The State of Michigan Ottawa Building Complex was built in 1980. It consisted of an elevated landscaped area and two below-grade parking levels- one supported parking level and one slab-on-grade parking level. The supported parking slabs’ structural system typically consists of a structural steel beam and column framing with conventionally reinforced cast-in-place concrete slabs. The original 88,000-square-foot plaza surface included tree wells penetrating through the structural slab and surface plantings above the membrane. 

The parking structure had been exposed to chloride contamination from road salts and moisture that have progressively deteriorated the supported slab’s structural integrity and durability. WGI designed a full slab replacement including new lighting, fire protection, plumbing; new paint throughout; a heavy-duty low-odor deck coating system; new traffic control equipment; and new signage. 

A new plaza system, including a completely new membrane system, subsurface drainage isolation layer, cast-in-place floating slab, brick paving with an insulation layer, and snow melting system, was installed. The restoration included structural reconfiguration of specific deep well planters to become new walking areas and the installation of a complete subsurface drainage system to eliminate internal/subsurface water ponding.