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GRIDLINE, Issue #10, February 2014

We Are Giving Away An Apple iPad - Enter to Win Below

 

We hope everyone closed 2013 with a safe and happy holiday season!  To start off the new year on the right foot, the BGFMA is giving away a brand new Apple iPad to a lucky survey participant!  We will be conducting a short online survey to see how many of you visit our website, read our newsletters, and know the very basics about grid deck systems! If you are signed up on our distribution list, then you are automatically registered to participate. The survey will be emailed out in February to everyone on our email distribution list, and all you need to do is correctly answer a few short survey questions that will only take a few minutes of your time. The survey must be completed by the end of February, and the lucky winner of the iPad will be announced when our next technical bulletin, Tech-Line #10, is sent out in the March /April timeframe. The winner will be drawn randomly and given the option to choose between several different iPad models.


If you received this newsletter from a friend or colleague and are not registered but would like to be, just visit our website www.bgfma/contact.htm no later than February 14th and submit a contact form requesting to be added. Good luck to those who participate and please do not hesitate to contact the BGFMA if you have any questions about grid deck systems or our survey!

 

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Two Grid Deck Projects Showcased in Roads & Bridges

 

In the last BGFMA Gridline newsletter we highlighted the use of a grid reinforced concrete deck for redecking of the Walt Whitman Bridge, which was selected for several reasons including speed of construction, weight savings and durability. That newsletter also included an article which explained how a modular and lightweight grid deck was used to overcome several staging hurdles on Scott Road Bridge No. 6 over Montour Run, a small county bridge in Allegheny County, PA. We are pleased to have shared both of these case studies with readers of Roads & Bridges (R&B) magazine.

An electronic case study about the Walt Whitman Bridge redecking project was emailed out to nearly 40,000 R&B subscribers in late October 2013. Click here to read about this project. Click here to read about our case study highlighting the use of a grid deck on the unique Allegheny County bridge that was completely replaced over Thanksgiving weekend.

 

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Pulaski Skyway - Contract Three Redecking Kicks Off After Super Bowl XLVIII

 

Although significant construction is already underway to rehabilitate the section of U.S. Route 1 and 9 in New Jersey between Newark and Jersey City, a.k.a. Pulaski Skyway, motorists will not see significant impacts from the traffic detours used during Skyway redecking until late February or March. The New Jersey Department of Transportation (NJDOT) did a great job of coordinating this project with other regional transportation construction projects, as well as the Super Bowl. The Skyway's northbound travel lanes will be shut down now that the Super Bowl festivities have concluded. However, even without the added traffic caused by Super Bowl travelers, the Skyway traffic volume approaches 70,000 vehicles per day. Considering the large traffic volume and the fact that the structure is only four lanes wide, minimizing construction inconveniences to the traveling public was a major engineering challenge. Like all high profile projects, several design and construction concepts were evaluated to determine the best solution to minimize not only costs, but social, economic, and environmental impacts as well, while extending the life of the structure. In this case, the ultimate goal is to extend the service life of the Skyway by 75 years!

The NJDOT decided to use a combination of precast Exodermic® bridge deck panels and conventional precast deck panels to accelerate construction and reduce dead load on the 80-year-old structure. This preferred rehabilitation alternative will require full-time, half-width closures during the execution of Contracts 3 and 4 that will only allow southbound traffic to pass. By using the precast Exodermic® deck, the closure time is significantly reduced. In fact, redecking the entire three and a half-mile-long structure is anticipated to take only two years, when more conventional construction methods would have extended traffic closures by several additional years. Between Contracts 3 and 4, nearly 260,000 square feet of new precast Exodermic® deck panels will be installed over the two-year period.
 
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Grid Facts

 

The BGFMA is often asked about overhang capacity of grid deck systems. All grid reinforced concrete decks are orthotropic in nature, which means they have distinct strong and weak directions that are orthogonal to each other. The strong direction of the deck always runs normal to the deck support elements (floor beams, stringers, etc.) and consequently lies parallel or perpendicular to the direction of traffic.



Grid reinforced concrete decks designed with main bars perpendicular to traffic generally have enough capacity to resist the loads imposed on the deck overhang without need for additional reinforcement; however, increasing the strength of the deck if required, is easily accomplished. If a barrier is supported by a grid reinforced concrete deck designed with main bars parallel to traffic, then there is no overhang, but the capacity of the deck needs to be checked for the barrier impact load.

If you would like to read more about overhang design for grid systems, please read BGFMA Techline #4, which is available on our website. Also, please contact the BGFMA for assistance in evaluating the overhang for a specific structure.

 

Need More Information?

                       

If you would like to receive more information about the features and benefits of grid deck systems, please contact us at 1-877-257-5499 or bgfma@bgfma.org. We are also available to make presentations at your office and can offer continuing education credits for professional engineers as a registered provider in New York and Florida.

 

Please visit BGFMA members at our exhibit booth during the upcoming 2014 conferences:

 

  • NASCC Steel Conference (NSBA) in Toronto, Canada - March 26-28, 2014
  • International Bridge Conference in Pittsburgh, PA - June 8-12, 2014
  • Heavy Movable Structures Symposium in New Orleans, LA - Sept. 15-18, 2014

1.877.257.5499

WWW.BGFMA.ORG