Walter E. Washington Convention Center

At 2.3 million GSF, the convention center is the District of Columbia’s largest building, spanning six blocks, a distance of close to six football fields set end-to-end. This facility offers approximately 725,000 SF of exhibit hall space, 150,000 SF of meeting rooms and a 70,000 SF ballroom. The new convention center features the latest in technological advances including fiber-optic wiring and computer-controlled sound reinforcement for internal and external taping, and satellite up-links and down-links making worldwide communications possible. Also included was a central plant with enough power to support a town of 7,500 and emergency power to support 300 homes (most electrical power per square foot of any convention center in the United States).

One of the biggest challenges on this project was the shear size. To tackle the job, the project team was divided into smaller groups. One group focused on the design control, working with the architect to make sure the designs were within scope and on schedule. By monitoring the project first from the design end, the Clark team was able to notify the owner when any changes by the architect would affect the cost or schedule. Another group focused on the structure of the building, including the excavation, foundation, concrete, and steel. A third group focused on the internal systems, such as mechanical, electric, plumbing, telecommunication and vertical transportation. Two more groups in the team worked on the interior build-out and exterior site work.

A variety of challenges were faced while completing the construction of the project on a fast-track, 44-month schedule. Steel bridges to span the existing streets were constructed, utility relocations were made, and a tie-in to an existing Metro subway station was completed. The project is located in a busy urban area, so careful coordination efforts were implemented to ensure minimal disruption to the local traffic patterns. Community meetings kept local residents and business owners abreast of planned activities.

Clark Foundations implemented the largest excavation in the western hemisphere by removing 1.6 million tons of earth. For more than a year, 1,000 truckloads of earth were removed from the site each day. The foundation featured 225,000 GSF of slurry wall (the largest ever constructed in the Metropolitan Washington area). Located at the Mount Vernon Square Station downtown Washington, D.C., Clark installed 1,500 temporary and permanent tiebacks as well as rakers to support the 3’ slurry wall in order to minimize the movement of the active WMATA tunnel, located within just 16’ of excavation. The 3’ wide slurry wall was required to: 1) minimize the movement of an existing historical structure at the northeast side of the project site, within the influence of this 60’ deep excavation; 2) minimize the movement of an active WMATA tunnel located within 16’ of the excavation; and 3) act as a cutoff wall to minimize contaminated water discharge (one-third of the total excavation, or 1.4 million cubic yards, was contaminated).