THE CONCRETE BRIDGE MAGAZINE

SUMMER 2012

ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

Issue link: http://www.aspiremagazinebyengineers.com/i/297030

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A C C E L E R AT E D B R I D G E C O N S T R U C T I O N South Maple Street Bridge To complete the first, totally precast concrete bridge in the town of Enfield, Conn., town officials used ABC concepts to reduce user costs. As a result, the structure was erected in just 17 days. The South Maple Street Bridge, which spans the Scantic River, was assembled from 71 precast concrete components. The concept used precast concrete adjacent box beams, with a continuous-length lip extending in front of the abutment panels to hide the horizontal joint. Additional components comprised footing blocks with threaded jacks to level them to grade after setting, 10 abutment walls, 12 wingwall pieces cast in decorative patterns, 4 cheek walls, and 12 pavement approach slabs. The contractor cast an unreinforced "mud slab" at the abutment sites and set the footing blocks on them. The abutment walls and wingwalls then were set over the reinforcing bars and the dowel bar splice sleeves were grouted. The precast concrete abutment bridge seat was set onto the projecting reinforcing bars from the abutment walls, allowing the abutment pieces to act as one unit. Then the box beams were set on elastomeric bearing pads on the precast bridge seat. Following erection of the box beams, the precast concrete cheek walls and precast concrete approach slabs were erected. Mitchell Gulch Bridge Precast concrete abutments and pier caps offer a strong option for accelerated construction schedules. State Highway 86 Bridge over Mitchell Gulch in Colorado is another example of those benefits. The use of precast concrete abutments allowed the bridge to be constructed over the weekend and open only 46 hours after closure. The original timber bridge was replaced with a 40-ft-long, 43-ft-wide, single-span precast concrete slab superstructure and precast, reinforced concrete abutments. The precast concrete abutments and wingwalls with embedded steel plates were erected by crane and welded to the steel H-piles and to each other, finishing in less than two days. These projects present several innovative ways precast concrete components are being used to accelerate bridge construction while meeting a variety of needs for economy, aesthetics, and durability. By using easily designed techniques, the projects achieve their goals while also ensuring bridges are brought into service quickly. __________ This is the first in a series of articles examining different approaches to Accelerated Bridge Construction and examples featuring those techniques. Details of these projects can be found in the issue archive at www.aspirebridge.org. They originally appeared in the Spring 2007 issue (Mill Street Bridge and Mitchell Gulch Bridge), Fall 2009 issue (Route 70 Bridge), and Summer 2011 issue (South Maple Street Bridge). For additional photographs or information on this or other projects, visit www.aspirebridge.org and open Current Issue. The State Highway 86 Bridge over Mitchell Gulch in Colorado. ASPIRE , Summer 2012 | 27 ASPIREBook_Sum12_R02.indb 27 6/29/12 12:39 PM

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