不同加强措施下轴压部分包覆钢-混凝土组合柱抗火性能研究

由于型钢翼缘外露,部分包覆钢-混凝土组合(PEC)柱耐火极限很难满足设计需求。为探究PEC柱抗火性能加强方法,得到经济合理的加强措施,通过ABAQUS有限元分析软件建立了轴压作用下PEC柱的温度场及热力学性能有限元分析模型,并用已有试验数据验证模型可靠性,探讨了PEC柱在高温下的温度变化、受力机理和破坏模式。对不同加强措施下轴压PEC柱抗火性能进行了参数分析,研究了荷载比、纵筋配筋率、翼缘面积比、截面尺寸、长细比和防火涂料厚度等参数对PEC柱耐火极限的影响规律。结果表明:PEC柱耐火极限随荷载比、长细比、翼缘面积比的降低而明显提高,随着防火涂料厚度与截面尺寸的增加而明显提高; 在参数分析的基础上,回归得到考虑防火涂料厚度影响的PEC柱耐火极限简化计算公式,研究结果将为PEC构件抗火设计提供科学依据。

Study on Fire Resistance of Axially Compressed Partially-encased Composite Steel and Concrete Columns with Different Strengthening Measures

Due to the exposed steel flanges, the fire resistance limit of partially-encased composite steel and concrete(PEC)columns is difficult to meet the design requirements. In order to explore the strengthening method of the fire resistance performance of PEC columns and obtain the economic and reasonable strengthening measures, the ABAQUS was used to establish the temperature field and the thermodynamic finite element models of PEC columns under axial compression. The reliability of the model was verified using the existing test data, and the temperature field, stress mechanism and failure mode of PEC column in fire were investigated. The parameter analysis was carried out to study the influence of parameters such as load ratio, longitudinal reinforcement ratio, flange area ratio, section size, slenderness ratio and fireproof coating thickness on the fire resistance limit of PEC columns. The results show that the fire resistance limit of PEC columns will improve with the decrease of the load ratio, slenderness ratio and flange area ratio and the increase of the fireproof coating thickness and section size. A simplified equation is regressed based on the parametric analyses to predict the fire resistance limit of PEC column considering the influence of fire proof coating thickness. The research results will provide a scientific basis for the fire resistance design of the PEC components.