论文部分内容阅读
荷载比率、轴向支撑刚度对约束钢梁的性能影响很大,各国学者对其研究主要还集中在升温阶段。对约束钢梁进行了升-降温全过程的承载性能试验,给出了钢梁跨中挠度、轴向支撑应变和柱底水平推力在整个升-降温过程中的变化情况。试验结果表明:钢梁跨中挠度和轴向支撑应变都有不同程度的恢复。泼水冷却过程中也会引起结构或构件的破坏。无支撑或弱支撑情况下,失稳类别为梁端局部失稳;强支撑情况下,失稳类别为梁的整体失稳。同时冷却阶段钢材的强度得到恢复,这对梁的承载能力是有利的;但由于梁的收缩,梁内将产生收缩拉力,加之柱对梁端转动的约束引起的附加弯矩,这些对梁两端的节点是很不利的。基于此,最后从框架节点和钢框架整体两个方面提出了相应的钢框架抗火概念设计建议。
The load ratio and axial support stiffness have great influence on the performance of restrained steel girders. Scholars from various countries mainly focus on the temperature rising stage. The load-carrying performance tests of the restrained steel beam during the entire process of raising and cooling temperature are carried out, and the variations of mid-span deflection, axial support strain, and horizontal thrust of the column during the entire lifting-cooling process are given. The test results show that the mid-span deflection and axial support strain of steel beams are restored to varying degrees. Water cooling can also cause structural or structural damage. In the case of no support or weak support, the instability category is local instability of the beam end; under strong support conditions, the instability category is the overall instability of the beam. At the same time, the strength of the steel in the cooling stage is restored, which is beneficial to the bearing capacity of the beam; but due to the contraction of the beam, the contraction of the tension in the beam will occur, and the additional bending moment caused by the constraint of the column on the rotation of the beam ends. The end of the node is very unfavorable. Based on this, the corresponding suggestions for fire-resistant concept design of steel frame are proposed from the two aspects of the frame node and the steel frame.