The Middlesex Corporation designed and replaced six bridges carrying I-495 northbound and southbound over the Concord River, the MBTA commuter rail tracks, and Woburn Street in Lowell.

The staged construction required three lanes to remain open in both directions during all peak travel periods. To accomplish his, two temporary crossovers were constructed in the highway median to divert one lane of traffic into a contraflow lane in the opposing barrel. The Traffic Management Plan included temporary signals to handle traffic that was detoured past closed ramps.

Four bridges were re-designed from 3-span to 1-span bridges. Integral MSE abutments and wingwalls were designed and installed in lieu of the standard MassDOT cast-in-place abutments and wingwalls at four of the bridges. All demolition and erection were performed during nighttime operations. The project also required extensive interaction with the MBTA, MassDOT, Army Corps. of Engineers, DEP, and SuAsCo Watershed Community. Middlesex received an evaluation score of 99 out of a possible 100 from MassDOT.