火灾下两种不同边界钢筋混凝土双向板的振动性能分析

开展火灾下三边简支一边固支、两短边固支两长边简支两种边界条件下的足尺混凝土板的火灾试验.首先,在双向板表面布置拾振器,对火灾下两种双向板的振动性能进行研究;然后,通过回归分析,提出火灾下双向板的竖向一阶自激励频率与板中竖向位移的关系式,并基于频率差值进行楼板耐火极限预警;最后,采用ABAQUS软件对三边简支一边固支双向板受火过程中的频率差值进行模拟.结果表明:两种边界条件的双向板在火灾作用下的竖向一阶自激励频率均明显降低;频率差值-板中竖向位移的计算值曲线与实测值曲线基本一致.

Vibration Performance Analysis of Reinforced Concrete Two-Way Slab With Two Different Boundaries Under Fire

The fire tests of full-scale concrete slabs with simple support on three sides-fixed support on one side and fixed support on two short sides-simple support on two long sides were carried out. Firstly, the vibration performance of two kinds of two-way slabs under fire was studied by placing vibration pick-up on the surface of two-way slab. Then, through regression analysis, the relation formula between the vertical first-order self-exciting frequency and the vertical displacement in slab under fire was proposed, and the fire resistance limit of floor was predicted based on the frequency difference. Finally, ABAQUS software was used to simulate the frequency difference in the fire process of two-way slab with simple support on three sides-fixed support on one side. The results show that the vertical first-order self-exciting frequencies of two-way slab with two kinds of boundaries reduce obviously under the action of fire; the calculation value curves of frequency difference and the vertical displacement in slab are basically consistent with the measured value curves.