Accelerated Bridge Construction (ABC) has taken off in the United States in recent years. This is primarily due to two interrelated factors: The need to replace deteriorated bridges, and the need to minimize traffic congestion and maintain traffic flow during peak traffic hours.
The Utah Department of Transportation (UDOT) has completed 27 bridges using different ABC methods, and transitioned to ABC as standard practice in 2010. The ABC methods include everything from prefabricated elements, such as, decks to moving entire structures using self-propelled modular transporters (SPMTs).
UDOT continues to work with contractors and other industry partners, such as, Utelite Corporation to improve ABC methods and specifications, and to speed up bridge replacement.
The fastest UDOT replacement to date was the $4.5 million 3300 South Bridge, a pre-constructed one span bridge structure over I-215 East, which utilized structural lightweight concrete. On Sunday, August 24, 2008, the bridge was replaced in just 19 hours – 36 hours less than the 55-hour window allotted. The bridge was open for traffic the next day. Rukhsana Lindsey, Senior UDOT Research Bridge Engineer, valued the user (public) savings at an estimated $4,000,000.
The 80-ft-wide, 130-ft-long, 1.6-million pound bridge uses an expanded shale lightweight aggregate made by Coalville, Utah-based Utelite Corporation. “The structural lightweight concrete density was about 115 lb per cubic sq foot, compared to 150 lb per sq cubic foot for regular stone,” said Jim Deschenes, Assistant Vice President with Michael Baker Corp., whose Midvale, Utah office was the design engineer. “Most of the weight savings was in the lightweight concrete, along with optimized steel girders,” said Deschenes.
Based on UDOT ABC Bridge Consultant, Michael Culmo (CME Connecticut), evaluation of the 3300 South I-215 East Bridge, UDOT has expanded it’s ABC lightweight bridge program to include: I-80 2300 East Bridge, both I-80 Echo Bridges and the recent $97.5 million Layton Interchange on Interstate I-15. The Layton Interchange, completed in August 2010, utilizes the benefits of structural lightweight concrete to reduce overall project costs and to minimize cracking. This was the first multi-span bridge to use this technique in Utah (http://www.youtube.com/watch?v=054yOTuJ_XA).
Utah is making an important investment to restore and expand I-15 to support economic development and improve transportation in Utah County through the year 2030. Utelite expanded shale lightweight aggregates will continue to play a key role in the 27 additional Accelerated Bridge Construction projects planned along the Corridor Expansion Project, called I-CORE, in the near future.