(1 东北石油大学黑龙江省高校防灾减灾工程与防护工程重点实验室， 大庆 163318；2 香港理工大学土木与环境工程系， 香港 999077)

［摘要］为研究实腹式双钢管异强混凝土(CFDST)组合短柱的轴压性能，以长细比（λ）、核心混凝土和夹层混凝土抗压强度 (fcki，fcko)、内外钢管厚度(ti，to)、直径(Di，Do)及抗拉强度(fyki，fyko)为主要参数，共设计21根CFDST组合短柱。基于钢材简化的双线性本构模型和考虑约束效应的核心、夹层混凝土非线性本构模型，采用ABAQUS软件对18根双钢管混凝土组合短柱试件进行了数值仿真，获得短柱竖向荷载-位移关系曲线。通过与已有的试验数据对比，验证了材料本构模型和有限元建模的合理性。基于此对CFDST组合短柱进行扩展参数分析，考察了不同参数对该类短柱轴压承载力的影响规律，获得此类构件的受力机理、应力分布规律及破坏形态。结果表明，随fcki，to，Do和fcko的增大，CFDST组合短柱的轴压承载力均会显著提高。而随λ的增加，CFDST组合短柱的轴压承载力却逐渐减小。所有试件均表现出较优越的持荷能力和中部外凸膨胀的破坏形态。由圆心向外CFDST组合短柱的约束效应逐渐递减。最后，引入内外管的约束效应系数（ξi，ξo），采用1stOpt软件统计回归出CFDST组合短柱轴压承载力计算表达式, 并给出该类短柱的相应设计建议，为该类新型组合柱在实际工程中推广应用奠定基础。

［关键词］约束效应； 轴压承载力； 受力机理； 长细比； 本构模型

中图分类号：TU398-7文献标识码：A文章编号：1002-848X(2020)05-0120-10

Research on axial compression bearing capacity of different-strength concrete filled double steel tube short columns

Ji Jing1,2, Yu Dianyou1, Jiang Liangqin1, Liu Yingchun1, Yang Maomao1, Song Huayu1, Jiang Li1

(1 Heilongjiang Key Laboratory of Disaster Prevention, Mitigation and Protection Engineering, Northeast Petroleum University, Daqing 163318, China; 2 Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hongkong 999077, China)

Abstract:To investigate axial compression performance of different-strength concrete filled double steel tube (CFDST) short columns, 21 CFDST short columns were designed considering main parameters of slenderness ratio (λ), compression strength of core and sandwich concrete (fcki, fcko), thickness of inner and outer steel tubes (ti, to) and diameter of inner and outer steel tubes (Di, Do), and tensile strength of inner and outer steel tubes (fyki, fyko). Based on the simplified bilinear constitutive model for steel tubes and nonlinear constitutive models for core and sandwich concrete considering the constraint effect, numerical simulation analysis of 18 CFDST short columns was carried out by using software ABAQUS, and vertical load-displacement curves were obtained. The rationality of the material constitutive models and finite element (FE) model was verified by comparing with existing experimental results. The parameter analysis for  CFDST short columns were conducted and the influence of different parameters on axial compression bearing capacity was investigated. Then the force mechanism, stress distribution and failure mode of short columns were obtained. The results show that axial compression bearing capacity of CFDST short columns increases significantly by increasing of fcki, to, Do, and fcko. However, with the increasing of λ, axial compression bearing capacity of CFDST short columns decreases gradually. All specimens show superior load-holding capacity and convex expansion failure modes in the middle of specimens. Constraint effect of CFDST short columns decreases gradually from the center to the outside. Finally, by introducing constraint effect coefficient (ξi, ξo) of inner and outer steel tubes, the expression of axial compression bearing capacity of CFDST short columns was established by  1stOpt software, and the design suggestions of this kind short column were also given, providing basis for popularization and application of this kind of new composite columns in practical engineering projects.

Keywords:constraint effect; axial compression bearing capacity; stress mechanism; slenderness ratio; constitutive model

*国家自然科学基金面上项目(51178087)，黑龙江省级领军人才梯队后备带头人资助项目(RCHB-2015-1)，哈尔滨工业大学结构灾变与控制教育部重点实验室开放基金项目（HITCE201908），黑龙江省教育厅科研专项 (2016YSFX-02)，东北石油大学研究生创新科研项目(JYCX_CX05_2018)。

通讯作者:姜良芹，硕士，副教授，Email:  jiangliangqin 1978@163.com。