Prepared by the Capitol Visitor Center Project Office, Architect of the Capitol, December 9, 2002

This Week - Ongoing Work - 12/9/02 through 12/13/02

• The majority of CVC related construction activity is now occurring within the construction fence and the site is secured by the U.S. Capitol Police.
• Significant tunnel construction activity continues in New Jersey Avenue NW and along upper Northwest Drive. Additional tunnel work will begin in Constitution Avenue NW just east of New Jersey Avenue NW.

East Front Plaza Work (Inside the Construction Fence)

• Construction of the CVC foundation walls continues on the north side of the site. Concrete placement continues and two large construction vehicles fitted with “clamshell” buckets will continue to excavate the foundation wall trenches. Both clamshell excavation vehicles are situated on the north side of the site and one of the vehicles will begin work immediately adjacent to the east face of the Capitol this week.
• A plastic tarp will be suspended from the roof of the Capitol at various locations along the north side of the East Front to protect the building facade from construction vehicle emissions. During the next few weeks, the tarp will be suspended for approximately two days at any one location and it will be repositioned as CVC excavation work progresses along the East Front facade. The tarp is approximately 20 feet wide and it will obstruct windows temporarily on the First and Second Floors where it is situated. The tarp will not obstruct windows on the Third and Fourth floors although the ropes that support the tarp from the roof will be visible.
• Earth-moving and soil removal activities continue at several locations across the East Plaza.
• Crews continue to place concrete for the guide walls in the northern half of the site.
• Excavation for the guide walls continues on the House side.
• Foundation wall crews will work 24 hours a day on Wednesday and Thursday, Dec. 11-12, 2002.

House Side (Outside the Construction Fence)

• The construction fence near the House Steps and the drive loop adjacent to the fence have been shifted slightly to the south and west. Crews have relocated planters to clearly establish the new drive loop.
• Work continues at the south planter to replace the temporary barrier piers with permanent granite piers. The work is expected to be completed early this week.
• The South Door, the House Steps and the House Carriageway Door remain accessible to pedestrians throughout construction.

Senate Side (Outside the Construction Fence)

• CVC tunnel construction work continues in a portion of upper Northwest Drive and this work will last approximately 12 months.
• CVC tunnel construction work also continues along the east side of New Jersey Avenue NW between Constitution Avenue and C Street. Drilling and installation of earth retention beams will continue and will clear the way for construction of the tunnel walls. The east sidewalk in this location will continue to be closed, but the west sidewalk is accessible. The street will continue to be restricted to one lane and one way traffic traveling southbound.
• Crews have completed surveys of the north and south side of Constitution Avenue at the intersection with New Jersey Avenue NW to determine the locations of existing utilities. Excavation work related to the CVC service tunnel is expected to begin by the end of the week in the center portion of Constitution Avenue NW just east of the intersection of New Jersey Avenue NW. Parking spaces in this zone will be restricted so that two lanes of traffic can be maintained in each direction. Alternate parking arrangements have been coordinated by the Senate Parking Office. Pedestrian access will be maintained on both the north and south sides of Constitution Avenue. The tunnel work in this zone will continue for several months.
• Exploratory test pit drilling will begin on the plaza along the alignment of the CVC service tunnel. Parking and pedestrian paths will not be affected, although the work may eventually require some temporary traffic flow changes at the North Barricade Entrance. Any impacts to parking and traffic flow will be closely coordinated with the Senate Parking Office and the U. S. Capitol Police.
• CVC utility work will continue in the street at the intersection of Louisiana Avenue NW and New Jersey Avenue NW. Traffic patterns have been reconfigured to accommodate the crews, but traffic flow and entry into the Senate garage have not been impeded.
• Crews will dig test pits near the intersection of D Street NE and First Street NE to determine existing conditions in preparation for upcoming utility work in this zone.
• The North Door, the Senate Steps and the Senate Carriageway Door remain accessible to pedestrians throughout construction.

Next Week - Anticipated Work - 12/16/02 through 12/20/02

East Front Plaza Work (Inside the Construction Fence)

• Foundation and guide wall excavation and construction will continue in locations across the CVC project site. Some large equipment will continue to be situated close to the east face of the Capitol building on the north side. The East Front facade will be protected by a protective tarp that will be suspended from the Capitol roof along the portion of the building where excavation work is occurring.

House Side (Outside the Construction Fence)

• No work scheduled.

Senate Side (Outside the Construction Fence)

• Work will continue in a portion of upper Northwest Drive and along New Jersey Avenue NW for construction of the CVC service tunnel.
• Excavation will continue in the center of Constitution Avenue NW within the zone of CVC tunnel activity.
• CVC utility work will continue in the street at the intersection of Louisiana Ave. NW and New Jersey Ave., NW.
• Crews will continue digging test pits at the intersection of D Street NE and First Street NE to determine existing conditions for CVC utility-related work required in this zone.

Description of Foundation Wall Construction Process

Construction of the outer foundation walls for the CVC occurs in a series of steps. First, approximately 8 feet of the existing ground is removed along the perimeter (footprint) of the CVC to clear the way for construction of concrete guide walls. Guide walls are two parallel walls that measure 18 inches wide with a height that varies between 4 and 8 feet, depending on the existing elevation. The walls are aligned so that an approximate 3-foot gap is maintained between them. Once the guide walls are in place within a specific zone, a large red “clamshell bucket” is lowered into the gap between the walls and the bucket is used to excavate a narrow trench to an approximate depth of 70 feet. A muddy mixture called “slurry” is poured into the trench as soil is removed. The slurry maintains the stability of the side walls of the trench until a steel rebar cage is emplaced within the trench and concrete is poured. As the concrete fills the trench, the slurry is displaced, removed and reused. Once the concrete within the trench cures, a portion of the outer wall of the CVC is established. As the outer wall of the CVC is completed, excavation will continue inside the wall to a depth of approximately 50 feet. The slurry wall construction process, especially where it occurs adjacent to the Capitol Building, minimizes any potential disruption to the Capitol Building foundation, since the CVC foundation walls are formed and in place before deep excavation begins.

If you have any questions about the Capitol Visitor Center Project, please contact Tom Fontana, CVC Project Communications Officer for the Architect of the Capitol, at (202) 228-1310, or by e-mail at tfontana@aoc.gov

If you experience any problems with building services inside the Capitol, please contact the Capitol Building Service Center.