考虑蠕变效应的钢柱高温承载力计算方法
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摘要
高温蠕变对火灾下钢构件的内力和变形影响较大,现行《建筑钢结构防火技术规范》(GB51249—2017)中未考虑蠕变对钢柱高温承载力的影响。采用ANSYS软件分析考虑蠕变后钢柱在高温下的受力性能,并与钢柱的抗火试验进行对比,发现考虑蠕变的钢柱有限元模拟结果与试验数据吻合更好。利用验证的有限元模型进行参数分析,结果表明:考虑蠕变效应后,钢柱的高温承载力受初始缺陷(残余应力、初弯曲、初偏心)、弯曲方向、荷载比、长细比、升温速率的影响较大,受截面形式和钢材屈服强度的影响较小。给出了考虑蠕变效应后计算钢柱高温承载力的简化方法。
The creep deformations developed in steel significantly affect the deformation and bearing capacity of steel structures in fire.However,such creep effect was not considered in fire-resistance calculation method of steel columns in current specification of Code for Fire Safety of Steel Structures in Buildings(GB 51249-2017).Load bearing capacity of steel columns at elevated temperature after considering creep effect was analyzed by ANSYS soft package.A comparative study is performed in this paper to compare the finite element results with measured data obtained from fire test,and it is found that the numerical results and measurements show good agreement when considering the creep effect.Subsequently,the validated model was used for parametric studies.It is shown that the initial imperfection(i.e.,residual stress,geometric imperfection,and load eccentricity),bend direction,load ratio,slenderness ratio and heating rate have a significant influence on the load bearing capacity of steel columns when considering high temperature creep.In contrast,the load bearing capacity of steel columns is less sensitive to the section shape and yield strength of steel.A simple design method is proposed to calculate the load bearing capacity of steel columns at elevated temperature.
The creep deformations developed in steel significantly affect the deformation and bearing capacity of steel structures in fire.However,such creep effect was not considered in fire-resistance calculation method of steel columns in current specification of Code for Fire Safety of Steel Structures in Buildings(GB 51249-2017).Load bearing capacity of steel columns at elevated temperature after considering creep effect was analyzed by ANSYS soft package.A comparative study is performed in this paper to compare the finite element results with measured data obtained from fire test,and it is found that the numerical results and measurements show good agreement when considering the creep effect.Subsequently,the validated model was used for parametric studies.It is shown that the initial imperfection(i.e.,residual stress,geometric imperfection,and load eccentricity),bend direction,load ratio,slenderness ratio and heating rate have a significant influence on the load bearing capacity of steel columns when considering high temperature creep.In contrast,the load bearing capacity of steel columns is less sensitive to the section shape and yield strength of steel.A simple design method is proposed to calculate the load bearing capacity of steel columns at elevated temperature.
引文
[1]李国强,王培军,王永昌,等.约束钢柱抗火性能试验研究[J].建筑结构学报,2009,30(5):184-190.LI G Q,WANG P J,WANG Y C.Experimental study on restrained steel column subjected to fire[J].Journal of Building Structures,2009,30(5):184-190.(in Chinese)
[2]何平召,王卫永.约束高强度Q460钢梁抗火性能研究[J].土木建筑与环境工程,2015,37(2):52-59.HE P Z,WANG W Y.Fire resistance performance on restrained high strength Q460steel beams[J].Journal of Civil,Architectural and Environmental Engineering,2015,37(2):52-59.(in Chinese)
[3]王卫永,李国强.高强度钢柱高温下承载力数值计算方法[J].土木建筑与环境工程,2011,33(6):13-18.WANG W Y,LI G Q.Numerical method for load bearing capacity of high strength steel columns at elevated temperature[J].Journal of Civil,Architectural and Environmental Engineering,2011,2011,33(6):13-18.(in Chinese)
[4]YANG K C,YANG F C.Fire performance of restrained welded steel box columns[J].Journal of Constructional Steel Research,2015,107:173-181.
[5]KERVALISHVILI A,TAKVIK I.Modified procedure for buckling of steel columns at elevated temperatures[J].Journal of Constructional Steel Research,2016,127:108-119.
