November 2017


Welcome to ‘Stainless Solutions’ from IMOA. Each month, we will cover a different stainless steel issue with tips on design and specification, and links to technical resources.  This month’s issue focuses on new stainless steel structural design resources.
New Structural Stainless Steel Resources

There are many reasons to use structural stainless steel including its attractiveness, corrosion resistance, fire performance, cyclic loading and energy absorption characteristics (e.g. blast, seismic, impact and similar applications). This article introduces several important new resources that were issued in 2017 for engineers designing with structural stainless steel to either AISC Steel Design Guide 27: Structural Stainless Steel or the Eurocode 3: Design of steel structures - Part 1-4: General rules - Supplementary rules for stainless steels (Eurocode EN 1993-1-4).


New 2017 Eurocode EN 1993-1-4
Design Manual
Eurocode 3: Design of steel structures - Part 1-4: General rules - Supplementary rules for stainless steels (Eurocode EN 1993-1-4) covers all structural shapes from cold formed through larger welded sections. The December 2017 issue of New Steel Construction features an article by Nancy Baddoo of the Steel Construction Institute on the PUREST (Promotion of new Eurocode rules for structural stainless steels) project.

The new Design Manual for Structural Stainless Steel – 4th Edition (2017) (English) was prepared as part of this project. It is in alignment with the 2015 amendment to EN 1993-1-4. The previous editions were comprehensive manuals but the update adds a significant amount of new information including ferritic stainless steel design data, new thermal and mechanical properties of stainless steels in fire, and updated design data and rules. It includes 15 design examples and, in addition to the English download above, will be available in 8 other European languages by the end of 2017.

Eurocode 3 is currently under revision and the new version of EN 1993-1-4 is expected in about 2023. In some areas, the Design Manual provides new rules or design data, which are likely to be included in the next revision. A shaded box explains the difference between these new rules and those currently in EN 1993-1-4:2015.


AISC Steel Design Guide 27: Structural Stainless Steel Design Tables

AISC Steel Design Guide 27: Structural Stainless Steel (2013) is aligned with the 2010 AISC Specification for Structural Steel Buildings. It applies to the design of hot-rolled, extruded and welded open and hollow structural sections (HSS) made from austenitic, duplex and precipitation hardening stainless steel structural sections with a thickness of 1/8 inch or 3 mm and greater. Specification of lighter gauge sections should be done with SEI/ASCE 8-02 Specification for the Design of Cold-Formed Stainless Steel Structural Members.

New 2017 AISC Stainless Steel Structural Design Tables
The Steel Construction Institute has developed a book of design tables to complement AISC Design Guide 27. They are comparable to what is already provided for other structural steels. Minimizing calculations will make it much easier and faster for engineers to design with structural stainless steel.

Design Tables Section headings

  • Explanatory Notes
  • Part 1: Dimensions and Property Tables
  • Part 2: Design of flexural members (Fy = 30 ksi)
  • Part 3: Design of flexural members (Fy = 65 ksi)
  • Part 4: Design of compression members (Fy = 30 ksi)
  • Part 5: Design of compression members (Fy = 65 ksi)

Download the design table book

AISC Webinar for the AISC Design Guide
A live 3-hour webinar on the AISC Steel Design Guide 27: Structural Stainless Steel was recorded in 2014 by Nancy Baddoo and Catherine Houska and is available on AISC’s website. This introduction to the book is an excellent resource for understanding the fundamentals of structural stainless steel selection and structural design relative to other steels.

Structural Stainless Steel Design, Fabrication & Application Resources
The austenitic stainless steels have been most widely used for structural applications, but there is growing use of the higher strength duplex stainless steels. Each stainless steel alloy family provides a wide range of corrosion resistance levels. The property differences between the different stainless steel families and other types of structural steels can be significant. They must be considered during design.

SSINA’s (Specialty Steel Industry of North America) website provides a Comparison of stainless steel alloys identified by alloy designation and UNS (Unified Numbering System used by ASTM) with information on their different High Temperature, Mechanical, and Physical properties. The BSSA (British Stainless Steel Association) website has a Mechanical and Physical Properties section based on the European (EN) alloy numbering system. IMOA has web pages with fabrication information for the Austenitic and Duplex stainless steel families and on Fire and Radiant Heat Transfer.

It is important to note that there are differences between the EN (European Norm) and UNS (Unified Numbering System) chemistry requirements for stainless steel alloy designations.  The specific UNS and/or EN numbers required by a project specification should be listed along with the common names (e.g. 316L or 2205).  These names and numbers appear in standards, code and design guides.

With appropriate selection for the service environment, stainless steel’s unique combination of properties make it a potential solution for solving problems in a diverse range of applications including:

  • Structural applications in water treatment, pulp and paper, nuclear, biomass, chemical, pharmaceutical, food and beverage, and other industries
  • Primary vehicular, rail and pedestrian bridge beams and columns; barriers and guard rails; railings; light and signage poles; cable sheathing; and expansion joints
  • Coastal flood prevention and waterway gate and barrier structures
  • Curtain wall and sunscreen structural supports
  • Street furniture, sculptures, monuments and railings
  • Seismic retrofits and other structural restoration of buildings, structures and bridges
  • Fasteners and anchoring systems in wood, stone, masonry or rock
  • Structural members and fasteners in swimming pool buildings
  • Explosion-, fire- and impact- resistant safety and security related structures such as walls, gates, bollards, and cable ladders and walkways on offshore platforms and other industrial applications


More information about structural design with stainless steel, including research papers and case studies, can be found on these IMOA and SCI websites:

 

Stainless Steel Library

Download a free Stainless Steel Library (zip file, 559 MB) with over 360 pdfs covering building and construction applications, selection, specification, fabrication, sustainability and other common questions.

Stainless Solutions e-newsletter archive

For previous issues or to subscibe to the e-newsletter, please visit the archive page.

Continuing Education – American Institute of Architects (AIA)

IMOA is an AIA continuing education system approved provider with eight 1-hour programs that are registered for both live face-to-face and distance learning credit.

1. Stainless Steel Sustainable Design
2. Bioclimatic Design With Stainless Steel Weather Screens
3. Stainless Steel Structural Design
4. Stainless Steel Specification For Corrosive Applications
5. Deicing Salt: Stainless Steel Selection to Avoid Corrosion
6. Stainless Steel Finish Specification
7. Advanced Stainless Steel Specification and Problem Avoidance
8. Specification of Stainless Steel Finishes and Grades For Corrosive Applications

For more information or to schedule a workshop contact Catherine Houska, 412-369-0377 or email chouska@tmr-inc.com.

What is IMOA?

IMOA (International Molybdenum Association) is a non-profit industry association, which provides technical information to assist with successful specification of molybdenum-containing materials. Molybdenum is an element. When it is added to stainless steel, molybdenum increases its resistance to corrosion caused by deicing salts, coastal atmosphere and pollution.

If you have a topic suggestion for a future issue of Stainless Solutions or need additional technical advice on stainless steel specification and selection, please get in touch here.

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Disclaimer

In providing consultation or other assistance with respect to technical issues, any consultation, assistance or material is provided for the general information of the recipient and should not be used or relied upon for any specific application without first securing competent advice. IMOA and their respective employees, consultants and members (i) make no representation or warranty, express or implied, of any kind with regard to such consultation, assistance or material including no representation or warranty of  suitability for any general or specific use; (ii) assume no liability or responsibility of any kind in connection  therewith; and (iii) disclaim any and all liability for any claim that arises therefrom. 

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