By Ashwat Anandanarayanan
Accelerated bridge construction (ABC) techniques are transforming the replacement and construction of bridges across the country, and commuters are benefiting from shorter construction schedules. The central component of accelerated bridge construction is the use of prefabrication technologies which allow the production of bridge components off-site. The parts are then shipped to an assembly site or loaded into place using large trailers called self-propelled modular transporters (SPMTs). Other ABC methods include efficient project planning, early stakeholder interaction, and the completion of certain essential tasks before project advertisement.
ABC technologies have significant benefits, the most notable being a reduction in project delivery time. ABC minimizes traffic disruption and reduces motorist exposure to work zones, improving safety for both the traveling public and construction workers. Bridges built off-site are likely to be of a higher quality due to their production in a controlled environment. Construction impacts to the surrounding environment are also reduced by limiting the time spent at the building site. Significant cost savings are achieved using ABC techniques.
Several states have embraced the use of ABC technology, with the most prominent being Massachusetts, which replaced 14 bridges on the I-93 over just 10 weekends. In New York, NYDOT used pre-fabricated components to replace the Belt Parkway Bridge in Brooklyn in 14 months, which was a significant reduction from the three to four years estimated using conventional methods. Other states using ABC techniques include Florida, Utah, Virginia, and Washington DC. Even the Golden Gate Bridge in San Francisco is receiving 78 prefabricated segments as part of a seismic retrofit. Read a New York Times article about the accelerated replacement of River Street Bridge in Boston here.
Ash Anandanarayanan is a graduate student in transportation engineering at UW-Madison and an intern at SSTI. He can be reached at email@example.com.