火灾后钢筋混凝土梁基于振型曲率差损伤识别应用研究  

Damage identification study of reinforced concrete beam after fire based on mode curvature difference

作　　者：朱玲玲 陈静茹[1] 高立堂[1] 许盼让 Zhu Lingling;Chen Jingru;Gao Litang;Xu Panrang(College 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5期143-149,共7页Building Science

摘　　要：在火灾安全事故中,建筑物的梁式构件损伤较为严重。梁作为主要承载的水平构件,对其进行合理的损伤识别尤为重要。本文选用5根钢筋混凝土梁进行火灾前后动力试验研究。为简化分析,突出主要因素,采用底部单面受火。通过分析火灾前后的固有频率、振型及振型曲率差,研究梁损伤状态,并给出相应的判别依据;同时,使用ABAQUS软件对试验结果进行验证。结果表明:火灾后的频率比因试件内部材料性能受到损伤而发生变化、火灾前后振型变化不大,因此频率、振型均不能对梁的损伤进行有效判定;振型曲率差在损伤位置处发生突变,对损伤状态特别敏感,尤其是高阶振型。因此,使用振型曲率差对损伤进行识别有助于合理判定火灾后钢筋混凝土梁的安全状态。In the process of fire accident,normally the damage of beam members in the building is serious. As the main bearing horizontal member,it is very important to identify the damage reasonably. In this paper,5 simply supported reinforced concrete beams are selected for post-fire dynamic test. In order to simplify the analysis and highlight the main factors,the fire on single side of beam bottom is applied. By analyzing the natural frequency,vibration shape and curvature difference of beam before and after fire,the damage state of beam is studied and the corresponding discriminant basis is given. At the same time,the test results are verified by finite element analysis.The results show that the frequency ratio changed after fire due to the damage of the material inside the specimen and vibration mode does not change much before and after the fire. Therefore,the damage of beam cannot be effectively determined by frequency and mode. And the curvature difference of vibration mode is particularly sensitive to the damage state,especially the high order mode. It is helpful to determine the safe state of reinforced concrete beams after fire by using mode curvature difference.

关 键 词：钢筋混凝土梁 损伤识别 振型曲率差 应用研究 

分 类 号：TU375[建筑科学—结构工程]