Estimation of the fundamental vibration period of existing RC buildings in Turkey utilizing ambient vibration records

Earthquake design codes generally provide empirical formulae or various approximations for determining fundamental periods of buildings for the evaluation of statically equivalent seismic forces. It is thus important to use realistic periods for the design and performance assessment of existing buildings. This study deals with the evaluation of fundamental vibration periods of reinforced concrete (RC) buildings having a frame-type structural system, and considers the effects of infill walls. The problem is evaluated by utilizing experimental and analytical approaches. A height-dependent relationship to estimate the fundamental period of vibration of Turkish RC moment-resisting frames is derived for a fully elastic condition. Furthermore, a constant parameter is defined to magnify the empirical relationship in order to attain code-specified periods obtained by considering moderate-intensity earthquakes.