火灾后基于偏心距和受火区域为对比因素的钢筋混凝土柱动力损伤识别  

Dynamic Damage Identification of Reinforced Concrete Column Based on Eccentricity and Fire Area after Fire

作　　者：崔文松 高立堂[1] 刘伟[1] 宋来运 CUI Wensong;GAO Litang;LIU Wei;SONG Laiyun(School of Civil Engineering,Qingdao Technological University,Qingdao 266033,China)

机构地区：[1]青岛理工大学土木工程学院,青岛266033

出　　处：《结构工程师》2021年第3期112-120,共9页Structural Engineers

摘　　要：为识别火灾导致的损伤,以偏心距和受火区域作为主要影响因素,对4根钢筋混凝土柱实施振动测试。依据模态试验得到的试件模态参数,分析总结了钢筋混凝土柱受火后动力性能改变程度。对其实施静载试验,得到受火柱相比无损柱的抗弯刚度减小程度和承载力下降幅度。因受压试件存在偏心距,火灾下更易产生裂缝以及损伤的深度更大,造成混凝土的弹性模量和刚度变小。试验结果表明:①由于受压区受火削弱了受压区混凝土高度,同受拉区受火柱相比,受压区受火柱的刚度和极限承载力受火灾的损害更严重。②根据坐标的模态置信准则,钢筋混凝土偏心受压柱的损伤位置可以用其COMAC值精确识别。③钢筋混凝土柱受火后,柱的每阶频率均明显降低,受压区受火柱的频率比受拉区受火柱的频率降低程度大。In order to identify the damage caused by fire,vibration tests were performed on four reinforced concrete columns with eccentricity and fire-affected area as the main influencing factors.Based on the modal parameters of specimens obtained from modal tests,dynamic properties of the reinforced concrete columns subjected to fire were analyzed and summarized.By conducting static load test,bending stiffness and bearing capacity of the column were reduced after being subject to fire.Due to the existence of eccentricity in compression specimens,cracks are more likely to occur under fire and the depth of damage is greater,resulting in a decrease of elastic modulus and stiffness of concrete.The test results show that:(1)as fire weakens the height of concrete in compression zone,stiffness and ultimate bearing capacity of the fire columns in compression zone are more seriously damaged by fire than those in tension zone;(2)according to the modal confidence criterion of coordinates,damage position of the eccentrically loaded reinforced concrete column can be accurately identified by its COMAC value;(3)frequency of the reinforced concrete column in each order is significantly reduced after being subject to fire,and frequency of the column subjected to fire in compression zone is reduced to a greater extent than that of the columm subjected to fire in tension zone.

关 键 词：火灾后 偏心受压柱 损伤识别 动力特性 

分 类 号：TU375.3[建筑科学—结构工程]