tubular (CFSST) short column was analyzed by considering influences of initial stress of steel tube, intermediate principal stress and tension-compression ratio of materials. The core concrete was divided into effective constraint region and invalid constraint region, and the unified solution of axial compression ultimate compression bearing capacity of CFSST column was established by introducing the reduction factor of slenderness ratio. Compared with the results of experiments and numerical simulations, the correctness of the proposed formula was verified. Furthermore, the effects of some parameters on the ultimate compression bearing capacity were discussed. The research results indicate that the axial compression ultimate bearing capacity of CFSST column increases with the increase of side pressure coefficient, parameter of unified strength theory and stability factor considering slenderness ratio, while it decreases with the increase of initial stress and broad width-to-thickness ratio. The results may provide reference for research of CFSST column with initial stress.Keywords:twin shear unified strength theory; concrete-filled square steel tube; initial stress; axial compression ultimate bearing capacity
*国家自然科学基金项目(41202191)，陕西省社会发展科技攻关项目（2015SF272），陕西省自然科学基础研究计划项目（2014JQ7290，2015JM4146）。作者简介：赵均海，教授，博士生导师，Email: zhaojh@chd.edu.cn。
