Three Bethesda Metro Center Garage Repairs

The parking garage at Three Bethesda Metro Center (3BMC) is a five-story below-grade cast-in-place concrete parking structure with the elevated slabs consisting of flat slab conventionally reinforced cast-in-place concrete deck construction. The garage is adjacent to a Metro station and below a Metro bus bay such that all work required extensive coordination with Washington Metropolitan Area Transit Authority (WMATA). A condition assessment of the facility revealed that the structural concrete slabs, beams, walls, and columns of the garage had experienced significant concrete deterioration due to corrosion of embedded reinforcing steel from over 30 years of exposure to salt laden moisture from vehicles. Open expansion joint gaps, unsealed cracks, and the lack of global waterproofing of the structural slabs contributed to the ongoing deterioration.

A comprehensive garage restoration program was designed, bid, and executed by a qualified local contractor with the work completed in phases while the building remained occupied and the garage partially open for use. Extensive partial and full depth concrete slab repairs including wall-to-wall partial depth slab removal on some levels was completed along with isolated vertical/overhead repairs to beams, walls, and columns with work performed on a unit price basis. Waterproofing steps included routing and sealing all large cracks and construction joints and sealing of expansion joint gaps. The project also included isolated work at the bus bay and plaza above the garage to address water leaks and concrete deterioration above. For long-term global protection of the structure, a corrosion inhibitor and a urethane-based waterproofing membrane system were applied over the elevated deck areas.