相对两面受火的方钢管钢筋混凝土柱耐火极限

目前有关方钢管钢筋混凝土柱抗火性能的研究主要是针对四面均匀受火的情况,而在实际中,会出现相对两面受火这一情况。为此,利用ABAQUS分析软件建立了方钢管钢筋混凝土柱在相对两面受火作用下高温反应有限元模型,在验证模型正确性的基础上,对其耐火极限进行参数分析,包括荷载比、截面边长、长细比、荷载偏心率、钢材和混凝土强度及配筋率等,得到了相对两面火灾作用下方钢管钢筋混凝土柱耐火极限的主要影响参数和影响规律,并给出了该受火条件下方钢管钢筋混凝土柱耐火极限的简化计算方法。研究结果表明:荷载比、截面边长、长细比是相对两面火灾作用下方钢管钢筋混凝土柱耐火极限的主要影响参数,表现为截面边长越大,荷载比和长细比越小,构件的耐火极限越大。

Fire resistance of bar-reinforced concrete-filled square hollow section columns being exposed to two-opposite-side fire

Previous researches on the fire resistance of bar-reinforced concrete-filled SHS (Square Hollow Section) columns were almost for the cases of that all sides are exposed to fire. However in practice, it is possible that only two opposite sides of the columns are exposed to fire, for which a numerical program is developed to predict the fire resistance of such columns in this paper. Parametric analysis is conducted on the fire resistance of columns, for which the considered parameters include the load ratio, sectional width, slenderness ratio, loading eccentricity, steel and concrete strength, and the steel bar ratio. By simulation analysis the key parameters and their effects are revealed, and a simplified calculation formula for predicting the fire resistance is proposed. The analysis results indicate that the load ratio, sectional dimension and slenderness ratio are the main parameters that influence the fire resistance limit of concrete filled SHS columns, and the fire resistance limit increases with the increase of the sectional dimensions, or with the decrease of the load ratio and the slenderness ratio.