Effect of embedded steel stirrups on fire behavior of square steel tubular columns filled with recycled lump concrete
Effect of embedded steel stirrups on fire behavior of square steel tubular columns filled with recycled lump concrete
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DOI：
10.1016/j.engstruct.2020.110446
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发表时间：
2020-05
影响因子：
5.5
通讯作者：
Bo Wu;Jian Zang
中科院分区：
文献类型：
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作者：
Bo Wu;Jian Zang
钢管柱填充再生混凝土块（RLC）制成的拆除混凝土块（DCLs）和新鲜混凝土（FC）已被证明在室温下具有良好的力学性能，但这种柱的防火性能仍然知之甚少。本文对七根足尺方钢管柱进行了RLC填充和FC填充的火灾试验研究。试验中考虑的参数包括DCL的取代率、钢管内的钢箍筋及其布置、钢管与钢箍筋之间的净距离。有箍筋的柱与无箍筋的对照柱具有相同的钢总量。试验结果表明：（1）在配筋率达到25%时，DCL对柱的抗火性能影响不大;（2）与无箍筋柱相比，配筋柱的抗火性能显著提高（高达178%），而不增加总的用钢量，由于温度屏蔽钢箍筋对内部混凝土核心的限制作用;（3）在某些情况下，不需要任何外部防火涂层就可以达到超过180 min的耐火极限。将EN 1994-1-2：2005中规定的简单计算方法推广到预埋箍筋柱的耐火极限计算中。
Steel tubular columns filled with recycled lump concrete (RLC) made of demolished concrete lumps (DCLs) and fresh concrete (FC) have been shown to have good mechanical properties at room temperature, but the fire performance of such columns has remained poorly understood. This study presents an experimental investigation on the fire behavior of seven full-scale square steel tubular columns filled with RLC or with FC alone. The parameters considered in the fire tests included the replacement ratio of DCLs, the steel stirrups inside steel tube and their arrangement, and the clear distance between the tube and steel stirrups. The columns with stirrups have the same total amount of steel as the control column without stirrups. The test results show that: (1) including DCLs up to a replacement ratio of 25% has little effect on a column’s fire resistance; (2) compared with a columns without steel stirrups, columns with embedded stirrups have significantly enhanced fire resistance (by up to 178%) without increasing the total steel usage, due to the confining effect of the temperature-shielded steel stirrups on the inner concrete core; and (3) fire resistance exceeding 180 min can be achieved in some cases without any external fire retardant coating. The simple calculation method specified in EN 1994-1-2:2005 is extended to predict the fire resistance of columns with embedded stirrups.