钢骨约束混凝土的约束机制及其应力-应变模型建立
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摘要
目前,钢骨混凝土(SRC)柱的试验结果与数值分析结果之间多无法良好吻合;究其原因,在于缺乏对钢骨约束混凝土的约束机制认识及与之相应的钢骨约束混凝土模型的建立。为此,该文在以往钢骨约束混凝土试验基础上,深入研究了带翼缘十字形钢骨对混凝土的约束机制,提出了钢骨对混凝土产生的实际侧向约束应力的简化分布形式,并以此将钢骨约束混凝土划分为钢骨强约束混凝土、钢骨弱约束混凝土和钢骨无约束混凝土。同时,通过计算有效侧向约束应力,确定了各钢骨约束区域可表征钢骨约束作用强弱的混凝土强度提高系数;借鉴经典的Mander模型,通过修正模型关键参数方法以建立各钢骨约束区域混凝土的应力-应变模型。引入该应力-应变模型的有限元分析和试验对比结果表明,该文所提出的钢骨约束混凝土的约束机制和所建立的钢骨约束混凝土应力-应变模型是合理且有效的。
Results from experimental and numerical analysis on SRC columns generally do not agree well at present. The main reason may be the lack of understanding on the confinement mechanism, as well as the application of corresponding stress-strain model for steel confined concrete. In this paper, the confinement mechanism of concrete by cross-shaped steel with flanges is studied in depth based on previous experimental results on steel confined concrete. Firstly, a simplified distribution of lateral stress imposed by steel confinement to concrete is proposed, based on which steel confined concrete was divided into three regions, including strong steel confined concrete, weak steel confined concrete and steel non-confined concrete. Confinement factors reflecting the confining level of steel to concrete for each region of the confined concrete were determined by calculating the effective lateral confining pressure. Based on Mander's model for stress-strain relationship of concrete considering the confining effect from spiral stirrup reinforcement, a unified stress-strain model for steel confined concrete is developed by modifying the key parameters of Mander's model. It is proved by comparing the results from experiment and numerical simulation utilizing the proposed stress-strain model that the confinement mechanism and the constitute model for steel confined concrete established in this paper are reasonable and effective.
Results from experimental and numerical analysis on SRC columns generally do not agree well at present. The main reason may be the lack of understanding on the confinement mechanism, as well as the application of corresponding stress-strain model for steel confined concrete. In this paper, the confinement mechanism of concrete by cross-shaped steel with flanges is studied in depth based on previous experimental results on steel confined concrete. Firstly, a simplified distribution of lateral stress imposed by steel confinement to concrete is proposed, based on which steel confined concrete was divided into three regions, including strong steel confined concrete, weak steel confined concrete and steel non-confined concrete. Confinement factors reflecting the confining level of steel to concrete for each region of the confined concrete were determined by calculating the effective lateral confining pressure. Based on Mander's model for stress-strain relationship of concrete considering the confining effect from spiral stirrup reinforcement, a unified stress-strain model for steel confined concrete is developed by modifying the key parameters of Mander's model. It is proved by comparing the results from experiment and numerical simulation utilizing the proposed stress-strain model that the confinement mechanism and the constitute model for steel confined concrete established in this paper are reasonable and effective.
