U.S. Capitol Visitor Center

The most significant change to the grounds of the U.S. Capitol Building in 150 years was the addition of the 580,000-square foot Capitol Visitor Center. The new center is a three-level facility located completely underground and accommodates approximately 5,000 tourists.

As part of an award-winning A/E team, Volkert provided site engineering services including utilities design, topographic and utility location surveys, location studies and design of a variety of underground tunnels, and coordination with District of Columbia agencies.

The grand entrance area of the Capitol Visitor Center is 20 feet below ground with a drainage area of 3.3 acres.  To manage the large quantity of stormwater runoff directed toward the building, Volkert conducted hydrology and hydraulic analyses and designed a new drainage system. The design included two major holding chambers adjacent to the main entrance and twin reinforced-concrete gravity mains to convey the stormwater to an outfall sewer located 1,000 feet away from the underground facility.

Volkert designed the relocation of 2,210 linear feet of ductile iron pipe and appurtenances from the Capitol grounds to a new location. Utility design also included 2,500 linear feet of a new water main line for domestic water and fire services.


Washington, D. C.


Architect of the Capitol (AOC)