WASHINGTON (AP).- A billionaire history buff has stepped forward to donate a $7.5 million matching gift that's needed to start repairing cracks near the top of the Washington Monument caused by last summer's East Coast earthquake.

Businessman David Rubenstein said he was inspired to help fund the repairs to the 555-foot obelisk when it became clear how severely damaged it was by a 5.8-magnitude earthquake Aug. 23. The National Park Service and nonprofit Trust for the National Mall announced Rubenstein's gift Thursday morning. It is the largest gift to the nonprofit group, which aims to raise $350 million to restore the mall's grounds and facilities.

Rubenstein came forward very soon after the earthquake.

"I would suggest it hadn't even stopped shaking before David Rubenstein came to me and asked if he could help," said National Park Service Director Jonathan Jarvis said.

The famous landmark received about 1 million visitors a year before it was closed to the public after the quake. The Park Service hopes to have a contractor begin work by the end of August.

Bob Vogel, superintendent of the national mall, said the park service is working to get the monument reopened as quickly as possible. He said repairs will likely take a year to complete, but such an undertaking has never been done before, so the exact timeline is uncertain.

"This is a complex job," Vogel said. "This is a one-of-a-kind structure that poses challenges for repair that other buildings don't."

Congress allocated $7.5 million in December on the condition that private donations would match that amount. The combined $15 million in public and private funds is expected to cover the cost of repairing damage directly caused by the quake, said National Park Service spokeswoman Carol Johnson. Repairing water damage will cost more, as would a seismic study or reinforcements to strengthen the structure against future earthquakes, she said.

Rubenstein is a co-founder of The Carlyle Group, a private equity firm.

"This Washington Monument is probably one of the most recognizable buildings in the United States next to the Capitol and the Empire State Building," he said. "It could use a little repair work, and I wanted people to get to see it as soon as possible."

He also acknowledged some of the large gifts he's made in recent years to the Smithsonian Institution, the National Archives, the Library of Congress and the Kennedy Center. Last month, Rubenstein gave $4.5 million to the National Zoo to fund its giant panda reproduction program for five more years.

"I don't think I want to be buried with my wealth," he said. "I want the pleasure of giving it away while I'm alive."

The August quake was centered some 40 miles west of Richmond, Va., and felt from Canada to Georgia. It damaged the Washington National Cathedral, where pieces of mortar rained down from its vaulted ceiling. At the Washington Monument, panicked visitors fled down flights of stairs on the day of the big shake, but there were no deaths or serious injuries in the region.

The earthquake caused numerous cracks to form in the obelisk, which was the tallest man-made structure in the world when it was completed in 1884.

Surveillance video taken the day of the quake showed the spire shaking violently. Daylight could be seen through some of the cracks, the largest of which was reported to be at least 4 feet long and about an inch wide.

A report in December recommended extensive repairs and reinforcements to preserve the spire. It said some marble panels were cracked all the way through near the top portion of the monument. Cracks near its peak also have left the monument vulnerable to water damage from rain, engineers noted.

Last fall, daredevil engineers rappelled from the top to conduct a visual inspection of the exterior. They documented the damage but noted the monument is structurally sound.

Officials said it's unclear whether the work will require scaffolding to be built around the monument, similar to what was erected during a restoration project from 1999 to 2001.

Caroline Cunningham, president of the Trust for the National Mall, said Rubenstein's gift "demonstrates how much people care about this space."

There has long been talk of sprucing up the mall at the heart of the nation's capital.

A design competition is under way to develop ways to improve the mall, including the Washington Monument grounds. Finalists will be chosen in May, and the group will seek funding for each project. The nonprofit group has targeted parts of the mall that are run down from over use and neglect as a focus for its restoration efforts.

The monument was built with private $1 donations eventually totaling over $1 million, Rubenstein said. Construction began in 1848, but funds ran out during the Civil War when the monument was left as an embarrassing stump for years. It was finally completed in 1884 and was the world's tallest man-made structure until it was eclipsed by the Eiffel Tower. It remains the tallest structure in Washington.

Rubenstein owns a copy of the Magna Carta, among other historical documents, and reveres George Washington.

"I like to remind people about American history," Rubenstein said. "George Washington is an incredible figure. When he was the head of the Revolutionary War Army, he could have stayed on as really the head of the government when we won the Revolutionary War, but he put down his arms."




Copyright 2012 The Associated Press.