引文
[1]赵鸿铁.钢与混凝土组合结构[M].北京:科学出版社,2001.Zhao Hongtie.Composite structures of steel and concrete[M].Beijing:Science Press,2001.(in Chinese)
[2]叶列平,方鄂华.钢骨混凝土柱的轴压力限值[J].建筑结构学报,1997,18(5):43―50.Ye Lieping,Fang Ehua.Axial load limit for steel reinforced concrete columns[J].Journal of Building Structures,1997,18(5):43―50.(in Chinese)
[3]叶列平,方鄂华.钢骨混凝土构件的受力性能研究综述[J].土木工程学报,2000,33(5):1―12.Ye Lieping,Fang Ehua.State of the art of study on the behaviors of steel reinforced concrete structure[J].China Civil Engineering Journal,2000,33(5):1―12.(in Chinese)
[4]胡敬礼,陈以一,赵宪忠,等.高含钢率SRC柱轴压承载性能研究[J].建筑结构学报,2008,29(3):24―30.Hu Jingli,Chen Yiyi,Zhao Xianzhong,et al.Ye Lieping,Fang Ehua.Study on loading capacity of high steel ratio SRC columns under axial compression[J].Journal of Building Structures,2008,29(3):24―30.(in Chinese)
[5]陈以一,王海生,赵宪忠,等.高含钢率SRC压弯柱滞回性能试验研究[J].建筑结构学报,2008,29(3):31―39.Chen Yiyi,Wang Haisheng,Zhao Xianzhong,et al.Experimental study on hysteretic behavior of SRC columns with high ratio of core steel[J].Journal of Building Structures,2008,29(3):31―39.(in Chinese)
[6]王海生.高含钢率钢骨混凝土柱滞回性能研究[D].上海:同济大学,2008.Wang Haisheng.Research on hysteretic behavior of steel reinforced concrete columns with high ratio of core steel[D].Shanghai:Tongji University,2008.(in Chinese)
[7]殷小溦,吕西林,卢文胜.配置十字型钢的型钢混凝土柱恢复力模型[J].工程力学,2014,31(1):97―103.Yin Xiaowei,Lu Xilin,Lu Wensheng.Resilience model of SRC columns with corss-shaped encase steel[J].Engineering Mechanics,2014,31(1):97―103.(in Chinese)
[8]秦浩,赵宪忠.高含钢率钢骨混凝土柱的滞回数值分析[J].结构工程师,2014,30(4):25―31.Qin Hao,Zhao Xianzhong.Numerical analysis of composite columns with high steel ratio under cyclic loading[J].Structural Engineers,2014,30(4):25―31.(in Chinese)
[9]赵宪忠,杨笑天,陈以一.钢骨截面延展性对高含钢率SRC柱静力性能的影响研究[J].土木工程学报,2016,49(1):31―41.Zhao Xianzhong,Yang Xiaotian,Chen Yiyi.Effect of shape distribution of encased steel section on static performance of steel reinforced concrete columns with high steel ratio[J].China Civil Engineering Journal,2016,49(1):31―41.(in Chinese)
[10]赵宪忠,杨笑天,陈以一.钢骨截面延展性对高含钢率SRC柱滞回性能的影响研究[J].土木工程学报,2016,49(3):80―90.Zhao Xianzhong,Yang Xiaotian,Chen Yiyi.Effect of shape distribution of encased steel section on hysteretic performance of steel reinforced concrete columns with high steel ratio[J].China Civil Engineering Journal,2016,49(3):80―90.(in Chinese)
[11]赵宪忠,秦浩,陈以一.十字形截面钢骨约束混凝土本构模型试验研究[J].建筑结构学报,2014,35(4):268―279.Zhao Xianzhong,Qin Hao,Chen Yiyi.Experimental and constitutive model study of steel confined concrete in SRC columns with cruciform steel section[J].China Civil Engineering Journal,2014,35(4):268―279.(in Chinese)
[12]Mander J B,Priestley M J N,Park R.Theoretical stress-strain model for confined concrete[J].Journal of Structural Engineering,1988,114(8):1804―1826.
[13]Schneider S P.Axially loaded concrete-filled steel tubes[J].Journal of Structural Engineering,1998,124(10):1125―1138.
[14]秦浩.高含钢率钢骨混凝土柱力学性能及恢复力模型研究[D].上海:同济大学,2013.Qin Hao.Performance and hysteretic model of SRC columns with high encased steel ratio[D].Shanghai:Tongji University,2013.(in Chinese)
[15]Park R,Priestley M J N,Gill W D.Ductility of square-confined concrete columns[J].Journal of the Structural Division,1982,108(4):929―950.
