What's next for I-93?
Motorists could be feeling the sting of the state's latest infrastructure problem for a long time.
The damaged bridge decking that has snarled traffic in and around I-93 North in Medford for two days, upsetting the travel plans for tens of thousands, will need to be completely replaced along with 13 other similar I-93 decks in the Medford and Somerville areas, Highway Commissioner Luisa Paiewonsky said late Wednesday.
"We have to replace it," she said.
Paiewonsky attributed the cause of a pair of large holes on the decking over Valley Street to the age of concrete and disruption of the bridge deck, with vibrations and heavy equipment, during a scheduled road resurfacing.
The deck is 50 years old and other decks on the interstate are about the same age and face the same problems associated with old concrete and wear and tear, the highway chief said.
"We had been aware of the deteriorating condition for some years now," Paiewonsky said, adding that the deck had recently been assigned for "accelerated" work.
Asked if it were a mistake to attempt the resurfacing project, which involved scoring the deck to ensure proper concrete and asphalt bonding, Paiewonsky said the resurfacing was needed to ensure the safety of 200,000 vehicles that use it daily. "The road takes a beating every day and you can't let it fall apart," she said.
"It's really the age of the bridge more than anything that explains this. Once you rip off a deck you never know exactly what you will find. The deterioration was more extensive than we knew about when it was all covered up."
When asked about the problems in Medford, which have triggered long traffic jams spanning the past two days, Gov. Deval Patrick cited "great progress" on overall state efforts to repair structurally deficient bridges and brought up the Big Dig, saying its financing had "starved" other public works efforts.
The problems in Medford started Tuesday when State Police reported two vehicles had sustained damage after encountering a "large hole" in the interstate. Transportation officials said Tuesday that they hoped to complete repairs by evening. On Wednesday morning, State Police reported four more vehicles had sustained damage and that the hole had reopened, but transportation officials said it was actually a different hole on the same deck.
Officials plan to replace the deck using what Paiewonsky called a fast-track design method involving pre-fabricated decks. The goal, she said, is to shave time off construction timelines. She said officials planned to hold the bridge together for the rest of the year and minimize loads while advancement replacement plans.
Design work on replacement plans could be completed by early winter, she said. The state owns the right of way and the project will not require relocation of utility infrastructure, factors she said will help speed the work.
Any work on an interstate will lead to delays and changes in travel patterns.
"Just even the most minor repair work we do out there can cause traffic headaches just because of the huge volumes," Paiewonsky said.
