On August 1, 2007, Minneapolis’ I95 W Bridge injured 145 people and took 13 lives when it collapsed into the Mississippi River. Seeing this disaster led Governor Patrick and Massachusetts transportation officials to reexamine the health of Massachusetts’ bridges.
What they found was disturbing: 61% of our bridges were built before 1960, and 42% were between 40 and 60 years old. The Commonwealth’s infrastructure was decaying quickly: 543 of 4,522 bridges were structurally deficient in 2008, and the Highway Department projected that, without a package of reforms, this number would rise to 700 by 2016. Although structural deficiency did not necessarily mean that the bridges were unsafe, it did show that they needed immediate repairs to prevent travel restrictions.
To address this disconcerting trend, Governor Patrick signed Chapter 233, Acts of 2008, which committed $3B to an 8-year Accelerated Bridge Program (ABP). The ABP’s central goal was to reduce the number of structurally deficient bridges to 450 by 2016. It also planned to use performance measurements, regular public reports and innovative initiatives to streamline the bridge-building process.
Over the next several years, “innovative” became a word often applied to the ABP, as cutting-edge technologies and new construction materials allowed MassDOT to replace bridges more quickly and efficiently than ever.
Bridge in a Backpack
On June 9, 2011, Governor Patrick, transportation officials and local leaders met at Fitchburg’s Scott Reservoir Outlet to monitor the progress of a special APB project. Using a system developed by the University of Maine’s Advanced Structures and Composites Center, construction crews were building a bridge unlike any in the Commonwealth.
This “Bridge in a Backpack” relies on reinforced composite arch tubes that are filled with self-consolidating concrete and backfilled. The tubes are extremely lightweight and are ultra-portable, but are much stronger than steel. In Fitchburg, they were transported to the site in small folded packs, and carried into place by 5 workers. The project required no expensive machinery, no costly materials and no time-consuming construction processes. Its technology was fast and efficient, and MassDOT expects the durable fiber-reinforced arches to outlast traditional steel and concrete elements.
Another jewel of the ABP was its 93Fast14 project, which demolished and replaced the superstructures of 14 bridges along I-93 in Medford. Using traditional construction techniques, construction crews would have taken 4 years to complete this project. However, several ABP innovations let them do the same work in only 10 weekends, from June 1, 2011 to August 30, 2011. These new techniques included:
- Simplified design/build procurement processes
- Prefabricated bridge elements, built in a carefully controlled off-site facility
- Rapid-setting concrete
During the project, MassDOT worked hard to limit traffic interruptions. Under normal circumstances, drivers would have faced long-term lane closures, frustrating jams, and other incidental inconveniences. While the project required crews to close parts of Interstate 93, as well as some local roads, it did not impact rush hour traffic at any time. As most of the superstructure parts were built off-site, on-site construction was minimal, quick, and smooth. All major construction occurred during weekends, and with a strong communications plan, weekend delays were considerably less than usual for a project this size.
Four Years of Progress
In only four years, the ABP advertised 177 projects, and completed over 115, ranging from maintenance and preservation efforts to full-scale replacements. Work has also begun on two of the program’s five “mega projects”: Lake Quinsigamond’s Kenneth Burns Memorial Bridge and Quincy’s Fore River Bridge.
The program’s successes have brought it national acclaim. At its start, ABP bonds received the Commonwealth’s first AAA rating from Moody’s and S&P. Later the program received Bond Buyer’s ‘Deal of the Year Award’. In 2011, the American Association of State Highway and Transportation Officials (AASHTO) chose the ABP to receive its Francis B. Francois Award for Innovation and a Performance Excellence Award. Most recently, the ABP received three awards from Engineering News Record (ENR) New York: Best Overall Project of 2012, Best Transportation Project and a Safety Merit Award. Other accolades include a front-page New York Times review, “Did Someone Order an Instant Bridge?,” which features the River Street bridge replacement in Hyde Park.
MassDOT is proud of the Accelerated Bridge Program. The initiative represents the organization’s commitment to self-improvement, its willingness to embrace unconventional solutions, and the benefits of careful planning and coordination. It also showcases MassDOT’s continual commitment to leading the nation in transportation excellence.