Damping and natural period evaluation of tall RC buildings using full-scale data in Korea

In recent years, the main usage of reinforced concrete (RC) structures in Korea has shifted from low-rise residential and commercial buildings to high-rise buildings. Because an increasing number of high-rise RC buildings are being built, especially in coastal cities, which are periodically hit by typhoons, wind-induced motion and the corresponding serviceability issues have attracted considerableattention. Natural period and damping ratio are the most important factors fores timating the design wind load and wind-induced response in the design of tall buildings. However, the Korean Building Code (KBC 2009) does not specify empirical formulae for estimating the natural period and damping ratio for wind design, unlike seismic design. In this study, the damping ratio and natural period of existing concrete buildings in Korea are measured and compared to those obtained using the formulae provided in various codes and research works. Furthermore, design formulae for estimating natural frequency and damping ratio for wind design are proposed based on the measured data. For this purpose, ambient vibration measurement is performed for 58 RC buildings with heights of 24.2-305 m.