不同约束方式下钢筋混凝土短柱火灾后(下)力学性能的试验研究
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摘要
为研究钢筋混凝土短柱在相邻构件约束条件下,并经荷载和火灾共同作用后的力学性能,开展了18根受不同约束方式作用的钢筋混凝土短柱火灾后(下)力学性能的试验研究。获得了火灾后(下)钢筋混凝土短柱的剩余承载力、剩余轴压刚度、荷载—轴向变形关系曲线,分析讨论了约束方式、标准升温时间及荷载比等对火灾后钢筋混凝土短柱力学性能的影响。研究结果表明,火灾下和火灾后钢筋混凝土柱试件的破坏模式类似,但后者的混凝土表面裂纹以及剥落较前者严重;不论是火灾下还是火灾后,恒刚度约束的试件破坏较恒荷载约束严重;且恒荷载约束条件下得到的试件耐火极限大于恒刚度约束条件下得到的耐火极限。
To study the behavior of reinforced concrete(RC)stub columns with the restraint of adjacent members under combined loading and fire,18 tests of RC stub columns both under and after fire were conducted.The residual load-bearing capacity,residual axial compression stiffness,and load-axial deformation curves of the tested columns were obtained.Then,the influences of restraint modes,heating time,and load ratio on the behavior of the RC stub columns were analyzed and discussed.The results show that the failure modes of the RC stub columns are similar under and after fire,but surface cracks and spalling are more severe after fire than those under fire.Moreover,the failure of the columns with constant stiffness restraint is more severe than those with constant loading restraint,and the fire resistance of the columns with constant loading restraint is greater than those under constant stiffness condition.
To study the behavior of reinforced concrete(RC)stub columns with the restraint of adjacent members under combined loading and fire,18 tests of RC stub columns both under and after fire were conducted.The residual load-bearing capacity,residual axial compression stiffness,and load-axial deformation curves of the tested columns were obtained.Then,the influences of restraint modes,heating time,and load ratio on the behavior of the RC stub columns were analyzed and discussed.The results show that the failure modes of the RC stub columns are similar under and after fire,but surface cracks and spalling are more severe after fire than those under fire.Moreover,the failure of the columns with constant stiffness restraint is more severe than those with constant loading restraint,and the fire resistance of the columns with constant loading restraint is greater than those under constant stiffness condition.
引文
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[3]吴波,陈书良,张海燕.轴向约束钢筋混凝土异形柱的高温试验研究[J].土木工程学报,2009,42(8):67-74.Wu B,Chen Sh L,Zhang H Y.Experimental study on axial constrained reinforced concrete special-shaped columns[J].China Civil Engineering Journal,2009,42(8):67-74.(in Chinese)
[4]Lie T T,Rowe T J,Lin T D.Residual strength of exposed reinforced concrete columns[J].SP92-9.Detroit:American Concrete Institute,1986,92:153-174.
[5]Schneider U,Morita U T,Franssen J M.A concrete model considering the load history applied to centrally loaded columns under fire attack[C]//Proceeding of4th International Symposium on Fire Safety Science.Ottawa Canada:[s.n.],1994:1101-1112.
[6]吴波,李毅海.轴向约束钢筋混凝土柱火灾后剩余轴压性能的试验研究[J].土木工程学报,2010,43(4):85-91.Wu B,Li Y H.Experimental study on residual axial compression behavior of axially confined reinforced concrete columns after fire[J].China Civil Engineering Journal,2010,43(4):85-91.(in Chinese)
[7]张家广,霍静思,肖岩.高温作用后钢筋混凝土短柱轴压力学性能试验研究[J].建筑结构学报,2011,32(4):117-124.Zhang J G,Huo J S,Xiao Y.Experimental study on properties of reinforced concrete short column pressure shaft after high temperature[J].Journal of Building Structures,2011,32(4):117-124.(in Chinese)
[8]张家铭,陈俊,霍静思,等.火灾升降温模式对高温后钢筋混凝土轴压力学性能影响的试验研究[J].实验力学,2017,32(1):70-78.Zhang J M,Chen J,Huo J S,et al.Experimental research on the influence of fire rising and fall temperature modes on the axial compressive behavior of reinforced concrete after high temperature[J].Experimental Mechanics,2017,32(1):70-78.(in Chinese)
[9]吴波.火灾后钢筋混凝土结构的力学性能[M].北京:科学出版社,2003.Wu B.Mechanical properties of reinforced concrete structures after fire[M].Beijing:Science Press,2003.(in Chinese)
[10]徐玉野,王全凤.火灾后钢筋混凝土柱的剩余承载力研究[J].工程力学,2010,27(2):84-89.Xu Y Y,Wang Q F.Study on residual bearing capacity of reinforced concrete columns after fire[J].Engineering Mechanics,2010,27(2):84-89.(in Chinese)
[11]姜立.不同温度-应力史下混凝土强度和变形的试验研究[D].北京:清华大学,1992.Jiang L.Experimental study on strength and deformation of concrete under different temperature-stress history[D].Beijing:Tsinghua University,1992.(in Chinese)
[12]王志伟.有约束应力高温全过程后钢筋混凝土力学性能试验研究[D].长沙:湖南大学,2012:56-67.Wang Zh W.Experimental study on mechanical properties of reinforced concrete after restrained stress and high temperature[D].Changsha:Hunan University,2012:56-67.(in Chinese)
[13]过镇海,时旭东.钢筋混凝土的高温性能及其计算[M].北京:清华大学出版社,2002:33-49.Guo Zh H,Shi X D.High temperature performance and calculation of reinforced concrete[M].Beijing:Tsinghua University Press,2002:33-49.(in Chinese)