Experimental investigation and numerical analysis on fire response of parallel-wire cable exposed to open-air fire

Abstract

This paper presents experimental and numerical studies on fire behaviors of a parallel-wire cable subjected to an open-air fire and applied tension. A novel fire resistance test of cable was designed for observing mechanisms of fire propagation and structural deformation; subsequently, a numerical method is established for evaluating corresponding fire behaviors of the cable exposed to the pool fire. The experimental results showed that, a coupling fire of pool fire and cable surface fire could occur; the sheath sequentially provided the insulation effect in the pre-ablation and combustion-supporting effect in the post-ablation; thermal conductivities in the radial and axial directions of the wire bundle differed; and deformation of the cable was characterized by three stages. The numerical results illustrate that, the established method can successfully reproduce the fire behaviors from the fire’s feature to the cable’s performance; a failure signature of the loaded cable exposed to the pool fire can be captured. In addition, the numerical method is utilized for analyzing fire resistance limits of cables with different fire scenarios, surface layer states, section diameters, and degrees of prestressing. The acquired experimental measures and the established numerical method contribute experience and access to fire behavior research of cable, respectively.