The banging and ringing sound of metal piles being driven into the floor of the Thames River around State Pier, echoing through the streets of Groton and New London, has ceased.

The silence marks a significant milestone in the nearly $310 million reconstruction of New London’s deepwater port, signaling near-completion for what has become a staging and assembly hotspot for the country’s burgeoning offshore wind industry.

The last pile was driven on March 13, and dredging around the pier wrapped up in February, later than initially anticipated but still in time to accommodate the arrival next month of offshore wind turbine components for Ørsted and Eversource’s next project, Revolution Wind.

“To the residents of New London and to the residents of Groton, I thank you for enduring all of the pile driving during the day and night ... for the benefit of the rest of the state and the country,” Ulysses Hammond, interim executive director of the Connecticut Port Authority, said at a port authority meeting earlier this week.

Hundreds of the piles, which are metal pipes ranging in diameter from 30 to 42 inches, were used to shore up the newly constructed pier. Marlin Peterson, construction manager for AECOM, said there are more than 1,000 of the piles, including the piles to create walls containing the 390,000 cubic yards of fill material used to fill in the 7 acres of water that used to separate two piers.

Hammond said contractors are in the final stages of preparing for the arrival of offshore wind turbines associated with Revolution Wind, a 65-turbine offshore wind project to be construction off the coast of Rhode Island by partners Ørsted and Eversource -- the first project to deliver power to Connecticut. State Pier already was used to marshal components for South Fork Wind, a 12-turbine project that became the first utility-scale offshore wind project in the country and is now supplying renewable power to the Long Island grid.

Hammond said the construction project will be substantially completed by April, with some lingering punch list items being performed on site. Over the next several weeks, work crews will be installing fenders, bollards and ladders along the pier installation berth. There is also drainage piping and salvaged granite blocks to be reset, final grading and compaction, Peterson said.

Increased costs

The construction work, especially the pile driving, has proved to be more challenging and costly than expected. Works crews have repeatedly reported hitting obstacles, such as boulders and buried structures, while driving the piles, leading to longer work hours and more time on site for the massive pieces of equipment being used. Peterson said crews were often working six days a week and two 10-hour shifts.

At a special meeting on Tuesday, the port authority’s board of directors authorized spending $1.5 million on the work, $870,000 more than anticipated ― more than half of that added cost is associated with pile driving. The port authority had approved the extra work but had not yet had details of the final cost. Peterson said other expenses include the installation of a larger water connection, safety buoys and dealing with the discovery of sewer manholes on site.

The money is coming from the $6 million in the budget earmarked for contingencies. The rest of the money is also likely to be spent when the final costs of installation of toe walls, which Peterson said construction manager Kiewit Corp. thinks will exceed the remainder of the funds. Peterson said AECOM contends the contingency will cover the cost but remains in negotiations with Kiewit.

“We’ll see how we come to a resolution to that discrepancy,” Peterson said.

The construction project, when conceived in 2018, was estimated to cost less than $100 million but has steadily risen in cost. Last summer, the Connecticut Port Authority obtained $30 million more from the state and $23.7 million from Ørsted and Eversource to cope with the cost increases.

Ørsted and Eversource, with three planned projects associated with staging and assembly at State Pier, are paying the port authority $2 million a year as part of a 10-year lease of the property. Separately, the city of New London is receiving a minimum of $750,000 per year as part of a host community agreement with Ørsted and Eversource.

David Kooris, chairman of the board, said if the contingency funds are not enough to cover the final costs, there is funding available from other revenue streams, including the lease payments from the New England Central Railroad property next to the pier.

“We’ve got all the money we need. We’re not going back (to the state) for more money,” Kooris said.

g.smith@theday.com

State Pier Rebuild – By the Numbers

335 – 30-inch diameter Pipe Piles

367 – 42-inch diameter Pipe Piles

323 – Sheet piles

2,525 – lineal feet length of Toe Wall (combination of pipes & sheets) used to retain rip-rap below the water line along east wall

390,000 – cubic yards sandy fill between State Pier & CVRR Pier

180,000 cubic yards dredged volume (disposed offsite)

8,643 – lineal feet of stormwater pipes

4 – new Stormwater Outfalls

10 – 120-foot High-Mast Light Poles

14,500 cubic yards of concrete

4,812,866 lbs. of steel reinforcement (rebar) which equates to 2,406 tons

(Source/ Connecticut Port Authority)