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
| Oct 25, 2011
MKK participates in BSA Engineering Merit Badge day
MKK principal Craig Watts attended the event as a representative of the MEP (mechanical/electrical/plumbing) engineering industry to give scouts an idea of what’s involved in becoming a mechanical engineer, and an overview of a typical day in the life of an engineer.
| Oct 24, 2011
FMI releases Adjust, Adapt, Act Study
The paper explores several case studies, including Sun Country Builders, Huen, BakerTriangle, Consigli, Skender Construction and Flatiron, and distills the key factors that make these companies unique and successful.
| Oct 24, 2011
BBS Architects & Engineers receives 2011 Sustainable Design Award from AIA Long Island Chapter
AIA LI also recognized BBS with the 2011 ARCHI Award Commendation for the St. Charles Resurrection Cemetery St. Charles Resurrection Cemetery Welcoming and Information Center in Farmingdale, NY.
| Oct 24, 2011
Kolbe adds 3-D models of direct set windows to BIM library?
Beveled Direct Set SketchUp and Revit Models available.
| Oct 20, 2011
UNT receives nation’s first LEED Platinum designation for collegiate stadium
Apogee Stadium will achieve another first in December with the completion of three wind turbines that will feed the electrical grid that powers the stadium.
| Oct 20, 2011
Process leads to new design values for southern pine and other visually graded dimension lumber
A summary of the process used to develop new design values will clarify many of the questions received by the SFPA.
| Oct 20, 2011
Johnson Controls appoints Wojciechowski to lead real estate and facilities management business for Global Technology sector
Wojciechowski will be responsible for leading the continued growth of the technology vertical market, while building on the expertise the company has developed serving multinational technology companies.
| Oct 20, 2011
Stellar hires Navy veteran Taylor as vice president
Stellar’s federal experience includes military exchanges (large retail stores on military bases), lodging facilities for military personnel, fuel stations, youth activities centers and recreational centers.
