大空间建筑火灾下钢索的力学反应参数分析

钢索在大空间建筑火灾升温条件下的力学反应是评价索网结构抗火性能的关键依据。基于非线性有限元方法,建立了钢索在高温下的力学分析模型,模拟了大空间建筑火灾升温历程中钢索力学反应全过程,用参数分析方法得到影响钢索在火灾升温历程中力学反应的关键因素。结果表明:在大空间建筑火灾升温历程中,钢索的水平张力呈下降的趋势;随着钢索的预应力比增加、温度场非均匀性的增强和跨度的增加,其水平张力下降速率增大;荷载比的增加对水平张力下降速率影响较小。上述结论与钢索水平张力的解析解一致,可为索网结构抗火性能分析提供参考。

Parameter Analysis of the Mechanical Behaviours for Steel Cables Exposed to Large Space Fires

The mechanical responses of steel cables exposed to large space fires can be employed to assess fire-resistance feature of the cable network.Mechanical analysis model for steel cable is based on nonlinear finite element method.The model can simulate the mechanical response of steel cable in the history of large space fires.The key factors that affect the mechanical response of cable can be derived from the simulated database using parameter analysis method.The horizontal tension decreases through the whole temperature history and decreases sharply with the increase of prestress ratio,the enhancement of temperature heterogeneity and the elongation of cable span.The horizontal tension depends slightly on the loading ratio.These conclusions agree well with the mathematical solution and can be provided to fire-resistance analysis of cable network.