In this fast paced construction world, everyone is looking for ways to get the job done faster. When it comes to repairing and constructing our infrastructure, especially bridges, the government understands that time is money and getting the job done in a timely fashion is essential. So much so, that incentives may even be offered for early completion. The Federal Highway Administration promotes a technique called accelerated construction for safely decreasing the amount of time a construction project takes and its impact on the surrounding environment using several available methods and technologies to get the job done faster and safer.
Accelerated construction is becoming increasingly popular for building and remodeling of bridges. Accelerated Bridge Construction (ABC) is not new. ABC involves using techniques and technologies in planning, design, contracting and construction of bridges to help limit safety and mobility impacts during a project. Pre-fabricated components and off-site construction are two primary methods for ABC, according to an FHWA Accelerated Bridge Construction fact sheet. In this method, bridges are constructed near but off the construction site and then moved into place to reduce impacts on traffic flow. Off-site built components can then be moved into place using self-propelled modular transporters (SPMT).
According to the FHWA fact sheet: "Because exposure to work zones is reduced, safety for the traveling public and construction workers is improved. By limiting the time spent at the site reconstructing the bridge, construction impacts to the surrounding environment are reduced. Because ABC often involves building part or all of a bridge in a controlled environment away from live traffic, the end product is generally of higher quality and productivity is often greater as workers can focus on their work with less distractions from traffic."
One recent history-making ABC project involved the Sam White Bridge and Interstate 15 in Utah. The 354-foot, two-span bridge was constructed on the side of the freeway and then moved with SPMTs. The move was done in one night and the freeway was able to open three hours earlier than scheduled.
Utah has completed 23 ABC projects using the SPMT method while seven other states (Florida, Illinois, Louisiana, Massachusetts, New York, Rhode Island, and Washington) have moved 13 bridges with the SPMT method.
For more information on ABC methods and how the FHWA is promoting the process, check out the FHWA's Accelerated Bridge Construction website.
[caption id="attachment_3361" align="alignnone" width="300" caption="The Sam White bridge was built on the east of the freeway in a "bridge farm" using ABC from July 2010 to March 2011 and then moved into place using two sets of self-propelled modular transporters."][/caption]
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