1 Structural and Construction Feature of the Hong Kong International Financial Center Phase II

The 88-storey International Financial Centre Tower 2 (IFC2) is no doubt the most eye-catching skyscraper in Hong Kong that erects on the south bank of the Victoria Harbour. The building had been completed and opened for occupation in August 2003. The IFC2 or Two IFC, with an averaged floor area of about 2300 sq meter, is a composite structure comprising of a RC inner core and an external steel frame supported by 8 mega-columns. In order to stiffen the building against strong wind during typhoon session which is about the summer time of Hong Kong, the structure of the building is strengthened by 4 sets of outrigger systems at a separating interval of about 25 storeys. And of which, 3 set of outrigger systems are provided with special joining devices which can cater for the differential shortening which may occurs between the inner reinforced concrete core and other outer structural steel elements. To support this gigantic building, a 62m diameter cofferdam lined on the side by 1.5m thick diaphragm wall had been built before the foundation was constructed. Two IFC was then founded on a 6.5m thick RC raft seated on bedrock 35m below ground. In addition, the development also includes a 16000 sq meter 6-level podium for retail purposes and a 5-level basement for car parking. The construction of the Two IFC is indeed a splendorous job for engineers and contractors. This paper outlines the structural and construction features of the two IFC. The top-down construction technique for basement construction and the installation of the outrigger system by a retro-installed approach are discussed as well.