“The goal of the project is to rehabilitate the highway and bridge structures along I-691 in Southington, Middlefield, Cheshire and Meriden, Connecticut,” says Steve Haynes, Project Executive with Manafort Brothers of Plainville, Connecticut, the design-build contractor for the I-691 project. “Rehabilitation is necessary due to failing concrete pavement, obsolete safety features and reduced bridge load ratings. Project will ensure that the Hot Mix Asphalt riding surface and safety features are brought to current and appropriate design standards.”
The improvements include rehabilitating the pavement, including a cross-slope correction, along 3.5 miles, both eastbound and westbound in the center of the project; modifying the project parapets; repairing 15 bridge decks from exits four and eight; upgrading the guiderails; and adding new LED lighting and signage along the entire nearly 9-mile-long corridor.
Approximately 70,000 vehicles drive on this stretch of road daily. It began as a freeway in 1965 for U.S. 6A and converted to an interstate in 1987. I-691 connects Interstate 91 and Interstate 84. Exits will be renumbered to meet current Federal Highway Administration recommendations to label exits by the mile post from the origin.
The state of Connecticut funded the project. At least 15 percent of the work was assigned to small business enterprises.
“The design-build process streamlines communication between the designer and the contractor resulting in reduced risk for the owner,” says Justin Gill, Vice President of Manafort Brothers. “It also requires buy-in, constant monitoring and regular collaboration by all of the stakeholders. CTDOT District 4 staff and Manafort Project Executive Stephen Haynes and Project Manager Devin Widger embraced and promoted this approach throughout the project, and the results are a successful project that has overcome many challenges that could not have been anticipated.”
Design-build also offers opportunities for innovation. Manafort used Lidar surveying to facilitate the cross-slope correction, which provided increased accuracy by modeling the proposed pavement structure. It also translated to increased control during field operations.
The team also recommended using cured-in-place pipe lining to rehabilitate corrugated metal pipes, minimizing the disturbance of the existing subgrade.
“This eliminated weeks of traffic patterns and schedule duration compared to conventionally digging and replacing the pipe with conventional methods,” Haynes says.
WSP created a comprehensive traffic management plan, with much of the work taking place at night. One or two lanes of I-691 were closed while crews worked. Ramp detours have occurred for two or three nights per ramp on state roads. Manafort used three ProAll international mixers and rapid setting concrete on a nightly basis.
The team also had to deal with environmental concerns. “Part of the project is considered a limited work area due to the potential presence of protected plant or animal species,” Haynes says. “Manafort maintained compliance with permits and contractual conditions that limited disturbance in these areas.”
Manafort has completed the drainage upgrades. That work included “replacement of existing ACCMP (asphalt coated corrugated metal pipe) underdrain, rehabilitation of corrugated metal pipe crossings, and drainage structure modifications,” Haynes says.
Crews rehabilitated the existing concrete pavement and placed a polymer modified asphalt riding surface on top of it. Crews milled the existing pavement down to the underlying concrete base to locate failed areas, later removing and replacing concrete in those problem locations. They drilled and placed galvanized dowels into the adjacent concrete.
Crews also have finished the 15 bridge rehabilitations to improve load rating capacity. The bridge work entailed removing deteriorated concrete below the bituminous concrete wearing surface, performing deck patching, applying penetrating sealer and waterproofing, modifying the parapet at 52 locations, reconstructing the deck end at the elastomeric headers, replacing bridge joints, and applying 17,000 square yards of new membrane. They also performed haunch removal.
“One of the challenges has been that the quantity of concrete pavement repairs was higher than estimated in the contract,” Haynes says. “To mitigate some of the impact on the schedule, the Manafort team was able to increase resources by about 30 percent.”
Crews have installed the eastbound guiderail and poured foundations for the overhead and side mounted signs and lighting. Manafort also has placed the first of two courses of polymer modified asphalt.
Substantial completion is scheduled for December 2023.
“The project pursuit and much of design and construction occurred during the uncertainty of COVID-19 and the constant challenges of supply chain issues the industry has dealt with over the past few years,” Gill concludes. “We are most proud of the response from our employees and subcontractors. Our amazing trades people, supervisors and corporate office support staff have been extra vigilant to keep each other safe while diligently planning to keep project on track.”
Photos courtesy of Manafort Brothers Inc.