板角约束混凝土双向板抗火性能试验研究

Fire test on two-way concrete slab under corner restraint

为研究混凝土双向简支板板角受平面外约束下的火灾行为,进行了恒载-升温条件下的火灾试验。采用无线测温技术和红外探测技术,获得了火灾下双向板沿板厚温度场分布、钢筋温度、板平面内外变形、裂缝以及板角平面外约束力变化,并与国内外相关试验进行对比分析。测试结果表明:自行设计无线测温设备测量精确度较高,且便于使用;红外探测技术能够实时记录板面裂缝发展。分析结果表明:当板角受平面外约束时,其裂缝模式及变形规律与四边简支板明显不同;且板角区域易出现弧形裂缝,板角约束程度对板角区域弧形裂缝分布与发展有显著影响。

In order to analyze the fire behavior of the two-way concrete slab with out-of-plane restraints on comers under constant loads, one fire test which includes the wireless temperature measurement and infrared detection was conducted to obtain the temperature field along the depth, the reinforcement temperature, the out-of-plane and in- plane deflection, crack and the corners＇ out-of-plane restraint reaction. The test results also were compared with the relevant tests at home and abroad. Results indicate that the wireless measurement could get high-accuracy results with easy use, and the infrared detection technology can have a real-time observation on the slabs＇ cracks. The cracking pattern and deflection of the slab with out-of-plane restraints on the comers is clearly different from those of the simply support slabs, and arc-shaped cracks easily occurred near to slabs＇ comers. The corners＇ restraint degree has a considerable effect on the arc-shaped crack distribution and development of the slabs＇ comers.