Development of an engineering methodology for thermal analysis of protected structural members in fire

Abstract

In order to overcome the limitations of existing methodologies for thermal analysis of protected structural members in fire, a novel CFD-based methodology has been developed. This is a generalised quasi- 3D approach with computation of a "steel temperature field" parameter in each computational cell. The methodology accommodates both uncertainties in the input parameters and possible variants to the specification by means of parallel calculations. A framework for the inclusion of temperature/time-dependent thermal properties, including the effects of moisture and intumescence, has been established. The method has now been implemented as the GeniSTELA submodel within SOFIE RANS CFD code, with initial validation against results from full-scale fire tests. Model sensitivities have been demonstrated revealing the expected strong dependencies on certain properties of thermal protection materials. The code is verified as a generalised thermal analysis tool, with potential to provide a much more flexible means of assessing the thermal response of structure to fire than has been available hitherto.