[6]KODUR V K R,DWAIKAT M.Effect of high temperature creep on the fire response of restrained steel beams[J].Materials&Structures,2010,43(10):1327-1341.
[7]建筑钢结构防火技术规范:GB 51249-2017[S].北京:中国计划出版社,2017.Code for fire safety of steel structures in buildings:GB51249-2017[S].Beijing:China Planning Press,2017.(in Chinese)
[8]MOROVAT M A,ENGELHARDT M D,HELWIG TA,et al.High-temperature creep buckling phenomenon of steel columns subjected to fire[J].Journal of Structural Fire Engineering,2014,5(3):189-202.
[9]European Committee for Standardization EN 1993-1-2,Eurocode 3.Design of steel structures,Part 1.2:General rules-structural fire design[S].Brussels,2005.
[10]李国强,吴波,韩林海.结构抗火研究进展与趋势[J].建筑钢结构进展,2006,8(1):1-13.LI G Q,WU B,HAN L H.Development of the research on fire-resistance of structures[J].Progress in Steel Building Structure,2006,8(1):1-13.(in Chinese)
[11]WANG W Y,YAN S H,KODUR V.Temperature induced creep in low-alloy structural Q345steel[J].Journal of Materials in Civil Engineering,2016,28(6):06016003
[12]WANG W Y,YAN S H,LIU J P.Test on temperature induced creep in high strength Q460steel[J].Materials&Structures,2017,50:68.
[13]王卫永,何平召.考虑高温蠕变影响的钢梁抗火性能[J].防灾减灾工程学报,2016,36(3):486-492.WANG W Y,HE P Z.Fire resistance of steel beams considering creep at elevated temperatures[J].Journal of Disaster Prevention and Mitigation Engineering,2016,36(3):486-492.(in Chinese)
[14]王卫永,何平召.蠕变模型对约束钢梁抗火性能分析的影响[J].土木建筑与环境工程,2015,37(5):41-47.WANG W Y,HE P Z.Effect of creep models on the fire resistance analysis of restrained steel beams[J].Journal of Civil,Architectural and Environmental Engineering,2015,37(5):41-47.(in Chinese)
[15]王芳,王卫永.高温蠕变对高强度Q460钢柱抗火性能的影响[J].工业建筑,2016,46(7):74-80.WANG F,WANG W Y.Effect of high temperature creep on the fire resistance of high strengthQ460steel columns[J].Industrial Constructions,2016,46(7):74-80.(in Chinese)
[16]王卫永,何平召.考虑蠕变的约束钢梁抗火性能分析方法[J].重庆大学学报,2017,40(11):65-72.WANG W Y,HE P Z.Approach to analysis fire resistance of restrained steel beams after considering creep effect[J].Journal of Chongqing University,2017,40(11):65-72.(in Chinese)
[17]KODUR V K R,DWAIKAT M M S.Effect of high temperature creep on fire response of restrained steel beams[J].Materials&Structures,2010,43(10):1327-1341.
[18]LUECKE W E,MCCOLSKEY J D,MCCOWAN CN,et al.Federal building and fire safety investigation of the World Trade Center disater:mechanical properties of structural steels[R].Gaithersburg:National Institute of Standards and Technology,2015.
[19]AZPIAZU W,UNANUE J A.Buckling curves for hot rolled H profiles submitted to fire[R].Bilbao:LABEIN,1993.
[20]钢结构设计规范:GB 50017-2017[S].北京:中国计划出版社,2017.Code for design of steel structures:GB 50017-2017[S].Beijing:China Planning Press,2017.(in Chinese)
[2]何平召,王卫永.约束高强度Q460钢梁抗火性能研究[J].土木建筑与环境工程,2015,37(2):52-59.HE P Z,WANG W Y.Fire resistance performance on restrained high strength Q460steel beams[J].Journal of Civil,Architectural and Environmental Engineering,2015,37(2):52-59.(in Chinese)
[3]王卫永,李国强.高强度钢柱高温下承载力数值计算方法[J].土木建筑与环境工程,2011,33(6):13-18.WANG W Y,LI G Q.Numerical method for load bearing capacity of high strength steel columns at elevated temperature[J].Journal of Civil,Architectural and Environmental Engineering,2011,2011,33(6):13-18.(in Chinese)
[4]YANG K C,YANG F C.Fire performance of restrained welded steel box columns[J].Journal of Constructional Steel Research,2015,107:173-181.
