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
| May 25, 2011
Developers push Manhattan office construction
Manhattan developers are planning the city's biggest decade of office construction since the 1980s, betting on rising demand for modern space even with tenants unsigned and the availability of financing more limited. More than 25 million sf of projects are under construction or may be built in the next nine years.
| May 25, 2011
Olympic site spurs green building movement in UK
London's environmentally friendly 2012 Olympic venues are fuelling a green building movement in Britain.
| May 25, 2011
TOTO tests universal design at the AIA conference
If you could be 80 years old for 30 minutes—and have to readjust everything you think you know about your own mobility—would you do it?
| May 20, 2011
Hotels taking bath out of the bathroom
Bathtubs are disappearing from many hotels across the country as chains use the freed-up space to install ever more luxurious showers, according to a recent USAToday report. Of course, we reported on this move--and 6 other hospitality trends--back in 2006 in our special report "The Inn Things: Seven Radical New Trends in Hotel Design."
| May 19, 2011
BD+C’s "40 Under 40" winners for 2011
The 40 individuals profiled here are some of the brightest stars in the AEC universe—and they’re under the age of 40. These young architects, engineers, contractors, designers, and developers stood out among a group of 164 outstanding entrants in our sixth annual “40 Under 40” competition.
| May 18, 2011
Sanford E. Garner on the profitability of being diverse
Sanford E. Garner, AIA, NOMA, LEED AP ND, NCARB, founding partner and president of A2SO4 Architecture, LLC, Indianapolis, on gentrification, the profitability of being diverse, and his goals as NOMA president.
| May 18, 2011
8 Tips for Designing Wood Trusses
Successful metal-plate-connected wood truss projects require careful attention to detail from Building Team members.
| May 18, 2011
Major Trends in University Residence Halls
They’re not ‘dorms’ anymore. Today’s collegiate housing facilities are lively, state-of-the-art, and green—and a growing sector for Building Teams to explore.
| May 18, 2011
Former Bronx railyard redeveloped as shared education campus
Four schools find strength in numbers at the new 2,310-student Mott Haven Campus in New York City. The schools—three high schools and a K-4 elementary school—coexist on the 6.5-acre South Bronx campus, which was once a railyard.
