- Author
- Schleich, J. B. | Cajot, L. G. | Pierre, M. | Brasseur, M.
- Title
- Development of Design Rules for Steel Structures Subjected to Natural Fires in Large Compartments. Draft Final Report. July 1, 1993 to June 30, 1996.
- Report
- 7210-SA/210/317/517/619/932, March 1997, 192 p.
- Keywords
- steel structures | compartments | regulations | standards | temperature | temperature fields | thermodynamics
- Identifiers
- does the fire remain localized or not?; temperature of steel elements in case of localized fire; temperature field in the structure; thermo-mechanical behavior; design tool; design example
- Abstract
- The aim of this research is to point out that fire conditions for the large compartments are such that the present fire regulations of the Standards are too severe and to define new requirements which correspond better to the real fire effect. These new requirements have now to be expressed in terms of fire size m2 and Rate of Heat Release [kW]. The procedure developed in the scope of this research enables us to prove that a structure can survive the required fire defined by its size and its Rate of Heat Release. The ISO requirement F30, F90, F120 has been replaced by the requirement "No failure at all", which demonstrates an increase of the SAFETY. A procedure has been developed to check whether the fire is a localised fire and to calculate the temperature field in a steel structure in that case. This procedure implies first a calculation of the air temperature based on a 2 zone models assumption. simplified method and two zone models have been analysed. A important parameter of a 2 zone calculation is the rate of air entrainment which has been studied in details. In a second step, the peak of temperatures produced by the localised fire has been modelised by the Hasemi's method which provides the heat flux distribution. From the heat fluxes, the fire part of the Eurocode 3 has been used to deduce the steel temperature. The validity of the Eurocode formulae to calculate the steel temperature has been checked in case of localised fire. The temperature calculated by that way have been compared with different test results. After determining the steel temperature field the mechanical behaviour is analysed by using the fire part of Eurocode 3. For the column in a 2 zone environment a new formula has been developed. A design tool (spread sheet) called TEFINAF for TEmperature FIeld under NAtural Fire providing the steel temperature field is available.