ASTM has released a new HSS standard, A1085 - 13 Standard Specification for Cold-Formed Welded Carbon Steel Hollow Structural Sections (HSS), which will result in the production of improved hollow structural sections (HSS). This specification is a big step forward in simplifying HSS design and usage, thereby making it a more desirable option for HSS.
"We were committed to the development of the new ASTM A1085 specification as it was needed to improve the performance of HSS used in structural applications such as seismic load resisting systems, bridge structures and other dynamically loaded structures," said Brad Fletcher, senior sales engineer with AISC-member Atlas Tube. According to Fletcher, round and square members from 6 in. and up will likely be the main shapes Atlas initially produce under the new specification.
Benefits include:
- Tighter material tolerances and a single minimum yield stress of 50 ksi. Because of the more stringent wall tolerances and the addition of a mass tolerance, it's anticipated that AISC's Committee on Specifications will shortly issue guidelines allowing the full nominal wall thickness can be used for design of HSS. This means no longer needing to reduce the nominal wall thickness by 0.93 as prescribed in the AISC Steel Construction Manual for both member selection and connection design. And more area available for design and a higher minimum yield mean that HSS will become a more economical and efficient design option.
- Maximum specified yield stress of 70 ksi. This will result in a lower expected yield strength for seismic design, and thereby reduce capacity design requirements when HSS are the yielding element. For example, with ASTM A1085 HSS braces in a braced frame, the beams and columns will have lower required strengths. ASTM A1085 is the only HSS specification used in North America or Europe that limits the maximum yield stress.
- Standard requirement for notch toughness. The specification will require all HSS to meet a minimum Charpy V-notch (CVN) value of 25 ft-lb at 40°F, which corresponds to AASHTO Zone 2 requirements. Having the minimum CVN required makes HSS more suitable for use in dynamically loaded structures.
"A1085 makes designing with HSS easier and more efficient for both building and bridge construction," said John Simon, vice president of sales with AISC-member EXLTUBE. "We are hearing a great response from structural engineers who have begun to learn about this new spec through efforts at NASCC: The Steel Conference and other communications, and we're working closely with AISC and the Steel Tube Institute to begin promoting A1085 to our customers. EXLTUBE will be supporting these efforts with inventory as soon as we've determined the sizes the market will require from us."
John Tassone, marketing manager for AISC-member Independence Tube, also commented: "We will be manufacturing and inventorying the product as the need arises," adding that the company will likely concentrate on squares and rounds 4 in. and above to start.
For specific price and availability information, please contact HSS producers and service centers. Contact information is available at www.aisc.org/hss.
About the American Institute of Steel Construction
The American Institute of Steel Construction, headquartered in Chicago, is a not-for-profit technical institute and trade association established in 1921 to serve the structural steel design community and construction industry. AISC's mission is to make structural steel the material of choice by being the leader in structural steel-related technical and market-building activities, including: specification and code development, research, education, technical assistance, quality certification, standardization, and market development. AISC has a long tradition of service to the steel construction industry of providing timely and reliable information.
Related Stories
High-rise Construction | Dec 20, 2017
Another record year for high-rise construction
More than 140 skyscrapers were completed across the globe this year, including 15 supertall towers.
Game Changers | Dec 20, 2017
Urban farms can help plant seeds for cities’ growth around them
Urban farms have been impacting cities’ agribusiness—and, on some cases, their redevelopment—for decades.
Market Data | Dec 20, 2017
Architecture billings upturn shows broad strength
The American Institute of Architects (AIA) reported the November ABI score was 55.0, up from a score of 51.7 in the previous month.
Public Health Labs | Dec 19, 2017
10 takeaways from SmithGroup’s ‘lab of the future’ initiative
The LAB2050 initiative digs into the scientific trends, technologies, and economics that will shape tomorrow’s research laboratory environments.
Office Buildings | Dec 19, 2017
How do we measure human performance, and what does it mean for the workplace?
There are many new tools and methods that are beginning to look more comprehensively to evaluate organizational well-being.
Sports and Recreational Facilities | Dec 18, 2017
Canada’s newest funicular makes Edmonton’s largest green space more accessible
The incline elevator is located in downtown Edmonton and was publicly funded.
Sponsored | Building Team | Dec 12, 2017
3 tips to address the top causes of budget overruns
The most cited issues are communication breakdowns, inadequate fees for the work provided, and unrealistic deadlines or schedules.
Multifamily Housing | Dec 12, 2017
Call for technical experts: Dog wash station design
The editors of Multifamily Design + Construction magazine need your expertise.
Government Buildings | Dec 11, 2017
Is this the world’s most humane prison?
The C.F. Møller-designed prison’s architecture supports the inmates’ and staff’s mental and physical well-being.
Architects | Dec 7, 2017
Snow Kreilich Architects receives the 2018 AIA Architecture Firm Award
Julie Snow, FAIA, founded the firm in Minneapolis in 1995, and later was joined by partner Matt Kreilich, AIA.
