MassDOT's "93Fast14" project achieved an historic success this weekend as work crews erected the final of 14 prefabricated bridge superstructures on I-93 in Medford. The 14 deteriorated bridges that carry Interstate 93 over seven local roads in Medford have been replaced at a rate of at least one bridge per weekend this summer. In every case, the work was completed and all roads reopened several hours ahead of schedule, well in advance of the Monday morning commute.
Federal Highway Administrator Victor Mendez called the 93Fast14 project the most ambitious bridge project in the country. The project under normal circumstances would require at least 4 years of construction and lane closures. MassDOT used cutting-edge techniques to safely complete the project much more quickly, including:
• Design/Build: one joint venture team (J.F. White/Kiewit) is responsible for both design and construction.
• Pre-fabricated bridge element system (PBES): a total of 252 prefabricated panels made of two steel I-beams with a concrete deck replace the old superstructures. They are prefabricated in a controlled, factory setting which results in high-quality concrete. Once at the construction site, they are lifted into place using cranes.
• Special “closure pour” concrete mix: This project uses a special rapid-set concrete for the “closure pours”— areas of poured concrete which connect the prefabricated panels.
• “Zipper Lane” crossover: provides a safe work zone for drivers and workers and allows for the bridge demolition and replacement to occur in just 55 hours (or less).
The $98.1 million project to replace the fourteen bridge superstructures in Medford is funded through the Patrick-Murray Administration’s historic Accelerated Bridge Program, a $3 billion recovery effort to reduce the Commonwealth’s backlog of structurally-deficient bridges.
Completing the final superstructure erection this weekend is a major milestone for the project team, but work will continue. During the last two weekends of August, MassDOT will perform weekend work requiring lane restrictions. Construction activities will also continue to occur during off-peak hours during weekdays and weekends after August.
For more information on the project, visit the 93Fast14 website.