轴向及转动约束对高强纤维混凝土柱抗火性能影响

Influence of axial and rotational restraint on fiber reinforced high strength concrete columns subject to standard fire

为考察轴向及转动约束对高强纤维混凝土柱抗火性能的影响,应用有限元分析软件ABAQUS建立了高强纤维混凝土柱抗火性能分析模型,模型得到了相应试验数据的验证。应用验证后的模型分析了ISO-834标准升温条件下,轴向约束对轴力比、轴向位移及耐火极限的影响,以及转动约束对柱侧向挠度、轴向位移及耐火极限的影响。结果表明:对于轴心受压柱,轴向约束对轴力比及轴向位移有显著影响,但对耐火极限的影响不大。对于偏心受压柱,转动约束对侧向挠度有一定的限制作用,对柱的耐火极限有提高作用。转动约束刚度比小于0.1时,随转动约束的增大,耐火极限总体呈增大趋势。转动约束刚度比大于0.1时,随转动约束的继续增大,柱耐火极限增长不显著,且柱的破坏基本由轴向位移控制。

In order to investigate the influence of the axial and rotational restraint on the fire behavior of fiberreinforced high strength concrete （FRHSC） columns, a numerical model of the fire behavior of FRHSC columnswas developed by the finite element software ABAQUS. The model was verified by the test data and then wasused to analyze the influence of the axial and rotational restraint on the fire resistance deformation and axial forcecoefficients of FRHSC columns under ISO-834 standard fire. Results shows that, for the columns under axialload, the axial restraint has notable influence on P（t）/Po and the axial displacement, but has little influence onfire resistance; for the columns under eccentric load, the rotational restraint can restrict lateral deflections andimprove the fire resistance. When the rotational restraint ratio is less than 0.1, the fire resistance generally in-creases with the increase of the resistance. When the rotational restraint ratio is more than 0.1, the increase ofthe fire resistance is not obvious with the continual increase of the rotational restraint ratio, and the damage ofthe columns is mainly controlled by the axial displacement.