带保护层方钢管混凝土柱耐火极限的试验研究

TESTS ON THE FIRE RESISTANCE CONCRETE FILIED STEEL SQUARE TUBULAR COLUMNS WITH PROTECTIONS

通过对３个方钢管混凝土柱按１９１８３４和ＧＢ９９７８－８８规定的标准升温曲线升温作用下耐火极限的试验，研究带保护层情况下方钢管混凝土柱的耐火性能和耐火极限。试验研究结果表明，火灾下方钢管混凝土柱的性能和圆钢管混凝土柱类似。由于钢管和混凝土的共同工作，且核心混凝土具有较好的吸热性能，从而使方钢管混凝土柱具有较好的耐火性能，在柱子外围只需进行适当的防火涂料保护，即可达到《ＧＢ５００４５－９５高层民用建筑设计防火规范》对柱结构所要求的耐火极限。分析结果还表明，钢结构柱防火保护层厚度的确定方法，不适合于方钢管混凝土柱。研究成果可为有关方钢管混凝土工程防火设计提供参考。

Three large-scale concrete filled steel tubular columns were tested under Standard Fire Curve, the behavior and the fire resistance of the columns are studied. The experimental results in this paper show that the behavior of concrete filled steel tubular columns with square sections under fire are similar to that of columns with circular sections. The square composite columns have excellent behavior under fire and high fire resistance because of the interaction between the steel tube and its core concrete, as well as the heat absorption ability of the concrete core itself. The columns can satisfy the design fire resistance that are demanded by the code named < GB50045-95 Code for Fire Protection of High-Rise Building > with proper spraying material protection, the fire protection thickness determination methods for pure steel structure columns are unsuitable for the composite columns. The achievements in this paper may be reference for the fire protection design of practical engineering with concrete filled steel tubular coltumns with square sections are used.