Innovative repair methods used on a South Florida high-rise corrected problems caused by poor construction practices. The building's floor structure consists of a two-way flat plate that is continuous with 8-foot cantilever balconies. The 8.5-inch-thick balconies surrounding the building perimeter were found to be structurally deficient. The top reinforcement was placed too low in the balcony slabs. Reducing the distance between the top steel and the bottom of the concrete slab reduced the slab's ability to resist cantilever forces.
After considering three repair options, it was decided to install steel or reinforced concrete brackets under the balconies. Holes ranging from about 16 to 19 feet long had to be cored into the edge of the slab. New reinforcement then had to be installed and simultaneously bonded into the holes. A 10-foot-deep stage was set perpendicular to the balcony. The stage was more than 20 feet wide, allowing two workers to drill at the same time. The stage was supported by four cables hung from support structures at the roof. A helicopter lifted most of the material for the support structures to and from the roof.
