内配圆钢管的 SRC 短柱耐火极限分析

摘要

A nonlinear finite element model was developed to analyze the fire resistance of SRC (steel reinforced concrete ) columns with inner circular steel tube subject to the around‐face heating ,which was validated by a number of experiment results of concrete shaped columns .On the basis of the program ,parametric analysis of the fire resistance limit of SRC columns with inner circular steel tube was conducted ,and 115 hypothetical cases were analyzed for various parameters ,including the load ratio ,sectional perimeter ,slenderness ratio ,loading eccentricity and the area ratio of steel inner concrete .Key parameters and their effects were obtained from the simulation results ,and a simplified calculation formula for predicting the fire resistance limit was given .The analysis results indicate that the load ratio ,sectional perimeter and slenderness ratio are main parameters that influence the fire resistance limit of SRC columns with inner circular steel tube columns ,and the fire resistance limit increases with the increase of the sectional dimensions and with the decrease of the load ratio and the slenderness ratio .The simplified calculated method in this paper can be used as a reference of fire resistance design of SRC columns .%建立了四周受火的内配圆钢管S RC短柱抗火分析有限元模型，采用大量耐火试验数据验证模型的合理性，对不同荷载比、截面周长、长细比、荷载偏心率及含钢率共115种工况下耐火极限进行参数分析，得到了内配圆钢管S RC短柱耐火极限的主要影响参数及其影响规律，在此基础上，回归出内配圆钢管S RC短柱耐火极限简化计算公式。研究结果表明：影响内配圆钢管S RC短柱耐火极限数值的重要因素有荷载比、截面周长和长细比，具体表现为耐火极限与截面尺寸呈正相关，与荷载比和长细比呈负相关；该耐火极限简化计算公式可供实际工程参考。