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为研究钢梁-柱节点的力学性能和承载力进行耐火试验。当遭受火灾时,结构沿厚度方向形成热梯度。在密歇根州立大学实验室熔炉中进行了宽翼缘试件的轴向受力试验。通过绝缘处理模拟了三面受热的实际工况,如框架周边柱。以荷载水平、火情、热梯度方向(受弯方向)为参数,进行多组试验。在轴力P和弯矩M共同作用下,试件发生全截面屈服破坏,不同参数组合对试件的耐火性能有重要影响。由于厚度方向的热梯度,柱弯矩相应增大;而由于截面弯曲中心的变化,弯矩减小。热梯度同样影响轴力和弯矩组合塑性抵抗矩,如沿柱长度最热处的临界截面,此处弯矩最小(并不是直观认为的最大值)。试验与计算模型在预期要求(如弯矩减小)和承载力(如塑性P-M承载力变化)方面吻合很好。
In order to study the mechanical properties and bearing capacity of steel beam-column joints, fire resistance test was carried out. When subjected to a fire, the structure forms a thermal gradient in the thickness direction. The axial stress test of wide flange specimens was carried out in a Michigan State University laboratory furnace. Insulation process simulation of the actual working conditions of three sides, such as the frame around the column. The load level, fire, thermal gradient direction (bending direction) as a parameter, a number of groups of tests. Under the joint action of axial force P and bending moment M, the full cross-section yield failure occurs in the specimen, and the combination of different parameters has an important influence on the fire resistance of the specimen. Due to the thermal gradients in the thickness direction, the column bending moment increases correspondingly, while the bending moment decreases due to the change of the bending center of the section. The thermal gradient also affects the combination of axial force and bending moment plastic moment of resistance, such as the hottest critical cross-section along the length of the column where the moment is minimal (not the maximum visually perceived). The experimental and computational models agree well with the expected requirements (such as reduced bending moment) and bearing capacity (such as changes in P-M bearing capacity).