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
| Mar 9, 2012
2012 Giants 300 survey due Friday, April 13
See how your firm ranks among the AEC industry leaders.
| Mar 7, 2012
Firestone iPad app offers touch technology
Free app provides a preview of Firestone’s Roots to Rooftop Building Envelope Solution with an overview of all the products from ground and stormwater management solutions, to complete wall panel and commercial roofing system applications.
| Mar 7, 2012
LEO A DALY opens new office in Riyadh, Saudi Arabia
Jay N. Kline, Regional Manager – Saudi Arabia, to lead new office.
| Mar 7, 2012
Turner appointed Batson-Cook CFO and treasurer
Cecil G. Hood to continue in advisory role.
| Mar 7, 2012
Thornton Tomasetti names Dowdall VP of Kansas City office
Dowdall will be responsible for supporting the Property Loss Consulting, Building Performance and Building Sustainability practices nationally.
| Mar 7, 2012
LEO A DALY selected to design Minnesota Fallen Firefighters Memorial
The bronze, figurative sculpture of a firefighter rescuing a child, which is currently on display at the Minneapolis/St. Paul International Airport, is lit by natural light through a circular void in the monolith.
| Mar 7, 2012
Houlihan Lokey adds Steffen to Industrials Group
Steffen bolsters group with experience in the building materials and rorest product sectors.
| Mar 6, 2012
Country’s first Green House home for veterans completed
Residences at VA Danville to provide community-centered housing for military veterans.
| Mar 6, 2012
EwingCole completes first design-build project for the USMA
The second phase of the project, which includes the academic buildings and the lacrosse and football fields, was completed in January 2012.