The Colchester I-89 Bridges Project is rehabilitating four bridges along I-89 in Colchester, Vermont. The four bridges are identified as 76 North and 76 South over Bay Road, and 77 North and 77 South over Mallett’s Creek. The project will replace the existing heavily deteriorated bridge decks with new precast deck panels. Concrete will be replaced on the bridge back walls and approach slabs, and minor steel and concrete repairs will be completed on the abutments and piers.
This project is time-sensitive and phased construction methods will be used to maintain two-way traffic on I-89 throughout the duration of construction.
Contract Award: February 2019
Construction Start: April 15, 2019
Bridge Closures: July 19 – October 7, 2019
Construction Completion: October 2019
VTrans Project Manager: Todd Sumner, P.E.
VTrans Resident Engineer: Chris Lavalette
Designer: VHB, Inc.
Contractor: Kubricky Construction Corporation
Public Information Consultant: Annabelle Dally, WSP USA Inc.
- The four bridges are located in the Town of Colchester in Chittenden County on I-89 between Exit 16 and Exit 17.
- Bridges 76 North and 76 South, over Bay Road, are located on I-89 approximately 3.8 miles north of Exit 16 at mile marker 95.3.
- Bridges 77 North and 77 South, over Mallett’s Creek, are located on I-89 approximately 1.3 miles south of Exit 17 at mile marker 96.6.
- Bridges 76 North and South are approximately 1. 3 miles south of the 77 North and South bridges.
The existing bridges are 3-span continuous rolled beam bridges constructed in 1964. Bridges 76 N&S over Bay Road are 157-feet in length and Bridges 77 N&S over Mallett’s Creek are 185-feet in length. All four bridges have beams and substructures that are in satisfactory condition, but decks that are in fair to poor condition with heavy deterioration in some areas, and leaky bridge joints. The bridge railings are not in line with today’s safety standards and need replacement.
VTrans evaluated alternatives for rehabilitation or replacement of the bridges in an engineering study completed in December 2014. The study assessed proposed design criteria for the bridges, along with impacts on rare, threatened and endangered species, archaeological and wetland resources. Several alternatives were considered including no action, minor patching, deck replacements, superstructure (deck, fascia, bridge rail) replacements, and full bridge replacements.
The engineering study recommended deck replacements with minor substructure (foundation, abutment, pier) repairs.
The decks will be replaced using Accelerated Bridge Construction (ABC) methods. The new full-width precast deck panels will be cast in advance off-site and then placed in 8-foot length segments. Each bridge will have two 12-foot lanes with a 4-foot shoulder on each side.
I-89 will remain open throughout construction. Crossover traffic patterns will be used on between July 19 and October 7, 2019, while the bridge decks are being replaced. There will be six weekend closures of the bridges during this period. The closures will begin at 7:00 PM on Friday and end at 6:00 AM on Monday. Two-way traffic will be maintained via crossovers.
- I-89 will be closed at Bridge 76N over Bay Road for 2 days
- I-89 will be closed at Bridge 76S over Bay Road for 2 days
- I-89 will be closed at Bridge 77N over Mallett’s Creek for 2 days
- I-89 will be closed at Bridge 77S over Mallett’s Creek for 2 days
The contractor will have 11 weeks to complete the six closures throughout the months of July, August, and September. For each weekend closure, the contractor will have 59 hours to complete work.
Weekdays during this period will use crossovers traffic patterns to maintain two lanes of traffic in the peak direction and one lane in the off-peak direction during high volume times of day.
This is the first time VTrans is implementing directional crossover patterns, as follows:
- One lane per direction during the weekend closures
- Two lanes southbound, one lane northbound during the weekday AM peak hours
- Two lanes northbound, one lane southbound during the remaining weekday hours
The timing of the crossover patterns was determined using traffic counts, and will occur at times of lower traffic to reduce congestion.
Navigational signage will be placed to guide motorists through the crossovers and changing traffic patterns.
On two weekends when the decks of Bridge 76 north and south are demolished, Bay Road and the bike path will be closed. A local detour will be signed.
Work on the project can begin as of April 15, 2019. However, the first bridge closure will not occur before July 19, 2019. All work must be completed in October 2019.