This state-of-the-art review discusses current research and recent findings on the fire performance of CFS. Further, recent research has taken the first steps towards performance-based design for establishing the fire resistance of CFS structures, including temperature dependence of the material (mechanical and thermal) behavior, thermo-mechanical response of members and sub-systems, and temperature dependence of member strength predictions.

In addition, hot-rolled steel has demonstrated the possibilities and advantages of enabling performance-based fire design (e.g. However, given the wide variety of possible members and details the prescriptive approach has several drawbacks, as discussed in The case for performance-based fire design of cold-formed steel systems section. To date, fire design for load-bearing CFS systems (where the complete structural system is framed from CFS members) has followed the same test-based, prescriptive detail-driven approach that has been previously established for interior partition walls. These prescriptive solutions are critical to current design and represent an important review of the state of the art in their own right however, the focus here is on enabling performance-based fire design, not additional prescriptive solutions. A large number of assemblages have been tested, and industry has assembled catalogs of the prescriptive details that can provide a given fire rating (CFSEI ). The fire-resistance rating is expressed by the number of hours that the assembly can maintain its integrity while containing gases and excessive temperature increases out of the fire compartment. In the United States, the assemblies are required to be вЂњfire-ratedвЂќ (IBC ) based on their ability to withstand a standardized вЂњfireвЂќ test (ASTM ). In a fire, partition walls serve as primary barriers to maintain building integrity, and avoid the spread of fire between compartments (rooms). CFS interior partition walls are framed with studs, have track at top and bottom, and are then sheathed (most commonly) with gypsum wallboard(s). CFS stud and track are used extensively in buildings as the framing for interior partition walls, exterior curtain walls, and more recently as the complete load-bearing system (Allen, Schafer ). The most common members are channels (tracks) and lipped channels (studs and joists).

The review provided here includes experimental results on mechanical and thermal properties of cold-formed steel and temperature dependent constitutive relations, subsystem testing and computational simulations, and analysis models and exploratory methods for fire design, i.e., the building blocks towards performance-based fire design for cold-formed steel systems.Д¬old-formed steel (CFS) members are manufactured from cold bent sheet steel, approximately from 0.5 mm to 3.0 mm thick. Today, engineering knowledge is rapidly advancing, providing the opportunity to contemplate analysis-based design as an enabling tool for general performance-based fire engineering of cold-formed steel systems. However, in fires the performance of cold-formed steel systems are assured by prescriptive detailing and standardized testing. Consequently, design specifications, and structural analysis tools have rapidly evolved to facilitate engineering design of these complex thin-walled members. Cold-formed steel systems have become popular in building construction as both load-bearing and non-load-bearing elements, primarily due to their high strength-to-weight ratio and ease of construction. This paper brings together existing research on cold-formed steel materials, members, and assemblages at elevated temperatures and complementary analysis and design methods necessary for the development of analysis-based design for cold-formed steel systems under fire. Performance-based fire design for cold-formed steel systems is in its infancy.

Aisi cold formed steel framing