Capitol Visitor Center project nears halfway mark

The ninth — and largest — addition to the U.S. Capital in Washington, D.C., is more than 40% complete, with part of it on track to provide a platform for the presidential inauguration ceremony in January.

The underground Capitol Visitor Center (CVC), which is under construction adjacent to the Capitol's East Front, will be the new entry point for visitors. It will encompass 580,000 sf on three below-grade levels, and also include 170,000 sf of expansion space for the House and Senate. The project has a five-acre footprint that is larger than the Capitol's current footprint.

About 3.5 million people visited the Capitol in 2000, the last full year before the impact of 9/11. The number of visitors was cut back after the terrorist acts, and recently climbed back to about 8,000 per day. The CVC is designed to comfortably accommodate 12,000 persons a day, and 4,000 at one time. The Capitol itself has been the tour bottleneck, because of inadequate rest rooms, stairways, elevators and other facilities to handle a large volume of visitors.

CVC features will include a 600-person dining facility, 25 passenger elevators, 26 restrooms, and two orientation theaters where visitors will view an introductory film before beginning their tour. The CVC will enable visitors to be screened at a distance of 400 feet from the Capitol.

The visitor center will be supported by 135 steel columns and 50 concrete columns. Steel columns were specified to assure that the area of the plaza on which the inauguration will take place is ready by January. However, $600,000 was saved by using concrete for the remaining columns, according to project officials.

A formal turnover of the project from Dallas-based Segment I contractor Centex Construction Co. to Segment II contractor Manhattan Holdings Inc., Tulsa, Okla., occurred last month. Centex's work, under a $100 million contract, included excavation and construction of foundation walls, the roof slab, and a service tunnel. Manhattan Holdings will build out interior spaces and install electrical, mechanical, and plumbing systems under a $144 million contract. Gilbane Building Co., Providence, R.I., is the project's construction manager.

The overall $351 million project budget includes a base cost of $265 million, as well as $38 million for security enhancements after 9/11, and $48 million to accommodate unforeseen site conditions.

Baltimore-based RTKL Associates is the project's architect. Other design team members include structural engineer Weidlinger Associates, New York City, and mechanical engineer James Posey Associates, Baltimore.

In the wake of the 2001 terrorist attacks, the CVC's mechanical systems were made more robust and capable of operating independently from systems in the Capitol.

The project required the excavation of 50,000 truckloads of soil, the construction of 2,100 linear feet of slurry wall, and the operation of heavy equipment within 3 feet of the Capitol. Slurry walls were not needed, however, near the East Front stairway, where columns and a concrete foundation, constructed as part of a 32-foot extension completed in 1962, extend to a depth of 70 ft.

The CVC will be covered by a 2-foot-thick roof that incorporates a 13-inch structural slab and a 6-inch work slab. Granite paving stones that form an outdoor plaza will top the facility.

Close monitoring of the project to detect any damage to the Capitol included pre-project photo documentation of the Rotunda. More than 100 metal rods installed throughout the Capitol are surveyed weekly to ensure that construction activity is not affecting the building.

The project is targeted for completion by spring 2006. Its initial December 2005 completion was pushed back by a number of factors, including extensive relocation of site utilities (a $7 million item), abnormally high rainfall, and tighter security measures instituted after 9/11.

Two tunnels are included in the project. One is a 1,000-foot-long conduit for truck deliveries. The other will connect the CVC with the Library of Congress across the street.

To lessen the amount of construction noise that enters Capitol offices, 140 East Front windows were overglazed at a cost of $350,000 — an expenditure that was considered justified when weighed against the potential for disrupting construction in order not to interfere with legislators' activities.

The Capitol Police have performed more than 5,000 background checks on on-site workers.

Project updates are available at www.aoc.gov, then by clicking on "Capitol Visitor Center."