脱空缺陷对钢管混凝土拉弯构件性能的影响分析
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摘要
在合理选用材料本构、单元类型、网格划分和边界条件的基础上,采用有限元分析软件建立了考虑脱空缺陷的钢管混凝土拉弯构件有限元分析模型。在验证模型可靠性的基础上,通过对比分析有无脱空缺陷的钢管混凝土拉弯构件的荷载-变形关系曲线、钢管与混凝土拉力分配、界面接触应力等力学性能指标,明晰了脱空缺陷对钢管混凝土拉弯构件受力性能的影响机理。研究结果表明:球冠形脱空缺陷削弱了钢管对混凝土的约束作用,在构件受拉弯荷载时,混凝土受压区开裂严重因而对构件的抗拉承载力贡献较无脱空构件低;外钢管拉力分配比重较高,所受应力较大,且钢管脱空侧由于缺少混凝土支撑作用从而出现局部屈曲,降低了构件抗拉承载力;构件的抗拉承载力系数随脱空率的增大而减小,但减小幅度趋于平缓;相同脱空率下承载力系数随偏心率增大而降低。
Based on the rational constitutive relation of materials,element type,meshing and boundary conditions,a finite element model( FEM) was established for the concrete-filled steel tubular( CFST) with spherical cap gap subjected to bending and tension. A close agreement was achieved by comparing the load-deformation responses and ultimate strength of FEM and test results. In order to clarify the influence of gap on the mechanical properties of CFST members under bending and tension,a comparative analysis was conducted on the CFST members with or without gap in terms of the load-deformation relationship,tension distribution of tubes and concrete,interface contact stress and so on. The results showed that the spherical cap gap would weaken the confinement effect of steel tube to concrete.When the member were subjected to tension and bending,it would result in more serious cracking at the compression zone of the concrete,and contributed less to the tensile bearing capacity of the member with spherical cap gap than that of the member without gap. The proportion of tensile force of the outer steel pipe was higher and the stress was greater. Meanwhile,local buckling was more likely to occur in the steel tube because of lacking the support of concrete at the location of gap. From the parametric analysis results,it was found that the tensile bearing capacity of the CFST members decreased with the increase of gap ratio. With the same gap ratio,the reduction of ultimate strength caused by gap tended to be more significant when the eccentric ratio increased.
Based on the rational constitutive relation of materials,element type,meshing and boundary conditions,a finite element model( FEM) was established for the concrete-filled steel tubular( CFST) with spherical cap gap subjected to bending and tension. A close agreement was achieved by comparing the load-deformation responses and ultimate strength of FEM and test results. In order to clarify the influence of gap on the mechanical properties of CFST members under bending and tension,a comparative analysis was conducted on the CFST members with or without gap in terms of the load-deformation relationship,tension distribution of tubes and concrete,interface contact stress and so on. The results showed that the spherical cap gap would weaken the confinement effect of steel tube to concrete.When the member were subjected to tension and bending,it would result in more serious cracking at the compression zone of the concrete,and contributed less to the tensile bearing capacity of the member with spherical cap gap than that of the member without gap. The proportion of tensile force of the outer steel pipe was higher and the stress was greater. Meanwhile,local buckling was more likely to occur in the steel tube because of lacking the support of concrete at the location of gap. From the parametric analysis results,it was found that the tensile bearing capacity of the CFST members decreased with the increase of gap ratio. With the same gap ratio,the reduction of ultimate strength caused by gap tended to be more significant when the eccentric ratio increased.
引文
[1]韩林海.钢管混凝土结构:理论与实践[M].3版.北京:科学出版社,2016.
[2]LIAO F Y,HAN L H,HE S H.Behavior of CFST Short Column and Beam with Initial Concrete Imperfection:Experiments[J].Journal of Constructional Steel Research,2011,67(12):1922-1935.
[3]LIAO F Y,HAN L H,TAO Z.Behaviour of CFST Stub Columns with Initial Concrete Imperfection:Analysis and Calculations[J].Thin-Walled Structures,2013,70(13):57-69.
[4]叶勇,韩林海,陶忠.脱空对圆钢管混凝土受剪性能的影响分析[J].工程力学,2016,6(增刊):62-67.
[5]HAN L H,YE Y,LIAO F Y.Effects of Core Concrete Initial Imperfection on Performance of Eccentrically Loaded CFST Columns[J].Journal of Structural Engineering,ASCE,2016.DOI:10.1061/(ASCE)ST.1943-541X.0001604.
[6]叶勇,李威,陈锦阳.考虑脱空的方钢管混凝土短柱轴压性能有限元分析[J].建筑结构学报,2015,39(增刊1):324-329.
[7]韩浩,廖飞宇,李永进.反复荷载下带脱空缺陷的钢管混凝土压弯构件的有限元模拟[C]∥第25届全国结构工程会议论文集.包头:2016:184-188.
[8]沈聚敏,王传志,江见鲸.钢筋混凝土有限元与板壳极限分析[M].北京:清华大学出版社,1993.
[9]刘威.钢管混凝土局部受压时的工作机理研究[D].福州:福州大学,2005.
[10]LI W,HAN L H,CHAN T M.Performance of Concrete-Filled Steel Tubes Subjected to Eccentric Tension[J].Journal of Structural Engineering,ASCE,2015,141(12).
[11]彭志强.带脱空缺陷的不锈钢管混凝土构件在偏拉作用下的力学性能研究[D].福州:福建农林大学,2017.
[2]LIAO F Y,HAN L H,HE S H.Behavior of CFST Short Column and Beam with Initial Concrete Imperfection:Experiments[J].Journal of Constructional Steel Research,2011,67(12):1922-1935.
[3]LIAO F Y,HAN L H,TAO Z.Behaviour of CFST Stub Columns with Initial Concrete Imperfection:Analysis and Calculations[J].Thin-Walled Structures,2013,70(13):57-69.
[4]叶勇,韩林海,陶忠.脱空对圆钢管混凝土受剪性能的影响分析[J].工程力学,2016,6(增刊):62-67.
[5]HAN L H,YE Y,LIAO F Y.Effects of Core Concrete Initial Imperfection on Performance of Eccentrically Loaded CFST Columns[J].Journal of Structural Engineering,ASCE,2016.DOI:10.1061/(ASCE)ST.1943-541X.0001604.
[6]叶勇,李威,陈锦阳.考虑脱空的方钢管混凝土短柱轴压性能有限元分析[J].建筑结构学报,2015,39(增刊1):324-329.
[7]韩浩,廖飞宇,李永进.反复荷载下带脱空缺陷的钢管混凝土压弯构件的有限元模拟[C]∥第25届全国结构工程会议论文集.包头:2016:184-188.
[8]沈聚敏,王传志,江见鲸.钢筋混凝土有限元与板壳极限分析[M].北京:清华大学出版社,1993.
[9]刘威.钢管混凝土局部受压时的工作机理研究[D].福州:福州大学,2005.
[10]LI W,HAN L H,CHAN T M.Performance of Concrete-Filled Steel Tubes Subjected to Eccentric Tension[J].Journal of Structural Engineering,ASCE,2015,141(12).
[11]彭志强.带脱空缺陷的不锈钢管混凝土构件在偏拉作用下的力学性能研究[D].福州:福建农林大学,2017.