不同受火边界下装配式框架的节点抗火性能研究

Study on Fire Resistance of Assembled Frame under Different Fire Boundary Conditions

采用ABAQUS有限元分析软件建立装配式框架中节点上部和下部受火的分析模型,分析重要截面的温度场分布,并将耐火极限的计算值与试验值进行对比验证。研究一定参数范围内荷载比、配筋率、线刚度比对构件耐火极限的影响。研究表明:在不同的受火条件下,梁端变形在升温起初变化缓慢,而接近耐火极限时变形加快,破坏具有一定的突然性。荷载比对节点的耐火极限影响较为显著,表现为荷载比越大,耐火极限越小;配筋率增大时,节点耐火极限变小;随着线刚度比变大时,耐火极限变大。不同受火边界对中节点的耐火极限有一定的影响,两者耐火极限相差0.03%。在相同荷载比、配筋率、线刚度比条件下,上部受火节点耐火极限较下部受火耐火极限小。

Based on the finite element analysis software ABAQUS, the analysis model of the upper and lower part of the assembled joint subjected to fire is established, and the temperature field distribution of the important section is analyzed, and the calculated value of fire resistance is compared with the test value. The influence of load ratio, reinforcement ratio and linear stiffness ratio on the fire resistance of members is studied. The results show that: under different fire conditions, the deformation of the beam end changes slowly with the heating time at first, and accelerates when it approaches the fire resistance limit. The results show that the greater the load ratio is, the smaller the fire resistance limit is;when the reinforcement ratio is increased,the fire resistance limit of the joint decreases, and with the increase of the linear stiffness ratio, the fire resistance limit increases. Different fire boundaries have certain influence on the fire resistance of the joints,and the difference between them is 0.03%. Under the same load ratio, reinforcement ratio and linear stiffness ratio, the fire resistance of the upper part is smaller than that of the lower part.