Although its progress is largely hidden behind a 10-foot fence, the Capitol Visitor Center has reached some significant construction milestones.

The perimeter wall — measuring 2,080 linear feet — for the subterranean center is now complete. More than 400 truckloads of material are now being removed each day, and crews have excavated the site to half of its 50-foot final depth in several places and expect to begin erecting the first of 130 steel columns next month.

Over the weekend the concrete roof slab was placed on the tunnel that will connect the CVC and the Cannon House Office Building tunnel. The large cranes on the Senate side have disappeared, as walls for the service tunnel under Constitution Avenue are now in place. And after some setbacks due to extremely old infrastructure, almost all related utility work is done.

Yet although completion of the center isn’t expected until the end of 2005, other ramifications and questions have begun to loom as the project progresses.

Architect of the Capitol Alan Hantman recently told a Senate subcommittee that the AOC is putting off renovations for the Dome’s exterior until the CVC is complete. The first phase of the project, including repairs and painting of the interior, has already been finished. The second phase, which will include stripping the exterior paint down to the bare metal, was set to start soon. But after consulting with Congressional leaders, the Architect decided to put the exterior renovation off so as not to disrupt the vista of the Dome.

“They decided it would not be a good idea to have the [CVC] construction going on and the Dome encased in scaffolding,” AOC spokeswoman Eva Malecki said, explaining that officials wanted to give tourists at least one view of the Capitol, from the West Front, as it appears without construction.

In other CVC-related developments, Capitol Police Chief Terrance Gainer recently told both chambers’ Appropriations committees that the department anticipates it will need 135 more officers to screen visitors unless other doors to the Capitol and office buildings are closed to visitors to offset the eight new CVC entrances. Those numbers were included in the force’s fiscal 2004 budget request, which takes into account the department’s hiring needs beyond next year.

Defending what he admitted was a “robust” request before the Senate Appropriations subcommittee on the legislative branch last month, Gainer said the sheer number of entrances Congress wants open requires significant manpower.

“Given the number of doors and garages and entrances, that’s where a lot of this labor-intensive deployment comes in,” Gainer said. “And even as we get to [the] opening of the CVC, there’s no indication at this point that other doors and entrances would be closed.”

For years, Congressional leaders and supporters of the visitor center have billed it as a significant addition to campus security that would provide a centralized entrance for visitors. Much of the discussion surrounding the project had assumed that most, if not all, visitors would enter there, reducing the security strain at other points.

Although such dialogue is somewhat premature, there has been no substantial discussion recently of closing other doors to visitors when the CVC opens.

“So that all the technology and security that the CVC brings would just be added personnel,” Gainer told the subcommittee.

The chief said he would like to post three officers per entrance — both in the CVC and throughout the Capitol — “for deterrence and surveillance, one officer at a magnetometer, one officer at the X-ray machine and then another officer for surveillance behind that.”

“Some of that was born out of our experience when our officers were killed in 1998,” Gainer said of the shootings of officers Jacob Chestnut and John Gibson. “Putting two officers at a door is jut putting them at risk,” he added. Three officers per post was also recommended by a General Accounting Office study.

Another issue that has the potential to affect the visitor center is the remodeling of the west refrigeration facility at the Capitol Power Plant. The existing facility operates at maximum capacity during summer months, and if the project is not completed on time the plant will be unable to cool the CVC when it opens in 2005.

Hantman has requested $40 million to complete the project, which is projected to cost a total $81.8 million, and told the House Appropriations subcommittee on the legislative branch that it is “critical that this project be completed before the CVC is completed.”

A source familiar with the process said contractors bidding on the project have protested the price the AOC wants to pay.