With precast, Massachusetts sees a 55-hour fix for aging bridges

Warning drivers to expect significant delays, the state is encouraging motorists who do not need to get on or off in the Medford area to consider public transportation or skirt the affected area using Interstate 95 or other roads. The work site is in the path of thousands of Red Sox fans bound for Fenway Park and summer travelers heading north to New Hampshire or south to Cape Cod.

To forewarn motorists, the Department of Transportation has planted dozens of flashing message boards along the I-93 corridor and on other major roads to broadcast real-time conditions for the highway ahead, based on radar sensors and other methods for evaluating traffic. It is also directing people to consult the project website, 93fast14.com, or call the 511 traffic information line.

The state is also attempting to smooth travel over alternate routes that will carry spillover traffic, including retiming lights on Route 28 and postponing a Tobin Bridge lane-painting project. And it has worked with the Sox, Bruins, and performance venues to broadcast advisories to ticket holders.

The I-93 bridge replacement is drawing national attention for its ambitious timetable and use of precast elements, including hundreds of 60- and 80-foot-long blocks of concrete and steel fabricated in New Jersey and hauled in by flatbed truck, each section weighing 80,000 to 100,000 pounds.

Under the traditional method, rickety highway bridges are chipped away and rebuilt in place, a lane or two at a time, woven out of individual steel beams and rods later encased in concrete. That could consume four or five years for 14 bridges and require equipment to remain in place at all times, even during weekday rush hours, state Secretary of Transportation Jeffrey B. Mullan said.

Instead, all eight highway lanes will remain open on weekdays, but half will be closed from 8 p.m. Friday to 5 a.m. Monday on summer weekends through August, with a break only for the July 4 weekend. Each bridge is slated to be closed, demolished, rebuilt, and ready for traffic in a single 55-hour span, a choreographed sprint involving 100 construction workers and a battery of heavy equipment.

“We understand it’s temporarily disruptive, but as compared to several years that this project could take, I would take the quick delivery any day,’’ Mullan said.

Christine Mizioch, the state’s project manager, likened it to “trying to change the oil in a car while the engine is running,’’ when she presented the contract to the Department of Transportation’s board for approval in February.

http://www.boston.com/news/local/massachusetts/articles/2011/06/04/quick_fix_for_i_93_bridges_begins_large_traffic_jams_expected/