Replacing a disintegrating steel culvert as part of a transportation improvement project in Wilmington, Massachusetts, has presented novel challenges to contractor J. Tropeano Inc.

Headed by Louisa Tropeano-Tanner, President; and her daughter, Dailyn Sullivan, Senior Vice President, the Woman Business Enterprise won the job with a bid of $2,228,858 to replace the 60-year-old Lubbers Brook Culvert on Middlesex Avenue (Route 62) and reconstruct about 10,000 square feet of roadway.

Tropeano’s director for the Wilmington roadway/culvert project is Tom Maimone, while his father, 30-year construction veteran Al Maimone, is the project superintendent. Father and son have worked together on several large and complicated projects.

In its bid, the Newton, New Hampshire WBE proposed a 45 calendar-day shutdown of the urban minor arterial between July 18 and August 30. This is the period of lowest brook flow, which would help keep personnel “working in the dry.” During construction the road was detoured, with Liddell Brothers (Roadsafe Traffic Systems) providing and installing a detour sign package on local streets and nearby Interstate 93. The contract called for Tropeano to have Route 62 open by August 31, 2022, the first day for public schools in the Town of Wilmington.

According to Tom Maimone, the new single arch structure is replacing two rotting corrugated steel plate pipes. Designed to handle a 25-year flood frequency, the three-sided box structure is a Contech Engineered Solutions ALBC 84 Aluminum Arch Culvert. Tom Hennessey, bridge consultant, represents the culvert supplier.

Unlike most culverts, which cross roadways at a right angle, this one has an unusual skew of about 53 degrees to the culvert headwalls at each end. “The culvert span is only about 25 feet; however, the skew and existing utilities make the span along the centerline closer to 60 feet,” said Maimone.

The contract also calls for designing and building a temporary support for existing subsurface utilities passing above the existing culverts. The support was to remain in place during construction. Open-cut vacuum excavation was mandated to reveal subsurface utilities, and a strongback beam structure was specified to be designed and built over the open cut. Nylon slings or equivalent items such as truck ratchet straps were to be hung from the beams to hold up the existing 18-inch-thick by 36-inch-wide concrete-encased Verizon ductbank. No utility service could be disrupted throughout the duration of construction.

Before the temporary support system for this ductbank could be constructed, Tropeano had to provide such relevant documents as design plans, calculations, details, shop drawings, and erection details, to the town’s engineering consultant, TEC Inc., for review and approval. The design of the temporary utility support structure had to be prepared and stamped by a Professional Engineer registered in the Commonwealth of Massachusetts.

Tropeano hired R.S. Audley Inc. to design and build the ductbank support. Dave Gifford, P.E. with Audley, designed a temporary 135-foot ductbank support. This was made up of a strongback beam comprised of two stacked HP12x53 girders supported on two bents. The bents in turn consisted of two vertical HP12x53 piles and a horizontal HP12x53 pilecap welded to the top of the two piles.

Audley used an H&M 3000 vibratory driver to install the piles about 15 feet deep. The existing concrete-encased ductbank is suspended beneath the strongback by ratchet truck straps placed 18 inches center-to-center. Each strap has a working load capacity of more than 2000 pounds.

One of the first tasks for Tropeano was controlling site water. This entailed diverting existing brook flow and lowering groundwater. “We have Rain for Rent pumps and sediment tanks onsite for dewatering and stream diversion,” said Maimone. To divert brook flow, workers erected a six-foot tall cofferdam consisting of 3000-pound bulk sandbags provided by U.S. Construction Fabrics. Since the project was being constructed during a low-flow period, two 6-inch self-priming dewatering pumps managed the brook flow.

To lower groundwater, workers set up four 3-inch submersible pumps that discharged to two open-top weir tanks for settling out solids prior to discharging into a temporary swale. The swale was meant to lower the velocity of the water as it was reintroduced to the brook. According to Tropeano, groundwater was exceptionally high in September, which caused pumps to be running 24/7.

The project required a Wetland Specialist to document compliance with the applicable permits. Jennifer Letourneau of J. Kehoe Consulting, LLC was selected for this role.

Tropeano self-performed site earthmoving using a fleet of Volvo excavators, loaders and off-highway trucks to remove some 3000 cubic yards of material. This included unsuitable material beneath the culvert footings that required a 24-inch over-excavation and replacement with crushed stone.

The Town took this opportunity to have force main and gravity sewer lines installed beneath the proposed culvert footings - a place where no sewer infrastructure had ever existed, adding system capacity for future use. In addition, one 12-inch water line that ran over the existing culvert was temporarily cut and capped by the contractor to allow construction to proceed. The water line is to be placed on a permanent galvanized-steel utility support situated outboard of the culvert on the downstream headwall.

There was also an 8-inch gas line running over the existing culvert which had to be temporarily cut and capped, this time by NGRID personnel. The gas line was installed outboard of the culvert on a support mounted to the face of the upstream headwall.

Work crews assembled the culvert in sections about 30 yards from its permanent location, then used a 300-ton, hydraulic Grove crane to lift the sections into place. The GMK 5250L crane, which the contractor rented from Chelmsford Crane, has a 150-foot boom but it performed the lifts at a 100-foot radius. The 93-foot-long culvert tips the scales at 29,400 lbs. including the weight of such accessories as 6500 high-strength bolts and reinforcing ribs. The crane positioned the culvert sections on footings prepared by Algar Construction. Algar is forming, tying in steel and placing an estimated 300 cubic yards of concrete for the culvert’s north- and south headwalls and culvert footings.

“The culvert footings were constructed using Contech Engineered Solutions’ Express Foundations, which are essentially stay-in-place galvanized steel forms with most of the steel reinforcement already installed,” said Maimone. “This allows us to set the form on the prepared subgrade, block up the keyway, tie a minor amount of steel, and place concrete.

“Not having to form footings in the foundation saved us a significant amount of time,” he said.

Maimone said Boston Concrete is the concrete vendor for the project. He pointed out that the 4,000- and 5,000 PSI MassDOT Cement Concrete routinely reached 150 percent of the design strength within 28 days. Rebars & Mesh provided approximately 15 tons of epoxy Coated Steel Reinforcement.

“The initial intent of our bid was to have Route 62 open prior to Wilmington Public School opening date of August 31, 2022,” Maimone said.

“This deadline was met. And much of the credit goes to the cooperation we experienced with town officials, their consultants, MassDOT, subcontractors, and materials and equipment suppliers, that made this challenging project a remarkable success.”

The project director attributed other important services:

• Bitcon Corporation (paving)
• Premier Fence (furnish/install bridge rail and guardrail)
• Auciello Iron Works (design/fabricate/permanent utility supports
• Miller Engineering & Testing (quality control testing and inspection)
• White Cap (miscellaneous construction supplies)
• EJ Prescott (pipe and fittings)
• Scituate Concrete Pipe (reinforced concrete pipe)
• Williams Stone (granite curb)