Award of Excellence: Parking Structures
East House Underground Garage Rehabilitation
Submitted by Restoration East, LLC
Architect of the Capitol
Restoration East, LLC
Advanced Polymer Technology
The East House Underground Garage was constructed in late 1969 to provide parking for 700 congressional representatives, staffers, and visitors. Located in southeast Washington, DC, only two blocks from the U.S. Capitol Building, the below-grade garage has an 87,500 square feet (8130 square meters) footprint spanning an entire city block.
The owner engaged an architectural and engineering firm
to perform a comprehensive condition investigation of the parking garage to determine the extent and causes of the concrete deterioration. The investigation integrated nondestructive chain drag surveying to locate voids with destructive coring to determine chloride-ion content and
the compressive strength of the structural concrete. The existing condition survey also incorporated a mechanical evaluation, electrical assessment, fire protection consideration, and plumbing efficiency evaluation.
The architectural and engineering firm prepared comprehensive specifications and design documents for the structural rehabilitation, as well as a complete renovation of peripheral building implements that included life safety systems—mechanical, electrical, and plumbing systems and all of the finishes. The contract was awarded under a best-value procurement.
The completed garage repair scope of work included: 172,000 square feet (15,980 square meters) of wall-to-wall hydrodemolition of the top 5 in. (127 mm) of the elevated slabs; graded concrete overlay to provide superior drainage; revitalized storm sewer design; 41,000 square feet (3809 square meters) of full-depth, 10 to 12 in. (254 to 305 mm) thick slab repairs; repair and modification of the foundation wall corbels that bear the elevated slab perimeters; replacement and augmentation of 42 tons (38 metric tons) of slab reinforcing steel; concrete repair of walls, columns, curbs, and ventilation shafts; application of traffic bearing membrane on elevated slabs; and replacement of all structural slab expansion joints.
Additionally, the project was originally designed to meet the U.S. Green Building Council (USGBC) LEED Silver guide- lines. Ultimately, the team was able to work together to obtain a Gold certification.