基于子结构模型的约束PEC柱抗火性能

Fire performance of restrained PEC columns under axial load based on sub-structure model

利用有限元软件ABAQUS建立了包含部分梁、柱的约束PEC柱子结构温度场和力学分析模型,应用约束PEC柱的抗火试验数据验证了模型的合理性。对轴力作用下子结构在火灾下的受力性能进行了参数分析,分析了轴力比、轴向约束刚度、约束梁跨度、柱长度以及材料强度对子结构轴向位移和轴力的影响规律。结果表明:随着轴力比的增加,柱轴向变形峰值和轴力变化系数峰值减小;随着轴向约束的增加,柱轴力变化系数峰值增大,轴向位移峰值减小,高温压缩阶段的轴向位移趋于平缓;随着柱长度的增加,轴向位移峰值和轴力变化系数峰值略有增加;约束梁跨度、型钢屈服强度和混凝土抗压强度对柱轴向位移和轴力变化系数影响很小。

By using the software ABAQUS,a finite element model was established to calculate the temp erature field and mechanical behavior of the sub-structures including partial beams and retrained PEC columns,then the model was verified by fire test data.The verified model was used to analysis the behavior of the sub-structure subjected to axial load under fire condition,including influence of axial load ratio,axial restraint stiffness,retrained beam span,column length and materials strength on the axial displacement and the axial force.It can be seen from the research results that the axial displacement and the axial force enhancement coefficient decrease due to an increase of the axial load ratio.The increasing of axial restraint stiffness lead to a higher peak value of the enhancement coefficient and lower axial displacement,then the axial displacement reduce gently when the column is compressed.The augment of column length induces a slightly increase in the axial displacement and the axial force enhancement coefficient,while the retrained beam span,steel yield strength,concrete compression strength have little influence.