方形钢管混凝土叠合柱三面受火下力学性能分析

A Study on the Mechanical Performance of Square Steel Tube-Reinforced Concrete(ST-RC)Columns Subjected to Three-Side Fire

利用有限元软件ABAQUS建立方形钢管混凝土叠合柱三面受火下的有限元模型,通过现有相关文献试验数据对有限元分析方法的有效性进行验证后,分析方形钢管混凝土叠合柱三面受火下的温度场分布、破坏形态、轴向位移-时间关系、内力重分布、应力、应变等力学性能,并对影响构件耐火性能的相关因素进行参数分析。结果表明,方形钢管混凝土叠合柱三面受火下的横截面温度场分布呈单轴对称形态,荷载比、长细比、柱截面尺寸、外部混凝土抗压强度、截面含钢率是影响构件耐火极限的主要影响因素。基于对各主要参数影响规律的系统分析,提出三面受火下方形钢管混凝土叠合柱耐火极限简化计算公式,为此类构件在该种受火工况下的抗火设计提供参考。

The finite element analysis software ABAQUS was used to build finite element model of a square steel tubereinforced concrete(ST-RC)column under three-side fire condition.After verifying the effectiveness of the finite element analysis method through the simulation of the available experimental results,the mechanical properties such as temperature field distribution,failure mode,axial displacement-time relationship,internal force redistribution,stress and strain development of the square ST-RC column under three-side fire were analyzed,and the related factors affecting the fire resistance of the square ST-RC column were analyzed.The results show that the temperature distribution of the cross-section of the square ST-RC column under three-side fire is in uniaxial symmetrical form.The load ratio,slenderness ratio,column section size,external compressive strength of concrete,sectional steel ratio are the main factors affecting its fire resistance of the square ST-RC column.Based on the systematic analysis of the influence rule of each main parameter,a simplified formula for calculating the fire resistance of the square ST-RC column under three-side fire is presented,which provides a reference for the fire resistant design of this kind of component under the fire condition.