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
| Jul 10, 2013
TED talk: Architect Michael Green on why we should build tomorrow's skyscrapers out of wood
In a newly posted TED talk, wood skyscraper expert Michael Green makes the case for building the next-generation of mid- and high-rise buildings out of wood.
| Jul 9, 2013
Where are they now? 40 Under 40 alumni make their mark in D.C.
Every month we’ll be touching base with past 40 Under 40 honorees to see what’s been happening in their professional and personal lives since winning the award. This month, we feature two outstanding professionals: HKS's Shannon Kraus and Roger Chang from Westlake Reed Leskosky.
| Jul 9, 2013
AISC releases Design Guide on Blast Resistant Structures
Design professionals now have a valuable new resource on blast resistant structures with AISC Design Guide No. 26, Design of Blast Resistant Structures.
High-rise Construction | Jul 9, 2013
5 innovations in high-rise building design
KONE's carbon-fiber hoisting technology and the Broad Group's prefab construction process are among the breakthroughs named 2013 Innovation Award winners by the Council on Tall Buildings and Urban Habitat.
| Jul 8, 2013
RSMeans cost comparisons: offices, daycare centers, convenience stores, fast food
Construction market analysts from RSMeans offer construction costs per square foot for offices, daycare centers, convenience stores, fast food.
| Jul 8, 2013
RSMeans cost comparisons: hotels, motels, and apartment buildings
Construction market analysts from RSMeans offer construction costs per square foot for hotels, motels, and apartment buildings.
| Jul 8, 2013
Learn from the world’s fastest animal: speed isn’t everything
Every schoolchild knows that the cheetah is the world’s fastest land animal—70 mph, no sweat. And, as we all know from National Geographic television documentaries, it is speed that makes Acinonyx jubatus such a fearsome hunter, right?
| Jul 3, 2013
Mid-year special: Top 13 stories for 2013 (so far)
Every six months, we like to take a look back at the stories that generated the most interest from our readers. Here's a roundup of the top 13 articles on BDCnetwork.com for the first six months of 2013.
| Jul 3, 2013
World's biggest freestanding building opens in China
Measuring a stout 100 meters high, 500 meters long, and 400 meters wide, the New Century Global Centre in the Tianfu New District of Chengdu, China, is officially the world's largest freestanding building.
| Jul 3, 2013
Mall of America will double in size after $2.5 billion expansion
The nation's largest indoor mall will undergo a $2.5 billion, 10-year expansion project that will add attractions like an NHL-sized skating rink and an indoor water park.