On Monday, the scaffolding surrounding the Washington Monument was topped off, and workers are set to repair damage from the 2011 earthquake. (Michael E. Ruane and Jayne Orenstein/The Washington Post)

After months of work and thousands of cross braces, screw jacks, frames, girts and super girts, the repair scaffolding around the exterior of the Washington Monument was topped off just before noon Monday.

The event was a major achievement in the mammoth $15 million project to repair the 555-foot-tall structure, which was damaged in the region’s 2011 earthquake.

Although some preliminary test repairs have been done on the stone structure, the real work had to await the scaffolding.

“That was a milestone to get those pieces touching at the very top,” project manager Robert Collie of Perini Management Services said of the pyramid-shaped top of the monument. “Now it’s a matter of all the detail work, which is going to take another few days.”

That includes fitting the bracing and bolting to make it solid, he said.

Covering the Washington Monument

The scaffolding started to go up in early February. Carol Bradley Johnson, a National Park Service spokeswoman, said the work was done by a crew of about 22 workers.

During a tour Monday inside the monument, which has been closed for almost two years, the structure had the feel of a grand tomb. Original chisel marks were visible in the stone, as was at least one earthquake-made crack.

The view out the observation windows 500 feet up was obstructed but still spectacular, with the Capitol, Lincoln Memorial, White House and Jefferson Memorial spread out below in miniature.

“Isn’t it amazing?” said James M. Perry, chief of resource management for the National Mall and Memorial Parks, who was born in the District and was a park ranger during the last repair project. “You could stand here for hours.”

The view was partially obstructed by the exterior aluminum and steel scaffolding — and, occasionally, by a worker, clad in hard hat and safety harness, clambering by, oblivious to the height and stiff wind.

There was also scaffolding on the interior, which was erected earlier, along with a tangle of wires and machinery.

“The scaffolding is only there to provide the platform for the stone repair,” Collie said. “We’ve given all this energy and all this attention to the scaffolding, and the real important part is yet to begin. ”

The exterior scaffolding also supports a hoist for workers and materials that goes up 500 feet. The remaining distance to the top is reached by ladder.

The scaffolding is not bolted to the monument, Collie said, but “squeezes” it like a vice, with wood-padded braces on all four sides every 26 feet up.

The marble-and-granite monument, which is the tallest free-standing masonry structure in the world, was extensively damaged by the 5.8-magnitude earthquake that struck the area Aug. 23, 2011.

The structure shook violently near the top and sustained cracks and loosened pieces of stone and mortar. Some cracks were so wide that daylight could be seen coming through. Cracks are being sealed with epoxy and reinforced with steel anchors.

Some unstable pieces were removed by inspectors in the weeks after the quake to prevent debris from falling. The removed pieces were saved, and engineers hope to fasten them back into place with stainless-steel dowels.

Where stone is missing, a patch called a “dutchman” can be cut from extra monument stone the Park Service has in storage or from a quarry that has previously provided stone, the Park Service has said.

No stones have to be completely replaced, but about 50 patches will be required.

Collie said some test replacements of mortar have been done, and test stone repair will probably be done next week. Formal stone repair will begin in about three weeks.

Much of that will be done on the scaffolding using 16 motorized “swing stages” — platforms similar to those used by high-rise window washers, Johnson said.

The monument, which is normally entered by about 600,000 visitors each year, is scheduled to reopen next spring.

The project is being funded by the government and a $7.5 million donation from local businessman and philanthropist David M. Rubenstein.

Collie said installation of a giant array of ornamental lights, designed to decorate the scaffolding during the project, has begun. Installation of a decorative blue-gray scrim is set to begin next week.

The scaffolding, lighting and scrim is much like that which enshrouded the monument during repairs in the late 1990s. The firms that worked on the project then are performing the work now, Collie said, and a lot of the same scaffolding has been used.

“I’ve done everything from hotel buildings to airport hangars,” he said. “In a career for a project manager, this is tops. Nothing gets better [than] doing something like a national monument, let alone the Washington Monument.”