Steel in the News

Adding steel cross braces to stiffen tall concrete piers made isolation bearings an effective seismic solution for the retrofit of the Antioch Toll Bridge in Northern California. Photo: Y.P. Kim

If you’re a bridge in California, you’re going to need your outfit updated every so often to prevent any damage to your apparel. The Antioch Toll Bridge in Northern California recently received a seismic makeover and is one of the last two toll bridges to be retrofitted in the northern part of the state.

The seismic retrofit of the bridge consisted of replacing the existing bearings at all 39 piers and at the abutments with seismic isolation bearings. In order to make the isolation bearings work effectively, it was also necessary to install steel bracing in the tall piers to make the pier portal frames stiffer. The 1,850 tons of steel for the retrofit was fabricated and prime painted by AISC member Brooklyn Iron Works, Inc., Spokane, Wash.

The main structure is 8,650-ft long with 40 spans arching over San Joaquin River. The midsection of the bridge rises as high as 147 ft to allow for ship passage. The superstructure consists of two weathering steel plate girders that are continuous over the piers. The girders are in excellent condition, having formed the expected uniform protective outer coating with no degradation in structural capacity.

The Antioch Toll Bridge was constructed in 1978, so the lessons learned from the San Fernando Earthquake of 1971 were implemented in the original design. For this reason, the bridge was long considered to have sufficient earthquake resistant features and deemed safe. However, reevaluating the bridge based on on the latest seismic design criteria and an extensive geotechnical investigation, Caltrans concluded that the bridge needed to be retrofitted.

The seismic retrofit based on isolating the superstructure was a simple but effective solution. Implementing this scheme by adding steel cross braces to the concrete pier frames was an ideal match. Shop fabricated segments of the steel braces were field assembled with bolted connections and the bracing was easily integrated to the existing concrete frame by connecting the two different elements through a cast-in-place concrete pedestal.

Due to steel’s light weight, the additional weight of the bracing could be accommodated within the capacity of the existing foundation. Not requiring a foundation retrofit meant big savings in the construction cost and also minimized the disturbance to the sensitive environment.

You can read more about the seismic retrofit of the Antioch Toll Bridge in the February issue of MSC, available now.

The Huey P. Long Bridge, which crosses the Mississippi River in New Orleans, has been named a National Historic Civil Engineering Landmark by the American Society of Civil Engineers (ASCE). The designation makes this steel structure one of fewer than 250 ASCE landmarks in the world including the Eiffel Tower, the Panama Canal and the U.S. Capitol Building. You can find a full list of appointed landmarks on the ASCE website at http://bit.ly/zzA6LK, all illustrating the creativity and innovative spirit of civil engineers.

The Huey P. Long Bridge is now in the final phase of a $1.2 billion widening project. When completed in 2013, the expanded bridge will have an additional travel lane and inside and outside shoulders to each side of the bridge. The total width will more than double the current driving surface to 43 ft wide. The project also includes construction of new elevated bridge approaches and ramps, as well as new intersections with traffic signals at Bridge City Avenue and Jefferson Highway.

(Click on the thumbnail photo to view one of our previous news posts with links to more photos and information about the Huey P. Long Bridge widening project.)

“The ASCE is nationally recognizing what civil engineers in New Orleans have always known,” said New Orleans ASCE President Malay Ghose Hajra, Ph.D., P.E. “The design and construction of the Huey P. Long Bridge was a groundbreaking achievement for our country and the world. We are extremely proud to have played a role in getting this historic recognition for this historic bridge.”

Design of the bridge began in 1926 and at that time, engineers had only limited tools for measuring and calculating, unlike today. They designed the bridge for safety and strength to deal with difficult, sandy soil conditions. It was the first Mississippi River Bridge in New Orleans when it opened in 1935 and the longest railroad bridge in the world for about 15 years. Prior to the bridge being built, railroad cars had to be ferried across the river.

Louisiana Governor Huey P. Long was responsible for the addition of driving lanes for automobiles during construction of the bridge, which began in 1932. He provided the New Orleans Public Belt Railroad with $7 million to build the two narrow lanes in each direction. The lanes were adequate for the types of vehicles and limited traffic of the time, but are not wide enough by current standards.

"Huey Long prided himself on forward-thinking and well-designed infrastructure projects,” said Russell Long Mosely, the great-grandson of Huey P. Long. “Although completed in 1935, the Huey P. Long Bridge in New Orleans remains structurally sound. It serves millions of motorists each year and remains one of the longest and highest railroad bridges in the United States. The family of Huey Long is delighted that this bridge has been designated as a Civil Engineering Landmark."

What do you get when you cross a kaleidoscope and a skyscraper? A building with independently rotating floors whose appearance changes continuously. That’s the brainchild of architect David Fisher, whose Dynamic Architecture Group has worked out a plan to develop such a structure (an 80-story version) using pre-fabricated elements shipped to the site for assembly. It would, in essence, be a factory produced skyscraper. And although it’s pricey, just the fact that we now have the technology to do this is pretty amazing.

For a great explanation and appreciation of this thought-provoking concept, as well as additional images, read the recent post by Tami Hausman at http://bit.ly/zXDAso.

With transportation infrastructure spending a key issue in Congress, MetalMiner (a sourcing and trading intelligence website for global metals markets) recently interviewed Roger Ferch, NSBA executive director and Jennifer Diggins, director of public affairs for Nucor Corp., to get an update on the Buy America legislation and its effect on U.S. manufacturers.

In the interview Ferch discusses how contractors on the San Francisco-Oakland Bay Bridge project skirted Buy America provisions to procure structural steel and labor from China, potentially costing hundreds or even thousands of jobs for U.S. steel industry workers. NSBA has been active in voicing its objections to purchasing foreign steel and off-shore fabrication for U.S. domestic projects such as the Bay Bridge project.

Watch Ferch’s video interview segment on the MetalMiner website at http://bit.ly/wq9YhD.

In Diggins’ interview she clarifies common misconceptions of the Buy America legislation, and offers her perspective on how prospective U.S. presidential candidates would serve the country’s manufacturing industry and job creation.

Watch Diggins’ video interview segment on the MetalMiner website at http://bit.ly/yvjHz8.

NSBA and AISC encourage the steel community to take action on Buy America issues and contact their local representatives through the NSBA/AISC Legislative Action page at www.aisc.org/action.

If you haven’t had the time to take advantage of the following AISC opportunities, or weren’t aware they were available to you -- don’t panic! The deadlines to participate have been extended:

• Recently work on an innovative steel building project? Entries for AISC’s 2012 IDEAS2 Awards program are now due on Friday, February 3, at 5 p.m. Central Time. There is no fee to enter for AISC members. More information about the program and how to enter can be found in our previous news post.

• Brewing any ideas that can help advance steel building design and construction? AISC is seeking proposals for research projects aimed to improve the safety and economy of steel building design and construction, including the development of innovative structural steel systems. Proposals will be awarded in 2012 and the research will be conducted in 2012 and 2013. The deadline for notice of intent to submit a proposal has been extended to 5 p.m. Central Time on Friday, February 10. The complete proposals are still due March 5. You can find additional information and links to enter in our previous news post.

P.S. -- Speaking of deadlines, remember that you can still save money on your 2012 NASCC: The Steel Conference registration by signing up early. Register this week and save $90 or more. Details are at www.aisc.org/nascc.