施工过程中建筑火灾后结构评估与处理

Structural assessment and treatment of post-fire building under construction

近年来施工过程中火灾频发,与已有建筑火灾相比,施工现场火灾具有不同的特点,即火灾时混凝土多处于较早龄期。针对建筑物施工期间高温火灾致损后的混凝土结构,考虑混凝土较早龄期和不同冷却方式等因素的影响,分析了火灾高温对混凝土和钢材力学性能的损伤情况,并结合具体的工程案例,对施工过程中建筑火灾灾后鉴定评估的关键问题进行了讨论和分析。研究表明,早龄期混凝土火灾后的抗压强度有一定的恢复发展;受火构件的混凝土真实残余抗压强度,宜采用龄期28d后混凝土,并通过钻芯法确定;高温火灾致损后的混凝土结构加固处理,宜保证处理后的结构性能等同于新建建筑。研究结果可为早龄期混凝土结构火灾后的灾害评估和鉴定修复提供一些参考。

In recent years,fires have occurred frequently during construction. Compared with existing building fires,fires on construction sites have different characteristics,that is the concrete is mostly in the early age when it is on fire. In view of the concrete structure after high-temperature fire damage during the construction of the building,considering the influence of factors such as early age of concrete and different cooling methods,the damage of mechanical properties of concrete and steel at high temperature was analyzed. Combined with specific engineering cases,the key issues of post-fire identification assessment of construction fires were analyzed. The results show that the compressive strength of early-aged concrete fires has a certain degree of recovery and development. The actual residual compressive strength of concrete subjected to fires should be determined using drill core method after 28 days of age. The reinforcement of concrete structures after high-temperature fire damage should ensure that the structural performance after treatment is equivalent to that of new buildings. The research results can provide some references for disaster assessment and identification of post-fire structure with early-stage concrete structure.