Type: Expansion
Project Name: George Washington University
City: Washington
State: D.C.
Client: George Washington University

Features: 248-car space, 12-level horizontal expansion.

Description: Increased demand due to the new GWU Hospital building and local opposition to new parking structures determined the need to expand the existing University garage, a steel frame single helix structure with three below-grade levels, street level and seven supported levels for a total of 11 levels housing 1,000 parking spaces.
The one bay addition was position to accomplish three objectives: 1.) Easy access from the existing facility; 2.) Set back the structure as to avoid distributing loads into the underground Metro Rail structures; 3.) Meet District of Columbia lot occupancy requirements. Some of the challenges in this project were the immediate proximity of several existing structures including an underground Metro Rail station. One of the expansion?s walls was cast directly against a residence hall building with a shallow foundation.
All levels have one point of connection (entry/exit) with the existing facility where car count and full sign fixtures were provided to minimize confusion. The street level was sloped up to the existing slab. Accessible ramps were provided at both new and existing stairs and the new tower was fully glazed on the street side for security. The underground levels are sprinkled and mechanically ventilated while all other levels are considered as an open parking structure. Following an evaluation of structural systems, the University selected cast-in-place post-tensioned concrete for the Expansion for the improved schedule and constructability. DESMAN is the Architect and Structural Engineer of Record.