Boardwalk Getting New Foundation
When it’s built, it will be built to last. Although the when remains a mystery, the what has been settled: the boardwalk will be concrete and it will sit on new steel pilings.
The boardwalk – with the exception of the concession islands – will be brand new, end to end, top to bottom. The concrete remains that line the beach were tested for strength and durability and though initial results indicated the old pilings would be used as the foundation for the new boardwalk, later tests indicated they would age out somewhere between 20 and 40 years. The City wanted more. With the hundreds of millions of dollars being spent, the aim was for the structure to last at least 50 years with minimal maintenance.
According to Greg Clancy, a senior engineer with the Economic Development Corporation, the strength of the existing 90 year old concrete was “more than adequate” but with more tests and statistical sampling it was determined that salt was making its way toward the rebar (the steel inside the concrete) and would eventually corrode the steel. Corrosion would actually expand the steel and start to push out on the concrete, weakening it from the inside.
The new information made EDC and Parks rethink their strategy. They asked the design team, CH2MHill to rework the cost of a rebuild using new steel pilings rather than the existing concrete. It was determined that using the existing piles and figuring in down-the-road maintenance costs the price would come in somewhere between $30 and $60 million. The other option – new steel and a far lighter maintenance schedule – would cost between $35 and $45 million. Clancy said, “serious maintenance” with the new pilings would not be required for 75 years. When it was all added up, new steel pilings was the choice.
Currently, the concrete piles run 25 feet deep into the sand and stand 20 feet from each other. New steel pilings, sunk 30 feet in the sand, would be spaced at 30 feet. There will be fewer pilings as well. Clancy said the existing concrete structures have four piles; the new will have two though considerably wider than the original.
Clancy said the new pilings will allow the design team to consider a wider boardwalk to as much as 50 feet. The original, because of its cantilevered design, was limiting. While there are no plans to construct the entire boardwalk with a 50 foot width, Clancy said they are looking at “destination spots” where the boardwalk would extend further out.
The steel pilings will be coated with a green or black epoxy. Clancy said the pilings will not be visible because they will be buried in sand. “You’re not going to see them.” The underside of the boardwalk, Clancy said, will be full of sand and “offer another layer of protection.” It is expected that concrete planks, rather than poured concrete, will make up the boardwalk surface.
Clancy said no decision has been made regarding the existing concrete pilings, whether they will be demolished and removed or left in place and buried. A final decision will come after discussions with the Department of Environmental Conservation (DEC).
The islands at Beach 116th, Beach 106th, Beach 97th, Beach 86th and Beach 73rd Streets, constructed after Sandy, are using the existing concrete. If the engineering assumptions are accurate, the islands will need significant maintenance in 20-40 years.
The completion date remains a matter of speculation. Clancy said that too many variables are in play to offer a specific deadline date. Procurement, supply chains, and permitting are some of the unpredictable issues that affect timelines. The new steel pilings would take some 20 weeks to make – they are not “sitting in a foundry,” Clancy said. “It’s really hard to predict market forces. The day you hand over your purchase schedule is the day you get the real schedule.”
The plan is to begin building the boardwalk between Beach 86th Street and Beach 97th Street. Clancy said, “If we start construction in the spring – the bulk of the heavy work should be done in six months.” The 10 block stretch would be finished in a year’s time. Clancy added that other sections would begin concurrently. He said the second section to be rebuilt would likely be between Beach 97th Street and Beach 108th Street. The blocks where the boardwalk is currently intact would be the last to be replaced and rebuilt.
Clancy will make a presentation at the Community Board meeting on Tuesday, December 17th at 7 p.m. at Martin de Porres school on Rockaway Beach Boulevard.
As for aesthetics – what the boardwalk might look like – he said design teams were working to “put something together” in time for the meeting but wasn’t sure if that was possible given the short time since it became apparent that a new construction model was necessary.