Category Archives: Primary

Roads & Bridges, I-895 over Patapsco River Flats in Maryland gets ultra-light bridge deck

A partially filled concrete grid bridge deck was selected as a major component of the solution for the lightweight superstructure replacement on I-895 over Patapsco River Flats for the Maryland Transportation Authority (MDTA).

Due to the limited load capacity of the substructure and the desire to maintain an HS-20 design live load, Rummel, Klepper & Kahl, LLP specified a deck weight not to exceed 50 pounds per square foot utilizing 4500 psi, 100 pcf all lightweight concrete while still providing a 2” integral concrete overfill.

Although accelerated bridge construction (ABC) was not a requirement for this project, grid reinforced concrete decks have long been utilized by toll agencies to accelerate the speed of construction.  McLean Contracting Company is expected to wrap up construction in 2019.

The entire article can be found on the Roads & Bridges website by clicking here.

Route 37 EB Mathis Bridge – NJ’s Largest Precast Exodermic® Deck Replacement Project

Route 37 EB Mathis Bridge – NJ’s Largest Precast Exodermic® Deck Replacement Project was the subject of a recently featured webinar hosted by the ABC-UTC at FIU.  Click on the link to view the video recording of the presentation, a PDF version of the presentation and the Q and A.

Route 37 EB Mathis Bridge – NJ’s Largest Precast Exodermic Deck Replacement Project

 

TECH-LINE #18 – LRFR Design Load Rating of Grid Reinforced Concrete and Exodermic® Decks

Load rating is the determination of the safe live load carrying capacity of a highway structure. It is usually expressed as a Rating Factor (RF) or in terms of tonnage for a particular vehicle. Rating frequency may vary by owner but is usually performed in the design stage, initial inventory inspection, when there is a change of live loading or dead load on the structure, or if there is a physical change in any structural member of the bridge. The Manual for Bridge Evaluation, Third Edition, 2018 (MBE) implies that decks should be rated as a main load carrying component of the superstructure. Some owners may overlook this requirement for conventional reinforced concrete decks but require rating of grid reinforced concrete and Exodermic® decks for new construction.

Click here to view this latest technical bulletin (and all previous) and read how the BGFMA V3.1 design program can be used to supplement the MBE and AASHTO LRFD Design Specifications to load rate a deck (including an example).

BGFMA Gridline #18

View Gridline Newsletter #18 on the BGFMA website by clicking the link below and opening the newsletter http://bgfma.org/news.htm

Featured articles:

“Meet Timothy Pace, P.E.” continues the introduction of BGFMA Certified Fabricator members whose many years of experience can be valuable to provide sound advice during plan preparation, fabrication, and installation.

One of the more frequent questions asked of the BGFMA is to provide an approximate cost for a project.  The BGFMA took a closer look at the winning bids of three projects and summarized the deck costs in “Engineer’s Estimate for Grid Reinforced Concrete and Exodermic Bridge Decks.”  The projects include features of ABC construction, lightweight bridge deck applications, and precast concrete bridge deck panels to name a few.

The BGFMA recently donated Exodermic panels, rebar and form pans to Purdue University’s S-BRITE Center to be installed on a pony truss taken out of service.  The addition will enhance the gallery that serves to educate students, inspectors and professional engineers.

TECH-LINE #17 – Computation of Composite Section Properties

TECH-LINE #17 is now available online!  In this issue, the BGFMA provides equations to determine the neutral axis for grid reinforced concrete and Exodermic bridge decks using the transformed area method assuming the section is cracked.  Once determined, the moment of inertia and section moduli for selected locations can be calculated. To view the latest TECH-LINE and/or past bulletins & reports visit http://bgfma.org/bulreports.htm

Roads & Bridges, Special Deck Makes History on Liberty Bridge in Pennsylvania

Over 170,000 square feet of deck surface was replaced in an accelerated bridge construction (ABC construction) project highlighting Pennsylvania’s first use of an Exodermic deck.  Modular steel bridge deck panels were installed by both cast-in-place and precast methods.

Designers at HDR in Pittsburgh took advantage of the lightweight features of the Exodermic deck instrumental to remove the bridge from the states structurally deficient list.

“We selected Exodermic deck panel construction for this project due to its high strength to weight ratio and suitability for modular precast construction.  Accelerated construction using precast units on the north end of the bridge prevented significant weekday traffic impacts,” states Nick Burdette, P.E., of HDR.

The entire article can be found on the Roads & Bridges website by clicking here.

BGFMA Gridline #17

View Gridline Newsletter #17 on the BGFMA website by clicking the link below and opening the newsletter http://bgfma.org/news.htm

Featured articles:

“Meet Darko Jurkovic, P.E.” continues the introduction of BGFMA Certified Fabricator members whose many years of experience can be valuable to provide sound advice during plan preparation, fabrication, and installation.

“Getting into the Swing of It,” showcases the use of a lightweight Exodermic deck on the new Gasparilla Island Swing Bridge specified for its structural efficiency.

The results of the 2017 ASCE/AISC National Student Steel Bridge Competition are summarized.

“Grid Facts” presents in-service grid reinforced concrete decks that that have surpassed the current 75 year design life will most likely reach the 100 year bridge service life ultimate goal.

BGFMA Gridline #16

View Gridline Newsletter #16 on the BGFMA website by clicking the link below and opening the newsletter http://bgfma.org/news.htm

Featured articles:

“Meet Mike Riley” continues the introduction of BGFMA Certified Fabricator members whose many years of experience can be valuable to provide sound advice during plan preparation, fabrication, and installation.

“Georgia DOT Applies ABC Techniques over the Etowah River,” highlights the use of modular precast grid deck panels in accelerated bridge construction.  Using bare grid panels supplied by BGFMA Certified Fabricator Bailey Bridges, Contractor LC Whitford precast panels at their own facility in Alpharetta, GA and replaced both parallel spans each in a two week closure.

“South Park Bascule Bridge Replacement in King County, Washington Garners Awards,” showcases the use of a lightweight grid reinforced concrete bridge deck application on another movable span.  This replacement bascule structure was design-challenged to meet unprecedented seismic performance requirements for a movable bridge.

“Grid Facts” discusses the importance of 3/8″ maximum aggregate for all grid decks.