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通过对端部约束H型钢柱火灾响应及火灾后力学性能的对比试验研究,分析了不同约束条件对H型钢柱火灾行为及受火后力学性能的影响。试验测定了钢柱的温度响应及位移响应,在此基础上进一步开展了火灾后的力学性能试验。结果表明:钢柱在升温和降温过程中存在一定的滞后性,火灾升温时柱顶位移按自由膨胀、对称约束及不对称约束依次减小;约束性质对火灾后H型钢柱的力学性能有明显的影响,对称约束的H型钢柱在火灾后的应变明显不同于非对称约束的情况,而且非对称约束钢柱压曲破坏前的整体刚度明显高于对称约束;无约束H型钢柱受火后的整体屈曲主要沿弱轴方向弯曲,而约束H型钢柱受火后的整体受压屈曲则沿两个方向均有明显的侧向弯曲,且沿弱轴方向的受压曲线基本呈三角形,绕强轴方向则为S形。
Through the comparative experimental study on the fire response and post-fire mechanical properties of H-beam confined by the end, the influence of different constraints on the behavior of fire and the mechanical properties of H-beam were analyzed. The temperature response and the displacement response of the steel column were measured. Based on this, the mechanical properties of the steel after fire were further tested. The results show that there is some hysteresis in the process of temperature rise and temperature drop of the steel column. The displacement of the column top expands freely when the fire temperature rises, and the symmetric and asymmetric constraints decrease in sequence. The restraining property has obvious effect on the mechanical properties of the H- , The symmetry constrained H-shaped steel columns obviously differ from the asymmetrical ones after fire, and the overall stiffness before the buckling of the asymmetrically restrained steel columns is obviously higher than that of the symmetrical restraints. After the unconfined H-beams are exposed to fire The overall buckling of the H-beam is mainly along the direction of the weak axis, while the overall buckling of the constrained H-beam after the fire has obvious lateral bending in both directions and the compression curve along the direction of the weak axis is basically triangular, Strong axis direction is S-shaped.