VAI Architects, acting as consultants on behalf of Dallas County
The four-and-a-half-story underground parking garage beneath the John F. Kennedy Memorial in downtown Dallas, Texas, was constructed in 1968. The below-grade parking garage has a 46,000-square-foot footprint and features 54-foot-long prestressed, precast concrete single tee-beams. Post-tensioned concrete slabs span perpendicularly between the single tee-beams and are continuous over the beams to create a monolithic floor slab. The post-tensioning system consists of button-head anchored individual wires. The beams are framed into corbelled cast-in-place concrete columns. The perimeter walls primarily consist of cast-in-place concrete.
WJE's investigation included a survey to document the cracks, leak locations, and distressed T-beam bearing locations as well as inspection openings to determine the thickness, strength, and composition of the structural concrete and to observe the exterior waterproofing. In addition, WJE created an exploratory opening at the street level to determine the condition of the plaza waterproofing and installed a piezometer to document the elevation of the water table at the site. Subsequently, WJE was retained by VAI Architects to develop repair documents based on the findings: limited sidewalk removal and repair of the plaza waterproofing; repair of post-tension strands; routing and sealing cracks; pressure injecting cracks in the elevated slabs; removing and replacing distressed concrete; and other routine maintenance items such as painting and restriping the garage.