The overall concept is to construct the median bridge and transfer one barrel of the highway to it and reconstruct the relocated barrel.
(Photo courtesy of NHDOT.)
Work to rebuild two bridges on Interstate 89 in Lebanon, N.H., which began in 2020, is nearing the halfway point, with progress to report.
"Approximately 47 percent is complete for monies and time," according to New Hampshire Department of Transportation (NHDOT), which said the budget for the project is $43.8 million that will be paid by state and federal funds, including a $10 million U.S. Department of Transportation Tiger Grant, according to Eileen Meaney, an NHDOT spokesperson.
Work to rebuild the north and southbound bridges involves constructing a new bridge to replace the existing bridges, which were included on the state's red list before new construction started.
"The overall concept is to construct the median bridge and transfer one barrel of the highway to it and reconstruct the relocated barrel," NHDOT said. "The work trestle is complete. Pier cofferdam installation is complete for all five piers, removal completed for all piers except Pier 4."
The "infill" abutments are complete and the new piers for the "infill" bridge are complete. There are five piers, four in the river and one on the embankment between the river and the railroad tracks.
The "median" bridge's structural steel has been erected, but minor work associated with it will continue.
Some of the precast deck panels have been erected, from Abutment B (NH) to Pier 2.
Scott Stevens is vice president and bridge engineer of R.S. Audley, Bow, N.H., the lead contractor on the project.
"We'll build the infill bridge between the north and southbound structures then rehab the other two structures, so they'll all come together as one big bridge," he said. "We'll demolish the bridge deck, remove the structural steel and rehabilitate all existing piers and abutments and set new structural steel to connect it to the infill. Then, we will construct a new bridge deck on top of the new structural steel and when we're finished all three portions will be connected as one integral bridge."
When noted that the five-year time frame indicates the job will not be completed until 2025, Stevens said, "It's a big job, but a portion had to be redesigned, which slowed us down by about eight or nine months, but we're doing our best to get things back on track."
H.B. Fleming of South Portland, Maine, was the contractor on the trestle work. Scotty Linscott is the owner of the company. "We built the trestle across the river that allows access to build the piers and set bridge girders," he said.
Hub Foundation of Chelmsford, Mass., built and installed the micropiles.
"The pier rock was more sloped than they planned when they poured the concrete, so we installed micropiles through the footing," said John McKinnon, Hub Foundation manager. "We drilled in the rock, so the footing is supported by micropiles."
R.S. Audley is using a Link-Belt TCC-1400 140-ton crane on the project as well as a Grove RT60 65-ton rough-terrain crane and a Manitowoc YB5515 15-ton carrydeck crane.
Hub Foundation used a Davey Kent 525 diesel drill rig and a Penn 10-10 cement mixing plant.
Subcontractors on the project include Casco Bay Steel Structures, South Portland, Maine, as the steel supplier; Continental Paving, Londonderry, N.H., as the paving contractor; and Carroll Concrete, Newport, N.H., as the concrete supplier.
R.S. Audley also is self-performing the excavation and concrete forming and placement and steel erection work. It will shut down near the end of January due to winter weather and will restart approximately March 1.
The new bridge will be 840-ft. long and 110-ft. wide, which is two acres of bridge, according to Stevens. He called it "a complicated job" that will require 3.5 million tons of structural steel, 500,000 lbs. of uncoated reinforcing steel and 600,000 lbs. of epoxy coasted reinforcing steel. It also will utilize 5,000 cu. yds. of concrete, which makes it "a significant bridge project for New Hampshire." CEG
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