The I-89 Bridges Project is located at Exit 10 on I-89 in Waterbury.
The I-89 Bridges Project is rehabilitating aging components of the I-89 mainline substructure and replacing the concrete decks to extend the life of the Northbound and Southbound bridges and completely replacing the Exit 10 Northbound Off-Ramp bridge.
Mainline Northbound and Southbound bridges (46 N and 46 S) each have two travel lanes. The two mainline bridge decks had deteriorated to the point that concrete was starting to fall from the structure. The existing ramp bridge (46A) is a 6-span structure with five piers and expansion joints at each pier. Severe deterioration of the concrete piers on this Bridge coupled with the need for painting, and re-decking the bridge triggered replacement of this structure.
Work began in August 2014 to prepare for reconstruction of the two interstate mainline (Northbound and Southbound) decks and rehabilitation of the piers and abutments. The actual work on the mainline bridges was completed in 2015.
Work on the replacement bridge for the Northbound off-ramp began in 2016. A new ramp bridge will be built with two piers and three spans with continuous steel girders and expansion joints at the ends only. Reducing the number of expansion joints on the ramp bridge will reduce the potential for leaking at expansion joints, which causes deterioration of the bridge.
One of the two Southbound on-ramps is closed for a trial period and, if successful, this will become the permanent condition. For the other Southbound on-ramp, the acceleration lane has been extended onto I-89 to meet design standards for ramp design, which was previously substandard.
The northbound exit ramp is being widened to two lanes to provide additional capacity on the ramp because traffic backs up onto I-89.
A related project, Northbound Off-ramp Signal Project to replace the traffic signal at the end of the ramp was completed in August 2014.Adaptive signal controls were also installed as part of the I-89 project. These signal controls include control boxes and cameras to track traffic at each segment of the interstate. This data enables VTrans to trace the history of traffic patterns and adjust signal phasing to accommodate better traffic flow.
Construction of the I-89 Bridges Project has been sequenced from Fall 2014 to Spring 2017 because of the scope and complexity of the project. Sequencing of construction will also reduce potential impacts to the public.
Doug Bonneau, Project Manager
Vermont Agency of Transportation