The development of generic span tables for cold formed steel studs in residential and low-rise construction

The process of roll forming of steel provides the designer with virtually unlimited possibilities in the shape of the section which has led to the development a wide range of very efficient proprietary sections. However this has made it difficult for building designers and engineers to design and specify a house or other low-rise structure given the number of different sections available and complexity of the cold-formed steel standard AS/NZS 4600. The sections commonly used in Australia and America were reviewed and a wide range of sections were chosen to cover the range of sections commonly used. They covered lipped and plain C channels made from G300 and G550 steel. These sections were investigated to determine their load carrying capacity. Factors evaluated included effective lengths for both clad and unclad studs, width of studs, height of walls, connection types, and influence of noggings. From this analysis a standard stud was chosen which was specified in tenns of load capacity rather than section shape and thickness. This allows manufacturers to develop innovative new sections for which the span tables permit valid selection. It also allows last minute changes and substitutions to be made on site simply and quickly. The load combinations are determined from the NASH Standard - Residential and Low-rise Steel Framing Part 1 Design Criteria. The critical load cases are identified and discussed. Examples of the resulting span tables are given together with typical installation details