[16]Kent D C,Park R.Flexural members with confined concrete[J].Journal of the Structural Division,1971,97(7):1969―1990.
[17]Mirza S A,Skrabek B W.Statistical analysis of slender composite beam-column strength[J].Journal of Structural Engineering,1992,118(5):1312―1332.
[18]Chen S W,Wu P,Liu Q,et al.Studies on axially compressed SRC column using Q460 high-strength steel[C]//Proceedings of the 8th International Conference on Behavior of Steel Structures in Seismic Area.Shanghai:Science Press,2015:131―132.
[19]EI-Tawil S M,Deierlein G G.Fiber element analysis of composite beam-column cross-sections[G].New York:Cornell University,1996.
[20]Chen C C,Lin N J.Analytical model for predicting axial capacity and behavior of concrete encased steel composite stub columns[J].Journal of Constructional Steel Research,2006,62(5):424―433.
[21]蔡健,孙刚.方形钢管约束下核心混凝土的本构关系[J].华南理工大学学报:自然科学版,2008,36(1):105―109.Cai Jian,Sun Gang.Constitutive relationship of concrete core confined by square steel tube[J].Journal of South China University of Technology(Natural Science Edition),2008,36(1):105―109.(in Chinese)
[22]318 A C.Building code requirements for structural concrete(ACI 318M-11)and commentary[M].Farmington Hills,Mich:American Concrete Institute,2011.
[23]Ellobody E,Young B.Numerical simulation of concrete encased steel composite columns[J].Journal of Constructional Steel Research,2011,67(2):211―222.
[24]GB 50017—2003,钢结构设计规范[S].北京:中国计划出版社.2003.GB 50017—2003,Code for design of steel structures[S].Beijing:China Planning Press,2003.(in Chinese)
[2]叶列平,方鄂华.钢骨混凝土柱的轴压力限值[J].建筑结构学报,1997,18(5):43―50.Ye Lieping,Fang Ehua.Axial load limit for steel reinforced concrete columns[J].Journal of Building Structures,1997,18(5):43―50.(in Chinese)
[3]叶列平,方鄂华.钢骨混凝土构件的受力性能研究综述[J].土木工程学报,2000,33(5):1―12.Ye Lieping,Fang Ehua.State of the art of study on the behaviors of steel reinforced concrete structure[J].China Civil Engineering Journal,2000,33(5):1―12.(in Chinese)
[4]胡敬礼,陈以一,赵宪忠,等.高含钢率SRC柱轴压承载性能研究[J].建筑结构学报,2008,29(3):24―30.Hu Jingli,Chen Yiyi,Zhao Xianzhong,et al.Ye Lieping,Fang Ehua.Study on loading capacity of high steel ratio SRC columns under axial compression[J].Journal of Building Structures,2008,29(3):24―30.(in Chinese)
[5]陈以一,王海生,赵宪忠,等.高含钢率SRC压弯柱滞回性能试验研究[J].建筑结构学报,2008,29(3):31―39.Chen Yiyi,Wang Haisheng,Zhao Xianzhong,et al.Experimental study on hysteretic behavior of SRC columns with high ratio of core steel[J].Journal of Building Structures,2008,29(3):31―39.(in Chinese)
[6]王海生.高含钢率钢骨混凝土柱滞回性能研究[D].上海:同济大学,2008.Wang Haisheng.Research on hysteretic behavior of steel reinforced concrete columns with high ratio of core steel[D].Shanghai:Tongji University,2008.(in Chinese)
[7]殷小溦,吕西林,卢文胜.配置十字型钢的型钢混凝土柱恢复力模型[J].工程力学,2014,31(1):97―103.Yin Xiaowei,Lu Xilin,Lu Wensheng.Resilience model of SRC columns with corss-shaped encase steel[J].Engineering Mechanics,2014,31(1):97―103.(in Chinese)
[8]秦浩,赵宪忠.高含钢率钢骨混凝土柱的滞回数值分析[J].结构工程师,2014,30(4):25―31.Qin Hao,Zhao Xianzhong.Numerical analysis of composite columns with high steel ratio under cyclic loading[J].Structural Engineers,2014,30(4):25―31.(in Chinese)