[5]KERVALISHVILI A,TAKVIK I.Modified procedure for buckling of steel columns at elevated temperatures[J].Journal of Constructional Steel Research,2016,127:108-119.
[6]KODUR V K R,DWAIKAT M.Effect of high temperature creep on the fire response of restrained steel beams[J].Materials&Structures,2010,43(10):1327-1341.
[7]建筑钢结构防火技术规范:GB 51249-2017[S].北京:中国计划出版社,2017.Code for fire safety of steel structures in buildings:GB51249-2017[S].Beijing:China Planning Press,2017.(in Chinese)
[8]MOROVAT M A,ENGELHARDT M D,HELWIG TA,et al.High-temperature creep buckling phenomenon of steel columns subjected to fire[J].Journal of Structural Fire Engineering,2014,5(3):189-202.
[9]European Committee for Standardization EN 1993-1-2,Eurocode 3.Design of steel structures,Part 1.2:General rules-structural fire design[S].Brussels,2005.
[10]李国强,吴波,韩林海.结构抗火研究进展与趋势[J].建筑钢结构进展,2006,8(1):1-13.LI G Q,WU B,HAN L H.Development of the research on fire-resistance of structures[J].Progress in Steel Building Structure,2006,8(1):1-13.(in Chinese)
[11]WANG W Y,YAN S H,KODUR V.Temperature induced creep in low-alloy structural Q345steel[J].Journal of Materials in Civil Engineering,2016,28(6):06016003
[12]WANG W Y,YAN S H,LIU J P.Test on temperature induced creep in high strength Q460steel[J].Materials&Structures,2017,50:68.
[13]王卫永,何平召.考虑高温蠕变影响的钢梁抗火性能[J].防灾减灾工程学报,2016,36(3):486-492.WANG W Y,HE P Z.Fire resistance of steel beams considering creep at elevated temperatures[J].Journal of Disaster Prevention and Mitigation Engineering,2016,36(3):486-492.(in Chinese)
[14]王卫永,何平召.蠕变模型对约束钢梁抗火性能分析的影响[J].土木建筑与环境工程,2015,37(5):41-47.WANG W Y,HE P Z.Effect of creep models on the fire resistance analysis of restrained steel beams[J].Journal of Civil,Architectural and Environmental Engineering,2015,37(5):41-47.(in Chinese)
[15]王芳,王卫永.高温蠕变对高强度Q460钢柱抗火性能的影响[J].工业建筑,2016,46(7):74-80.WANG F,WANG W Y.Effect of high temperature creep on the fire resistance of high strengthQ460steel columns[J].Industrial Constructions,2016,46(7):74-80.(in Chinese)
[16]王卫永,何平召.考虑蠕变的约束钢梁抗火性能分析方法[J].重庆大学学报,2017,40(11):65-72.WANG W Y,HE P Z.Approach to analysis fire resistance of restrained steel beams after considering creep effect[J].Journal of Chongqing University,2017,40(11):65-72.(in Chinese)
[17]KODUR V K R,DWAIKAT M M S.Effect of high temperature creep on fire response of restrained steel beams[J].Materials&Structures,2010,43(10):1327-1341.
[18]LUECKE W E,MCCOLSKEY J D,MCCOWAN CN,et al.Federal building and fire safety investigation of the World Trade Center disater:mechanical properties of structural steels[R].Gaithersburg:National Institute of Standards and Technology,2015.
[19]AZPIAZU W,UNANUE J A.Buckling curves for hot rolled H profiles submitted to fire[R].Bilbao:LABEIN,1993.
[20]钢结构设计规范:GB 50017-2017[S].北京:中国计划出版社,2017.Code for design of steel structures:GB 50017-2017[S].Beijing:China Planning Press,2017.(in Chinese)
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