- Briefing Room
U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
|Accelerating Infrastructure Innovations|
Publication Number: FHWA-HRT-08-011
Date: March 2008
For the Utah Department of Transportation (UDOT), the use of accelerated bridge construction (ABC) technologies and techniques is not just a one-time event but a successful business practice that is rapidly becoming the norm, not the exception. Since first using prefabricated bridge systems and ABC in 2002, UDOT has completed 10 projects that incorporated different ABC elements and technologies, ranging from full-depth precast concrete deck panels and bent caps to total superstructure systems and the use of self-propelled modular transporters (SPMTs) to replace bridges in a matter of hours. "The goal of all these innovations is the same-to find a way to replace or fabricate a bridge in an extremely short time," says Carmen Swanwick of HDR Engineering, UDOT's consultant for ABC.
|The Utah Department of Transportation used an accelerated construction strategy to replace the 4500 South bridge in Salt Lake City in a single weekend.|
As the nature of highway construction has evolved from building the Interstate and highway system in areas where infrastructure did not exist to rehabilitating roads and bridges in highly congested areas, conventional construction techniques have reached their limit for decreasing user delays. "Today's projects have enormous impacts, especially to the traveling public. As user costs mount, the pressures to decrease project durations increase," says Jim McMinimee, UDOT Director of Project Development. UDOT has found that the benefits of using ABC include not only a shortened schedule but increased safety for both road users and construction workers and increased quality. With less time spent in work zones, the risk of crashes affecting road users and workers decreases. And the use of prefabricated elements and systems that can be constructed offsite allows for better cure times, more durable mix designs, and the advantages of a controlled manufacturing environment.
While UDOT encountered increased costs for its initial projects that used prefabricated bridge systems and other ABC techniques, it was willing to absorb more upfront costs because there was the possibility of tremendous long-term economic benefit. Costs have since decreased for subsequent projects. The economic benefit has also been realized by the accompanying reduction in user costs. For example, using an ABC strategy to replace the 4500 South bridge over the I-215 East Loop in Salt Lake City in October 2007 cut road closures and detours from 6 months to a single weekend and saved $4 million in road user costs (see December 2007 Focus). The superstructure of the new concrete and steel bridge was constructed offsite over a period of 4 months, while the abutments for the new bridge were constructed underneath the existing bridge without impacting traffic. SPMTs were used to both remove the old bridge and to lift the new bridge into place. While using SPMTs cost an additional $800,000, for UDOT this increase was offset by the substantial reduction in user costs.
|"Today's projects have enormous impacts, especially to the traveling public. As user costs mount, the pressures to decrease project durations increase."|
UDOT's shift to ABC has required the confidence and support of its senior leaders. While institutional hurdles had to be overcome, careful selection of projects and techniques to implement has fostered support within the agency. The successful 4500 South project, for example, has been important in gaining support for using innovative strategies. "UDOT's Bridge Division has developed into champions of ABC, is working to become experts in its applications, and has adopted the idea that all projects are considered for implementing ABC methods first and lapse to traditional methods only if the project cannot benefit from decreased schedules," says McMinimee. ABC projects planned for this year include using SPMTs to replace 13 bridges on I-80.
|Utah used self-propelled modular transporters to remove the old 4500 South bridge.|
Another key to achieving success with ABC has been UDOT's collaboration with contractors and the business community. UDOT conducted several scanning tours to visit and learn about innovative ABC projects in New York, New Jersey, Louisiana, and Florida. The scanning tours included representatives from both UDOT and industry. "These opportunities allowed business representatives to see, touch, and feel projects and, more importantly, to talk to business people who had already implemented ABC. These were people who could provide information and lessons learned," says Swanwick. UDOT also met with the Utah Associated General Contractors to gather input and gain support for the ABC program. "ABC is a partnership among the owner, design industry, and construction industry. To transition from traditional methods of contracting requires the buy-in and support of all parties," says McMinimee.
UDOT's additional lessons learned and best practices include the importance of using innovative contracting methods in conjunction with ABC. Such innovative methods as design-build contracting and construction management general contractor (CMGC) contracting have helped to advance ABC implementation. Another tool that UDOT is using is a Framework for Prefabricated Bridge Elements and Systems Decision-Making (Pub. No. FHWA-IF-06-30) developed by FHWA that helps managers plan projects at the concept level. UDOT is also developing standard drawings and specifications for the use of full-depth precast concrete bridge decks and SPMTs. Future standards are planned for additional bridge superstructure and substructure elements. "Building contractor expertise and the industry infrastructure to support the use of ABC is a priority for UDOT," says McMinimee.
To learn more about UDOT's ABC program, contact Jim McMinimee at UDOT, 801-965-4022 (email: firstname.lastname@example.org). For more information on ABC, visit www.fhwa.dot.gov/bridge/accelerated/index.cfm, or contact Vasant Mistry at FHWA, 202-366-4599 (email: email@example.com). The Framework for Prefabricated Bridge Elements and Systems Decision-Making is available online at www.fhwa.dot.gov/bridge/prefab/framework.cfm.