PEC柱在自然火灾下耐火性能的影响因素分析

Parametric Study on Fire Behavior of PEC Column Based on Nature Fire

自然火灾的温度曲线包括升温段和降温段曲线,其中降温段的温度作用对结构的耐火性能有重要的影响。为了深入的分析这种影响,文章基于ABAQUS软件建立了部分包裹混凝土(Partially Encased Concrete,简称PEC)柱在自然火灾作用下的有限元模型。通过PEC柱在自然火灾下的轴向位移-时间曲线,截面温度-时间曲线等关系,分析了截面尺寸、火灾荷载比、长细比对PEC柱在自然火灾下耐火性能的影响。结果表明:PEC柱的破坏可能出现在自然火灾的升温段,也有可能出现在降温段;火灾荷载比和构件长细比的增大导致PEC柱耐火性能减弱,截面尺寸对PEC柱耐火性能的影响很小。

The temperature curve of the natural fire includes the heating and cooling phases, the cooling section has an important effect on the fire resistance of the structure. In order to analyze this effect in depth, a finite element model of Partially Encased Concrete（PEC） column under natural fire is established by using ABAQUS software. The axial displacement-time curve, cross-section temperature-time curve of the PEC column under natural fire were using to analyze the influence of cross section size, fire load ratio and slenderness ratio on the fire resistance of PEC column under natural fire. Results show that PEC column damage may occur in the natural fire of the heating section, or in the cooling section; The fire load ratio and the increase of the slenderness ratio of the component result in the weakening of the fire resistance of the PEC column, and the cross-sectional dimension has little effect on the fire resistance of the PEC column.