Steel in the News

During this initial stage of shock, we as representatives of the bridge industry are thankful there were no fatalities and pray for the speedy recovery of the survivors, as well as applaud the excellent rescue efforts.

At this time, the Washington State Department of Transportation is starting their investigation. Premature speculation about potential causes is neither appropriate nor productive. Rather, this is a time for careful, comprehensive engineering analysis and for rapid response to the human and transportation impacts of this disaster. NSBA and the steel industry stand ready to aid in any way we can and will share more information as it becomes available to us.

Whatever the eventual findings, this unfortunate event serves to graphically illustrate the decaying state of our country’s infrastructure – not only bridges, but also roadways and railroads across the country. NSBA is dedicated to reversing this deterioration by urging Congress to invest in infrastructure improvements that will make our nation’s transportation systems more efficient, robust and reliable.

Bill McEleney, Director, National Steel Bridge Alliance

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!

In less than two weeks, nearly 50 university teams will converge at the University of Washington in Seattle to compete in the 2013 National Student Steel Bridge Competition finals, which take place May 31-June 1.

The competition challenges student teams with building their own designed and fabricated steel bridges, one-tenth the size of a full-scale bridge, under the pressure of the clock. Bridge rankings are based on a variety of factors, including: display, construction speed, stiffness, lightness, construction economy and structural efficiency.

The 49 student engineering teams that have qualified for the national competition were the top finishers at 18 regional competitions that took place across North America between January and April and included a total of 210 teams. (Click on the left image to view the list of qualifying teams.)

For more information about the competition, visit www.aisc.org/steelbridge or www.nssbc.info.

Chicago’s bascule bridges are some of the city’s most iconic structures but many are in trouble, according to a recent Chicago Sun-Times article. These bridges have made Landmark Illinois’ “Ten Most Endangered Historic Places” for 2013.

While many of the moveable steel bridges are still in operation, others are no longer operable and are due to be replaced in upcoming years with new wider, fixed bridges, according to Landmark.

And despite the city’s $41 million Wells Street Bridge reconstruction project currently underway, other bascules, while not planned for replacement, are deteriorating due to a lack of capital repair funds.

The article says that the city’s Department of Transportation is preparing a bridge preservation plan in hopes that parts of those bridges in need of replacement could be salvaged.

AISC is offering the opportunity to dive into the topic of fatigue of welded connections with a two-part live webinar on May 23 and May 30 titled “Fatigue of Welded Connections - A Primer.”

Part 1, on May 23, will examine the basic concepts behind fatigue including the definition, application and causation, as well as welded connections and variables affecting fatigue. It will also review the aspects of the design model including fatigue testing, categories of connection details and predictive model.

Part 2, on May 30, considers weld geometries in detail with a practical focus on how to increase the fatigue resistance of welded connections. Fatigue enhancement methods will be presented and the role of material toughness on fatigue life will be discussed, along with case studies.

Both parts of the webinar are 1.5 hours long and will use AISC 360 Appendix 3. On both days they will begin at the following times, relative to time zone:

10:30 a.m. PDT
11:30 a.m. MDT
12:30 p.m. CDT
1:30 p.m. EDT

The cost of the two-part webinar series is $325 for AISC members, $500 for non-members and $270 for students and educators. (Fees are based on a per-site connection basis. Purchase one site connection and any number of members in your company or organization may view the webinar at that site connection. All attendees are eligible to receive CEUs/PDHs.)

Registrants will receive access to a PDF file of the presentation slides prior to the webinar, CEU/PDH certificates for all attendees upon completion of the live webinar (up to 0.30/3.0 CEUs/PDHs) and complete instructions for accessing the live webinar.

For more information and to register, go to www.aisc.org/webinars.

The final sections of the 408-ft steel spire for One World Trade Center were lifted to the top of the building earlier this month and installed this past Friday. The skyscraper now stands at a symbolic 1,776 ft high, making it the tallest building in the Western Hemisphere and the third tallest in the world.

Eighteen barrel-shaped sections of steel make up the spire, which weighs nearly 760 tons and will function as world-class broadcast antenna.

You can view videos and photos of welders installing the spire at WABC-TV’s website.

The steel for the building topped out last August when the last of the spandrel beams were installed between the parapet columns. The 104-story high-rise will open in 2014 on the northwest corner of NYC’s World Trade Center site — overlooking the Statue of Liberty and Ellis Island — with 3 million sq. ft of office space.

More information on WTC’s construction progress can be found at www.panynj.gov/wtcprogress.