轴向约束钢筋混凝土柱火灾后剩余轴压性能的试验研究  

Experimental study of the residual axial behavior of axially restrained reinforced concrete columns after fire

作　　者：吴波[1] 李毅海[1] 

机构地区：[1]华南理工大学亚热带建筑科学国家重点实验室,广东广州510640

出　　处：《土木工程学报》2010年第4期85-91,共7页China Civil Engineering Journal

基　　金：国家自然科学基金(50738005;50478078);国家科技支撑计划子课题(2006BAJ03A03-12);教育部新世纪优秀人才支持计划(NCET-04-0819);亚热带建筑科学国家重点实验室重点研究项目(2008ZA10)

摘　　要：实际结构中钢筋混凝土柱在遭受火灾作用时会受到相邻构件的约束作用,其内力在升降温过程中是不断变化的。由于火灾后钢筋混凝土结构经修复加固大多仍可继续服役,积极开展约束柱火灾后的剩余性能研究是必要的。本文进行了16根轴向约束钢筋混凝土柱(方形柱、十字形柱、T形柱和L形柱各4根)标准火灾作用后剩余轴压刚度和承载力的试验研究。研究结果表明:(1)钢筋混凝土柱的剩余轴压刚度随着受火时间的增加逐渐减小;(2)受火时间相同时,钢筋混凝土柱的剩余极限承载力随着初始轴压比的增大而减小,同时随着轴向约束刚度比的增大而增大,最大增幅10%左右;(3)受火时间相同时,柱剩余轴压刚度从大到小依次为十字形柱>T形柱>L形柱;(4)受火时间约90min和110min时,不同试件的承载力折减系数大致分别为0.4～0.5和0.33～0.43。Reinforced concrete （RC） columns would be subjected to restraining effect provided by adjacent structural members when the building is in fire. The internal forces of a heated column may vary during the heating and cooling phases. In most cases, fire-damaged RC structures may still be able to sustain loads when they are repaired and strengthened after fire. Therefore, it is important and essential to study the residual behavior of restrained RC columns after fire. An experimental study was carried out to investigate the residual axial behavior of RC columns after exposed to standard fire. It is found that （1） the longer a column is exposed to fire, the less residual axial stiffness it has after heating and cooling; （2） for RC columns with the same heating time, columns with higher load level tend to have less residual strength than those with lower load level, while columns with higher axial restraint ratio tend to have more residual strength than those with lower axial restraint ratio; （3） for RC columns with the same heating time, the residual axial stiffness decreases in the sequence of ＋-shaped column 〉 T-shaped column 〉 L-shaped column; and （4） the strength reduction factors are about 0.4 -0.5 and 0.33 0.43 for columns with heating time of around 90 min and 110 min, respectively.

关 键 词：钢筋混凝土柱 剩余极限承载力 剩余轴压刚度 火灾后 

分 类 号：TU375.4[建筑科学—结构工程]