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
Architects | May 16, 2017
Architecture that helps children fall in love with the environment
The coming decades present a major ecological challenge... so let’s encourage the next generation to do something about it!
AEC Tech | May 11, 2017
Accelerate Live!: Social media reactions from BD+C's AEC innovation conference
BD+C's inaugural Accelerate Live! innovation conference took place May 11, in Chicago.
Multifamily Housing | May 10, 2017
Triple Treat: Developer transforms mid-rise into unique live-work lofts
Novus Residences’ revolutionary e-lofts concept offers tenants a tempting trio of options—‘live,’ ‘live-work,’ or ‘work’—all on the same floor.
Architects | May 9, 2017
Spiezle Architectural Group looks to the future
Now in its seventh decade, the firm expands its portfolio and moves into a larger HQs.
Architects | May 9, 2017
Movers + Shapers: The social connector
Studio Gang gains fans with buildings that unite people and embrace the outside world.
Architects | May 5, 2017
An acquisition extends Eppstein Uhen Architects’ national footprint
Has architects in 35 states after acquiring Burkettdesign in Denver.
Great Solutions | May 5, 2017
No nails necessary: Framing system comes together with steel zip ties and screws
Clemson University’s School of Architecture develops a patent-pending construction method that is gaining attention for its potential use in rapid, low-tech sustainable housing.
Multifamily Housing | May 3, 2017
Silicon Valley’s high-tech oasis
An award-winning rental complex takes its design cues from its historic location in Silicon Valley.
Architects | May 3, 2017
Avoiding trouble in paradise: Tips on building successfully in the Caribbean
The island setting itself is at the root of several of these disruptive assumptions.
Multifamily Housing | May 2, 2017
Multifamily housing: 7 exciting, inspiring innovations [AIA Course]
This AIA CES course features seven novel approaches developers and Building Teams are taking to respond to competitive pressures and build more quickly and with more attractive offerings.