[9]赵宪忠,杨笑天,陈以一.钢骨截面延展性对高含钢率SRC柱静力性能的影响研究[J].土木工程学报,2016,49(1):31―41.Zhao Xianzhong,Yang Xiaotian,Chen Yiyi.Effect of shape distribution of encased steel section on static performance of steel reinforced concrete columns with high steel ratio[J].China Civil Engineering Journal,2016,49(1):31―41.(in Chinese)
[10]赵宪忠,杨笑天,陈以一.钢骨截面延展性对高含钢率SRC柱滞回性能的影响研究[J].土木工程学报,2016,49(3):80―90.Zhao Xianzhong,Yang Xiaotian,Chen Yiyi.Effect of shape distribution of encased steel section on hysteretic performance of steel reinforced concrete columns with high steel ratio[J].China Civil Engineering Journal,2016,49(3):80―90.(in Chinese)
[11]赵宪忠,秦浩,陈以一.十字形截面钢骨约束混凝土本构模型试验研究[J].建筑结构学报,2014,35(4):268―279.Zhao Xianzhong,Qin Hao,Chen Yiyi.Experimental and constitutive model study of steel confined concrete in SRC columns with cruciform steel section[J].China Civil Engineering Journal,2014,35(4):268―279.(in Chinese)
[12]Mander J B,Priestley M J N,Park R.Theoretical stress-strain model for confined concrete[J].Journal of Structural Engineering,1988,114(8):1804―1826.
[13]Schneider S P.Axially loaded concrete-filled steel tubes[J].Journal of Structural Engineering,1998,124(10):1125―1138.
[14]秦浩.高含钢率钢骨混凝土柱力学性能及恢复力模型研究[D].上海:同济大学,2013.Qin Hao.Performance and hysteretic model of SRC columns with high encased steel ratio[D].Shanghai:Tongji University,2013.(in Chinese)
[15]Park R,Priestley M J N,Gill W D.Ductility of square-confined concrete columns[J].Journal of the Structural Division,1982,108(4):929―950.
[16]Kent D C,Park R.Flexural members with confined concrete[J].Journal of the Structural Division,1971,97(7):1969―1990.
[17]Mirza S A,Skrabek B W.Statistical analysis of slender composite beam-column strength[J].Journal of Structural Engineering,1992,118(5):1312―1332.
[18]Chen S W,Wu P,Liu Q,et al.Studies on axially compressed SRC column using Q460 high-strength steel[C]//Proceedings of the 8th International Conference on Behavior of Steel Structures in Seismic Area.Shanghai:Science Press,2015:131―132.
[19]EI-Tawil S M,Deierlein G G.Fiber element analysis of composite beam-column cross-sections[G].New York:Cornell University,1996.
[20]Chen C C,Lin N J.Analytical model for predicting axial capacity and behavior of concrete encased steel composite stub columns[J].Journal of Constructional Steel Research,2006,62(5):424―433.
[21]蔡健,孙刚.方形钢管约束下核心混凝土的本构关系[J].华南理工大学学报:自然科学版,2008,36(1):105―109.Cai Jian,Sun Gang.Constitutive relationship of concrete core confined by square steel tube[J].Journal of South China University of Technology(Natural Science Edition),2008,36(1):105―109.(in Chinese)
[22]318 A C.Building code requirements for structural concrete(ACI 318M-11)and commentary[M].Farmington Hills,Mich:American Concrete Institute,2011.
[23]Ellobody E,Young B.Numerical simulation of concrete encased steel composite columns[J].Journal of Constructional Steel Research,2011,67(2):211―222.
[24]GB 50017—2003,钢结构设计规范[S].北京:中国计划出版社.2003.GB 50017—2003,Code for design of steel structures[S].Beijing:China Planning Press,2003.(in Chinese)