In a prime location in the nation's capitol, a six-story reinforced concrete building was to be converted into a luxurious condominium. To accommodate the building's new use, and the addition of pipes, ducts and conduits throughout the building floors, the Owner required the installation of slab penetrations up to nine-inches in diameter and square openings up to 18-inches in dimension. To do so, however, the Owner had to account for the resulting loss in concrete section and reinforcing steel bars that would occur at the penetrations. An effective strengthening solution was required.

Several strengthening options were evaluated for this project, but the most effective proved to be the use of externally-bonded carbon fiber reinforced polymer (FRP) composites. Close coordination between the Engineer-of –Record (EOR) and STRUCTURAL was necessary to meet Owner requirements. After the slab was cut as indicated on the drawings and then the number and layout of the severed steel bars at each penetration was determined, the layout was submitted to the EOR. After developing a strengthening criteria for each opening, the EOR forwarded the details to STRUCTURAL to design and install an appropriate strengthening repair using FRP composites. The amount and layout of FRP varied for each location depending on penetration size and location, as well as the number, size and layout of severed steel bars. An open channel of communication between the different teams working on this project facilitated a successful outcome and met the Owner’s goal of improving the section loss and being able to move ahead with the conversion to a luxury condominium.