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 | Jul 21, 2015
Architecture Billings Index at highest mark since 2007
This is the first month in 2015 that all regions are reporting positive business conditions, said AIA Chief Economist Kermit Baker.
BIM and Information Technology | Jul 20, 2015
New stylus brings digital sketching to the next level
Without buttons, users can change the weight of the stylus’ stroke.
Architects | Jul 20, 2015
New York design competition looks to shed the sidewalk shed
New York, which has nearly 200 total miles of sidewalk sheds, is seeking a concept that is practical but that also looks good.
Cultural Facilities | Jul 19, 2015
SET Architects wins design competition for Holocaust Memorial
The design for the memorial in Bologna, Italy, is dominated by two large metal monolithic structures that represent the oppressive wooden bunks in concentration camps in Germany during World War II.
Sports and Recreational Facilities | Jul 17, 2015
Japan scraps Zaha Hadid's Tokyo Olympic Stadium project
The rising price tag was one of the downfalls of the 70-meter-tall, 290,000-sm stadium. In 2014, the cost of the project was 163 billion yen, but that rose to 252 billion yen this year.
Cultural Facilities | Jul 16, 2015
Louisville group plans to build world's largest disco ball
The sphere would more than double the size of the current record holder.
Education Facilities | Jul 14, 2015
Chile selects architects for Subantarctic research center
Promoting ecological tourism is one of this facility’s goals
BIM and Information Technology | Jul 14, 2015
New city-modeling software quantifies the movement of urban dwellers
UNA for Rhino 3D helps determine the impact that urban design can have on where pedestrians go.
Industrial Facilities | Jul 14, 2015
Tesla may seek to double size of Gigafactory in Nevada
Tesla Motors purchased an additional 1,200 acres next to the Gigafactory and is looking to buy an additional 350 acres.
BIM and Information Technology | Jul 14, 2015
Nation’s first 'drone park' breaks ground in North Dakota
This is one of six testing sites around the country that are developing flight standards and evaluating the utility of drones for different tasks.