Steel in the News

StrucSoft Solutions, a developer and distributor of BIM software components, is offering a free webinar next Thursday for structural engineers looking to speed up design and verification of structural steel connections.

The webinar will provide an introduction to LIMCON, a Windows-based, graphical software tool that allows you to quickly and easily design and check steel connections in both SI metric and U.S. customary units, using the latest code from AISC 360-10 LRFD and ASD, BS 5950, AS 4100 and CAN/CSA-S16-09.

In this informational webinar you’ll learn how you can:

• Easily choose and plug in hundreds of standard steel connection types, including support for multiple-row moment and end plate connections

• Perform calculations in real time
• Check bolt and weld groups
• Check support for multiple codes
• View connections in realistic 3D
• Integrate detailing with DXF output

The webinar will begin at 2:30 p.m. EST.

Register here.

For more information about LIMCON, visit www.strucsoftsolutions.com/products/limc
on.

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 degrees Fahrenheit, 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.

Every year since 1999, AISC’s Lifetime and Special Achievement Awards have been given to outstanding industry professionals for their exceptional contributions to the advancement of the structural steel design and construction industry.

You can see what some this year’s winners had to say about their awards and achievements, favorite parts of their jobs and more via a new online video. You’ll also hear from a few of the industry experts who serve on the selection panel and learn about what they look for in award candidates.

This year, 10 leading professionals were honored for making a difference in the fabricated structural steel industry’s success and were presented with these distinguished AISC awards at the 2013 NASCC: The Steel Conference last month in St. Louis.

Photos of all of this year’s award winners and additional information about their achievements can be found in AISC’s press release.

The second quarter 2013 issue of Engineering Journal is now available online. Did you ever wonder how EJ got its name when it started 50 years ago? You can find out in this issue.

Papers in EJ Q2 include:

• Flange Bending in Single Curvature by Bo Dowswell
• Buckling Restrained Braced Frame with All-Bolted Gusset Connections by Patrick S. McManus, Addison MacMahon and Jay A. Puckett
• Uncertainty in Life-Cycle Assessment Induced by Life-Cycle Inventory Data: The Case of Structural Steel by Iordanis Zygomalas and Charalambos Baniotopoulos
• Current Steel Structures Research No. 33 by Reidar Bjorhovde

Article searches for the complete collection of EJ remain available at www.aisc.org/ej. Downloads of current and past articles in PDF format are free to AISC members and ePubs subscribers. Non-AISC members may subscribe to Engineering Journal at AISC’s website.

Is there a steel design topic that you would like to see addressed in more detail? EJ is always looking for your ideas. Email them to Keith Grubb, editor, at grubb@aisc.org.

The largest project in Ohio DOT history replaces an historic Cleveland crossing - the Interstate 90 Innerbelt Bridge - with a new delta girder bridge. The above photo shows a perspective of the “knuckle” portion of a delta girder at AISC member fabricator High Steel Structures’ shop. The new westbound portion of the bridge under construction will use 20,000 tons of structural steel in all. Photo: Courtesy of High Steel Structures

Interstate 90 provides major east-west access over the Cuyahoga River and through downtown Cleveland via what has become a functionally obsolete 1959 deck truss, thanks to a nearly 40% increase in vehicular traffic. Originally designed to carry a maximum of 100,000 vehicles daily, it now handles more than 138,000 cars a day.

When it came time to replace the historic structure, citizens were asked to vote on three steel alternatives: a cable arch scheme; a design with the deck supported on a series of slender, parallel beams spanning from pier to pier; and a delta girder scheme (the latter won). According to Dave Lastovka, project manager for the Ohio Department of Transportation (ODOT), the design is intended to complement Cleveland’s historic collection of steel river bridges while honoring steel’s role in the region’s economy.

At $640 million, which includes $79.4 million in American Recovery and Reinvestment Act funds, replacing the I-90 Innerbelt Bridge is the largest single infrastructure investment in ODOT history. And because the project is so large, ODOT broke it into two: a westbound bridge, which is under construction, and an eastbound bridge, scheduled to begin later this year.

The design-build team of Walsh Construction and HNTB Corporation (the latter also designed the original Innerbelt Bridge) was awarded the westbound bridge contract in September 2010.

The June issue of MSC (available June 1) will feature additional photos and detailed information about the Interstate 90 Innerbelt Bridge replacement project; stay tuned!