The new headquarters of the Abu Dhabi Financial Centre (ADFC) includes four high-rise office buildings comprising 285,000 square meters of dedicated office space. ADFC is part of Sowwah Square, a 570,000-square-meter office and retail space development. Construction began in the summer of 2007 with a phased completion date starting in 2010.
The main contractor for the ADFC wanted to strengthen several concrete corbels located in the podium level of four towers. After the structural engineer reviewed the design, it was determined that the existing load capacity was not sufficient and there was a deficiency of reinforcement in the corbels. A solution was needed to increase the strength of pre-pour corbel that could be employed parallel to, and with minimal effect on, existing construction work at ADFC.
Preliminary evaluations were compiled and the project team opted to use externally bonded Carbon Fiber Reinforced Polymer V-Wrap (CFRP) and concrete enlargements. Externally bonded CFRP was selected, because it offered ease of construction, minimal modification to the structure and schedule, and kept the project within the estimated budget. STRUCTURAL was contracted to perform the corbel strengthening.
Twenty-six of the corbels were strengthened using CFRP V-Wrap for a total of approximately 200 square meters of CFRP installation. After the CFRP was installed, an additional coating of FRL intumescent paint was applied over the system to provide additional flame/smoke spread resistance as required by the local code.
Concrete Enlargement
Two corbels were strengthened using concrete enlargement techniques with pressurized form and pump techniques. Concrete enlargement was the necessary solution for some of the corbels, because the required strengthening could not be achieved using CFRP V-Wrap systems.
One of the main challenges on this project was that the as-built and field conditions differed from the design. Some corbels were smaller in width than shown on the design drawing. STRUCTURAL performed an as-built survey of all 28 corbels to verify the field conditions and re-designed some of them repairs to accommodate the variations in the corbels and strengthening requirements. Additionally, because of the high temperatures, resins were kept in temperature controlled storage areas and were conditioned before use to ensure a smooth installation.
The CFRP V-Wrap and concrete enlargement work was completed efficiently and on schedule.