Designing stainless steel structures is going to get a lot easier!

The development of the first U.S. design specification for hot rolled, welded and hollow structural stainless steel sections is well underway and will be published in 2021.

Currently there is no U.S. stainless steel design specification for mainstream structural sections such as welded, hot rolled or hollow sections, which are the majority of the market. As a first step to remedying this situation, the American Institute of Steel Construction (AISC) commissioned Nancy Baddoo of the UK’s Steel Construction Institute (SCI) to write an AISC Design Guide on structural stainless steel, DG27, which was published in 2013. The interest in this guide led to AISC deciding in 2018 to develop a full design specification for structural stainless steel.

At the same time, the American Society of Civil Engineers (ASCE) started a major update of ASCE 8  which covers the design of cold-formed stainless steel sections, and had not been revised for more than 20 years. This specification is geared towards lighter gauge products, such as channels and angles and structural components in transit vehicle framing.

Both the AISC and ASCE work on the specifications is overseen by technical committees which are made up of structural designers, academics, fabricators, metallurgists, and representatives from stainless steel producers. SCI has led the drafting of the AISC specification, working closely with Catherine Houska and John Grubb (ATI) on metallurgical and fabrication issues. Their work has been funded by an industry consortium including Outokumpu, Industeel, New Castle Stainless, Stainless Structurals, Stalatube, Nickel Institute, International Molybdenum Association, International Stainless Steel Forum and AISC.

The last two years have involved intense activity developing design rules, aiming to find the right balance between economy and ease of use. Following a number of ballots and public review drafts, the drafting of both stainless steel design specifications is nearing completion with publication expected in 2021. An accompanying AISC Design Guide will also be published in 2021 with comprehensive guidance on alloy selection to avoid corrosion. The Design Guide will include design tables to simplify and speed up design, as well as informing designers of the range of section shapes and sizes.

The availability of these two complementary, up-to-date, and user-friendly design specifications will remove significant long-standing obstacles for structural stainless steel designs. The stainless steel industry will benefit directly from increased specification, and the benefit will be not limited to the U.S. since these specifications are used globally. Furthermore, the benefits are not limited to buildings and construction: it is likely that stainless steel rules for nuclear facilities and bridges will follow.