Work Zone Mobility and Safety Program
Photo collage: temporary lane closure, road marking installation, cone with mounted warning light, and drum separated work zones.
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Best Practice

Main Guidebook > Find a Practice > Best Practice Categories > Construction/Maintenance Materials, Methods, Practices, and Specifications

BEST PRACTICE:

G1−6: Accelerated Bridge Construction

DESCRIPTION:

Accelerated bridge construction (ABC) involves using various methods during project, planning, design, contracting, and construction to significantly reduce the time to construct/re−construct a bridge, as compared to traditional cast−in−place methods, while maintaining quality. Methods include:
• Working with stakeholders to innovate during planning;
• Accelerating certain activities, such as right−of−way acquisition, utility relocation, or materials procurement, so that they occur before project advertisement;
• Using pre−fabricated elements, such as deck segments, that are built off−site and can be quickly put in place once on−site;
• Moving into place entire structures already built off−site using self−propelled modular transporters (SPMTs); and/or
• Using accelerated scheduling to reduce project delivery times.

ABC may involve using one of these methods on a project, or several of them in combination.

Utah Department of Transportation (UDOT) began using ABC elements in 1997 and has now employed ABC methods and elements in over 200 settings. In Utah, ABC is considered for inclusion on all projects involving structures. For its Riverdale Road over I−84 bridge in 2008, UDOT used ABC to reduce the construction impact to the area. The bridge was constructed in phases using almost all pre−fabricated elements, reducing road closures and detours by several months, which equated to a road user cost savings of over $2 million. On I−80 at Mountain Dell and Lambs Canyon near Salt Lake City, UDOT replaced 4 bridge superstructures in 37 hours over two weekends by building the bridges in the median adjacent to the existing structures over four months and transporting them into place using SPMTs. By coordinating with local media for construction updates, meeting with the local community throughout the construction process, and posting information in common areas for travelers, UDOT was able to mitigate construction impacts and meet safety and mobility needs. Using off−site construction and SPMTs, UDOT estimated that motorist delay was decreased by 180,000 hours, which equated to a savings of over $2.5 million.

Many other states are using ABC techniques to shorten their project delivery times, including Virginia and Florida. Virginia DOT replaced the George P. Coleman Bridge along Highway 17, near Yorktown, VA, in nine days by using a barge to float in the four−lane prefabricated replacement bridge (consisting of 2,540 feet of truss and swing spans). In 2006, Florida DOT was the first to use SPMTs in the United States to replace a bridge across an Interstate. The old Graves Avenue Bridge was moved from its current position across I−4 to the side of the road for demolition in 22 minutes. Then SPMTs were used to move the new spans from their fabrication site along I−4 to the bridge location, limiting the impact on motorists to only 2 weekend nights of detours/closures along the corridor.

REASON(S) FOR ADOPTING:

Building bridges over existing roads can create long term work zones, which can be disruptive to traffic and can pose safety concerns for drivers and construction workers. Accelerated bridge construction limits construction time over the existing road, often reducing this time from months to days, thus minimizing safety and mobility impacts.

PRIMARY BENEFIT(S):

Accelerated bridge construction reduces exposure to work zones, increasing work zone safety for drivers and construction workers. It limits user delays and minimizes traffic disruption during bridge construction. Because the bridges are constructed in a controlled environment, the quality is generally improved and the cure times are reduced. The construction cost for ABC can be more expensive than traditional construction methods (at least in the beginning as crews and owner−agencies are learning the methods and acquiring equipment), but can reduce total project costs due to lower project traffic control costs and lower fuel use and travel time for people driving (user costs), and create a positive public image for the DOT.

MOST APPLICABLE LOCATION(S)/PROJECT(S):

Bridges being built or reconstructed over existing highways.

STATE(S) WHERE USED:

Florida, Utah, Virginia

SOURCE/CONTACT(S):

Amy Scales, Florida DOT
Phone: (386) 943−5729
E−mail: amy.scales@dot.state.fl.us
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