Innovative instrumentation to study the behaviour of a high-rise building

Abstract

Standing at 280 m, the 66-storey Republic Plaza building is one of the tallest buildings in Singapore. The structural system of the building comprises a reinforced concrete core wall and a structural steel frame. The steel tube columns, filled with concrete, form an external ring, while the horizontal steel frame systems simply supported at the core wall support a composite slab at each floor. A large number of stress and strain gauges were embedded inside the core wall and the concrete filled tube (CFT) columns. At selected floors, strain gauges were mounted in the steel beams. During construction, the trends observed in stress and strain measurements of the core wall and the CFT columns are generally consistent with the increasing dead loads, while the tends in strain data for the floor beams are more complex. An ambient vibration survey (AVS) was conducted after the completion of the structure. From the AVS measurements of dynamic lateral response, natural frequencies and mode shapes for lower lateral and torsional modes have been obtained. Results of the finite element models for the core wall/steel framing system agree reasonably well with the measured translational fundamental frequencies. However, without a high level of refinement, the finite element models cannot reflect the torsional behaviour. There is no evidence that the curtain wall system affects stiffness or damping properties of the structure at low excitation levels.