WASHINGTON — A billionaire history buff is donating the final $7.5 million needed to repair cracks atop the Washington Monument caused by last summer's earthquake that shook the East Coast.

Philanthropist David Rubenstein says he felt inspired to help after learning about cracks and chipped stonework high up the 555-foot obelisk from the 5.8-magnitude earthquake. The donation, first reported Wednesday by The Associated Press, is expected to be announced Thursday.

Congress allocated $7.5 million late last year, expecting a matching amount to be raised privately.

Daredevil engineers inspected the damage by slithering down ropes, and a report in December found the obelisk structurally sound but needing extensive repairs.

Rubenstein is co-founder of The Carlyle Group private equity firm. He says he wants the monument reopened to the public as soon as possible.