Performance-based fire resistance design method for wall panel assemblies using thin-walled steel sections

The advantages of cold-formed thin-walled steel studs are many and their application in building construction continues to grow. They are used as loadbearing members. An example is lightweight wall panel assemblies which consist of channel steel studs with gypsum plasterboard layers attached to the two fl anges, often with interior insulation. At present, expensive fi re tests or advanced numerical modelling methods are necessary in order to obtain the fi re resistance of such wall assemblies. For common practice this is not eff ective and a simplifi ed method, suitable for use in daily design, is necessary. This paper explains a new approach for calculating key temperatures on the steel studs and describes the Direct Strength Method (DSM) for calculating the load-bearing capacity of cold-formed thin-walled steel studs with nonuniform temperature distributions in the cross-section, instead of using the traditional eff ective width method. Combining these two aspects gives a performance-based fi re resistant design method that can be used in the design or development of products.