Experimental Thermal Performance of Unloaded Spiral Strand and Locked Coil Cables Subject to Pool Fires

Abstract

There are no contemporary code requirements for the fire resistance of bridge infrastructure, nor is there guidance available for practitioners who wish to design cable-supported structures for the fire. This research seeks to develop an understanding of the thermal response of steel stay-cables under exposure to a pool fire. Multiple varieties of locked coil and spiral strand stay-cables are instrumented with thermocouples and heated by a methanol pool fire. Novel imaging techniques observe the cables’ surface during heating and cooling and enable the calculation of thermal strains and deformations. Results herein illustrate a normalisation of cross-sectional temperatures outside of the localised heating region for cable diameters up to 140 mm, provide comparisons of heat transfer behaviours for different cable sizes and configurations, present novel thermal rotational effects, and calculation of cable thermal expansion values. Predictive thermal expansion values provided by the Eurocode are shown to underpredict cable thermal expansion in most cases.