钢索在火灾升温历程中瞬态张力的解析计算方法

MATHEMATICAL CALCULATION OF INSTANTANEOUS TENSION FOR STEEL CABLES IN FIRE TEMPERATURE HISTORY

  • 摘要: 该文根据常温下单索的基本平衡微分方程,建立了钢索在高温材性非线性衰减、非线性热应变以及几何形变耦合状态下的微分方程组;分别求解出受均布荷载和集中荷载作用的钢索,在均匀和非均匀温度场中其水平张力的非线性瞬时计算式,并提出了判断钢索高温极限承载力的力学计算方法;同时用解析计算方法验证了基于非线性有限元方法建立的单索热力耦合计算模型的精确性,为进一步研究索网结构的整体抗火性能奠定了理论 基础。

     

    Abstract: Based on the equilibrium differential equation of cable at ambient temperature, considering the geometric distortion with thermal stress coupling, the temperature distribution along cables and the non-linear temperature-dependent material properties for steel cables, formulas for the calculation of horizontal tension in cables subjected to fire under line loads and point loads are developed. In the mean time, the fire limit state of steel cables is derived from the equation of horizontal tension. Additionally the nonlinear numerical model for the analysis of the cable fire performance is fit to the analytical calculation precisely. This study provides a theoretical reference for a further research on the fire-resistance of cable structures.

     

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