500MPa级钢筋混凝土柱受压区受火性能研究  

Study on fire performance of 500MPa class reinforced concrete column in compression zone

作　　者：刘鑫 高立堂[1] 李晓东[1] 徐丽丽 李自康 Liu Xin;Gao Litang;Li Xiaodong;Xu Lili;Li Zikang(School of Civil Engineering,Qingdao University of Technology,Qingdao 266033,China)

机构地区：[1]青岛理工大学土木工程学院,山东青岛266033

出　　处：《建筑科学》2021年第9期121-129,共9页Building Science

摘　　要：为研究高温后500MPa级钢筋混凝土柱的力学性能,本文共研究11根钢筋混凝土柱,分别对4根未受火试件和7根受火试件进行静力加载试验。火灾试验采用ISO834标准升温过程曲线,同时考虑偏心距和受火时间对试件力学性能的影响。通过试验,得到试件破坏形态以及极限承载力、截面平均应变分布、柱中侧向位移曲线、截面特性。研究表明:①混凝土柱受压区受火后,界限偏心距下的混凝土柱,破坏时由于受拉钢筋未屈服,混凝柱出现由受拉破坏(大偏心破坏)转变为受压破坏(小偏心破坏);②500MPa级钢筋能够和C30混凝土较好地协同工作,通过截面应变的分布可以得到,在平均应变层次上的平截面假定仍适用于火灾后混凝土柱的分析;③火灾后轴心受压柱的破坏形态转变为小偏心受压柱,截面抗弯能力随着偏心距的增加而减小。In order to study the mechanical properties of 500 MPa reinforced concrete columns after high temperature,11 reinforced concrete columns are studied in this paper.4 specimens without fire and 7 specimens under fire of static loading tests are carried out,respectively.The ISO834 standard heating process curve is adopted in the fire test,the influence of loading eccentricity and fire time on the mechanical properties of the specimen is also considered.Through the test,the failure mode,the ultimate bearing capacity of the specimen,the average strain distribution of the section,the lateral displacement curve in column,and the section characteristics are obtained.The research shows that:①After the compression zone of concrete column is under fire,the concrete column under the limit eccentricity changes from tensile damage(large eccentric damage)to compressive damage(small eccentric damage)because the tensile reinforcement does not yield during destruction.②500 MPa-grade steel bars can work well with C30 concrete.Through the distribution of cross-sectional strain,the assumption of a flat section at the average strain level is still suitable for the analysis of concrete columns after fire.③After the fire,the damage form of the axial compression column is transformed into a small eccentric compression column,and the bending resistance of the section decreases with the increase of the eccentricity.

关 键 词：火灾后 界限偏心距 中性轴 火灾后极限承载能力 

分 类 号：TU375.3[建筑科学—结构工程]