钢筋混凝土柱缩尺模型明火试验及耐火性能尺寸效应研究

目前混凝土结构耐火试验研究主要针对单根足尺构件，难以体现构件间的相互影响。要将研究从构件层次提升到结构层次，开展缩尺模型试验是必经之路，但火灾下缩尺模型与足尺原型热-力响应间的相似关系构建一直未能有效解决。为此，本项目将开展不同尺寸混凝土圆柱体的高温受压试验以及不同比例钢筋混凝土轴压柱的明火试验，在通过控制实验炉的升温曲线，确保缩尺模型和原型柱温度场相似（对应时点、对应位置的温度相等）的前提下，考察钢筋混凝土柱高温力学性能的尺寸效应；然后建立钢筋混凝土柱的三维细观数值模型，开展更大尺寸柱的耐火性能数值模拟分析。基于试验及数值模拟分析结果，构建火灾下缩尺模型和原型柱结构响应间的相似关系，进而提出采用钢筋混凝土柱缩尺模型明火试验结果预测原型柱耐火极限的方法。本项目的顺利进行将有助于突破结构抗火领域研究主要停留于单根足尺构件的局限，从而推动研究从构件层次向结构层次迈进，进而提升结构的火灾安全性。

In the research field of fire resistance for concrete structures, fire tests are commonly conducted on single full-scale component, but these tests cannot reflect the interaction between components. To upgrade the research level from components to structures, fire tests have to be conducted on scale models. However, there is a lack of similarity relationship in thermal-mechanical response between reduced-scale model and full-scale prototype in fire. In this project, axial compression tests are to be conducted on concrete cylinders with different sizes at elevated temperatures, and fire tests are to be done on reinforced concrete columns with different scales. The size effect on high-temperature mechanical properties of reinforced concrete columns will be investigated, on the condition that the internal temperature distributions in the scale model and the prototype column attain good similitude, through controlling the temperature-time curves of the furnace. The fire resistance of reinforced concrete columns with larger sizes are to be analyzed through numerical simulation on the three-dimensional meso-scale models. Based on the results from fire tests and numerical simulation analysis, the similarity relationship of the structural responses in fire between the scale model and the prototype column can be established. As a consequence, a method for predicting the fire endurance of the prototype column, by using the data from fire test on the reduced-scale model of reinforced concrete column, will be proposed. The successful implementation of this project will help to break through the limitation that the fire test object is limited to a single component, so as to promote the research in structural fire resistance from component level to structural level, and thus enhance the fire safety of structures.