Evaluations of the dynamic properties for a residential tall building in Korea

The construction of tall buildings can be regarded as one of the most complex and expensive projects. It thus seems important to design the structure of a tall building in terms of cost effectiveness to ensure the success of a construction project. The structural cost of a tall building is generally determined by lateral wind loads and responses. Also, lateral wind loads and responses generally depend on dynamic properties, such as natural frequencies and damping ratios. Although the computational method has been remarkably well developed, there are still considerable uncertainties in the analysis of natural frequencies. Moreover, damping ratios tend to be rather subjectively assumed in response analysis, although the analysis results might be quite distorted due to the improper assumption of damping ratios. Hence, as an effort to investigate actual dynamic properties of tall buildings, a full-scale measurement of a tall residential building was performed when the typhoon, Man-yi, hit Korea in 2007. The natural frequencies of the building were identified with the measured acceleration responses and compared with the FE modal analysis results. Also, the measured damping ratios were compared with the results of the damping predictor proposed by the Architectural Institute of Japan (AIJ). Based on these comparisons, a proper evaluation procedure of dynamic properties was proposed for practical engineering works of tall building design.