火灾下钢-混凝土组合楼盖的声发射监测及分析

Acoustic Emission Monitoring and Analysis of Steel-Concrete Composite Floor Under Fire

为研究火灾下钢-混凝土组合楼盖的损伤机理,利用声发射技术对组合楼盖不同位置处的声发射信号进行监测.通过声发射系统采集的振铃计数、幅值、能量和持续时间等基本参数,结合试验宏观现象,对声发射进行振铃计数分析、RA-AF关联分析和b值-能量分析.研究表明:根据振铃计数信号,可判断构件的裂缝开展密集程度及内力变化,在降温阶段,次梁会对钢筋混凝土板产生剪切裂缝,使结构产生二次破坏;RA-AF关联分析能准确地判断出组合楼盖的失效模式,可根据其失效模式进行相应的内力分析;b值-能量分析可反映出试件破坏时的能量变化及试件的损伤程度,并推断出构件是否达到相应的破坏状态.

To study the damage mechanism of steel-concrete composite floor under fire,an acoustic emission technology was used to monitor the acoustic emission signals at different positions of the composite floor.The basic parameters such as ringing count,amplitude,energy and duration collected by the acoustic emission system,combined with the experimental macroscopic phenomenon,ringing count analysis,RA-AF correlation analysis and b value-energy analysis were conducted for acoustic emission.The research shows that according to the ringing count signal,the cracks of the members and internal force changes can be judged;in the cooling stage,the secondary beams produces shear cracks on the reinforced concrete slabs,causing secondary damage to the structure;RA-AF correlation analysis can accurately determine the failure mode of the composite floor,and the corresponding internal force can be analyzed according to the failure mode;the b value-energy analysis can reflect the energy change of the specimen and the damage degree of the specimen,and infer whether the member has reached the corresponding damage status.