Cold-formed steel
**History and Development of Cold-Formed Steel**:
– Cold-formed steel use began in the 1850s in the US and Great Britain.
– Limited acceptance in the 1920s and 1930s due to lack of design standards.
– First documented use at the Virginia Baptist Hospital in the 1920s.
– AISI published the first design standard in 1946.
– Lustron Homes sold 2500 steel-framed homes in the 1940s.
– AISI design standards evolved from the 1930s to the 1990s.
**International Codes and Standards**:
– North American Specification for Cold-Formed Steel in the US, Mexico, and Canada.
– Eurocode 3 used in EU nations.
– Various nations base their standards on AISI guidelines.
– Specific codes like EBCS-1 and EBCS-3 in Ethiopia.
– Different countries have their own national standards.
**Regional Applications and Standards**:
– US and Canada have specific codes like AISI S100 and CAN/CSA S136-07.
– Asia (Philippines, India, China, Japan, Malaysia) and their respective standards.
– European countries use Eurocode 3 and national annex documents.
– Oceania (Australia, New Zealand) follows AS/NZS 4600.
**Properties and Characteristics of Cold-Formed Steel**:
– Lightness, high strength, and ease of prefabrication.
– Termite-proof, non-combustible, and recyclable.
– Variety of shapes, grades, and properties used.
– Yield stress ranges from 33ksi to 80ksi.
– Modulus of Elasticity ranges from 29,000 to 30,000 ksi.
**Construction Techniques and Applications**:
– Cold-formed steel commonly used in light-frame building construction.
– Applications in floors, roofs, walls, residential, commercial, industrial, and infrastructure projects.
– Advantages include high strength-to-weight ratio, fire resistance, durability, sustainability, and cost-effectiveness.
– Various connectors and fastening methods are crucial for performance.
– Alternative design methods like DSM provide optimization and accuracy.
The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (December 2010) |
Cold-formed steel (CFS) is the common term for steel products shaped by cold-working processes carried out near room temperature, such as rolling, pressing, stamping, bending, etc. Stock bars and sheets of cold-rolled steel (CRS) are commonly used in all areas of manufacturing. The terms are opposed to hot-formed steel and hot-rolled steel.
Cold-formed steel, especially in the form of thin gauge sheets, is commonly used in the construction industry for structural or non-structural items such as columns, beams, joists, studs, floor decking, built-up sections and other components. Such uses have become more and more popular in the US since their standardization in 1946.
Cold-formed steel members have been used also in bridges, storage racks, grain bins, car bodies, railway coaches, highway products, transmission towers, transmission poles, drainage facilities, firearms, various types of equipment and others. These types of sections are cold-formed from steel sheet, strip, plate, or flat bar in roll forming machines, by press brake (machine press) or bending operations. The material thicknesses for such thin-walled steel members usually range from 0.0147 in. (0.373 mm) to about ¼ in. (6.35 mm). Steel plates and bars as thick as 1 in. (25.4 mm) can also be cold-formed successfully into structural shapes (AISI, 2007b).