This undated artist's rendering provided by the U.S. Tennis Association and architectural firm Rossetti shows the USTA Billie Jean King National Tennis Center, including a retractable roof for Arthur Ashe Stadium. The USTA says a retractable roof will be constructed over Arthur Ashe Stadium, the main venue for the U.S. Open. The Ashe roof is part of a larger plan to rebuild and expand other courts at the Billie Jean King National Tennis Center. No. 2 stadium Louis Armstrong will eventually be covered, too. (AP Photo/USTA and Rossetti)

NEW YORK, N.Y. - U.S. Open rain delays at Arthur Ashe Stadium will be no more by 2017.

The Grand Slam tournament's centre court could be covered by a retractable roof as soon as the 2016 tournament, but more likely the following year, U.S. Tennis Association officials said Thursday.

As the men's final was delayed to Monday each of the last five years, they had insisted a roof wasn't yet feasible financially or structurally. A decade after the USTA started studying the issue and three years after architectural firm Rossetti began researching the project, the price tag and the technology are finally workable. The construction will cost about $100 million, down from earlier projections of $200 million.

The U.S. Open becomes the last of the four major tournaments to cover up. The main stadiums at Wimbledon and the Australian Open already have roofs, and the French Open is planning one.

Flushing Meadows' No. 2 stadium, Louis Armstrong, will eventually be covered, too. Someday the Grandstand, the third-largest court, may be, as well.

The Ashe roof will be part of a broader, previously announced project to rebuild and expand other courts at the Billie Jean King National Tennis Center. The total price tag is estimated at $550 million.

The USTA must still receive final approvals from the city for the plans.

The organization had commissioned three different studies over the years that determined a roof wasn't feasible. The last time the USTA made a request for proposals, in 2009, it did not select Rossetti, the original architect for Ashe.

The firm "took it rather personally," said Danny Zausner, the tennis centre's chief operating officer.

"Behind the scenes, they worked on the project for free for a year to try to come up with a concept that no one else thought of," he said.

When Rossetti presented its findings to USTA officials in 2010, they were intrigued. Still, the firm was a long way from solving the riddle of topping Ashe.

As USTA executive director Gordon Smith put it: "It wasn't built for a roof, and the land conditions around it on the site are abysmal."

"We had to find out how to support 5,000 tons of steel on soil that is mush," said Matt Rossetti, the firm's head.

Using lighter materials atop the stadium was considered, but that proved unworkable. The USTA was willing to remove some seats, though not the entire upper bowl.

Technology innovations over the years helped in making what was once impossible possible, Rossetti said - in particular, computer modeling. But he estimated that 80 per cent of the shift simply came from the painstaking, time-consuming process of delving into different options.

A big breakthrough occurred just six months ago, when the firm surmised that the roof could be supported by only eight columns. At one point, the prediction was 32 — and there wasn't space for that at the tennis centre. It was only two months ago that Rossetti determined the eight columns would actually work.

Meanwhile, the rain kept falling at the Open. This year's men's final is slated for Monday from the start to spread out the tournament more and reduce the odds that Mother Nature wreaks havoc with the schedule.

The streak of bad weather didn't speed up the goal of a roof, Zausner said, though it certainly reminded USTA officials why they wanted one.

As recently as last year's tournament, they were still left explaining why they couldn't do it.

"I don't think it was as much pessimistic as frustrated," he said.

Players vented about starting and stopping matches and quick turnarounds as officials tried to squeeze competition in after delays. They didn't want to hear about poor soil and prohibitive costs.

"I can appreciate from their perspective: 'This isn't my problem. Fix it,'" Zausner said.

The USTA lost TV revenue money. The fans, though, were still coming.

"Even though we're selling record tickets, is it building frustration from our fans and our broadcast partners? There's no question," Zausner said. "But if we could have had this design five years ago and knew what we know today five years ago, I'm sure we would've had a roof five years ago."

The roof, made of a lightweight fabric, will take 5-7 minutes to close, though delays will last longer for drying the court. Zausner said the USTA couldn't learn much from Wimbledon and the Australian Open other than the best time for closing the roof, because the stadiums are so different.

The Grandstand will move to the opposite corner of the complex, with capacity increased from 6,000 to 8,000 fans. Armstrong, which currently seats 10,000, will be replaced with a larger version that can hold 15,000. The construction will allow for more and improved concessions than the two 50-year-old stadiums currently support.

New tournament and practice courts with additional seating also will be built so more fans can see the players in action; they could be complete as soon as next year's Open. As of now, only a few dozen spectators can squeeze in a view of the practice courts through a fence.

Walkways will be widened and esplanades created in an attempt to reduce the bottlenecks that frequently pile up between the main entrance and Ashe. The tennis centre's capacity for each day session will increase from 40,000 to 50,000 people.

The new Grandstand is scheduled to open by the 2015 Open and Armstrong by '18. Fans will see some of the work in progress; temporary bleachers likely will be used around the new Armstrong court at the midpoint of the two-year project.

The USTA will fund the project through bonds and increased revenue; officials said ticket prices would not be raised to pay for it.

A gap between the roof and stands will let in fresh air, and the stadium will be climate controlled. The challenge is to keep conditions similar for the players with the roof open and closed.

"I don't particularly like going from indoors to outdoors to indoors. It's also tough," defending champion Andy Murray said Wednesday at the Western & Southern Open outside Cincinnati. "But it's good for TV. It's good for fans that are watching. For the players that are scheduled on that court, it's great."

___

AP Sports Writer Joe Kay in Mason, Ohio, contributed to this report.

News from © The Associated Press, 2013