No abstract

Natural frequencies are important dynamic characters of building structures and can be determined by analytical or experimental methods. Over time, under the effect of loads, environment, random factors..., the characteristics of the building structure are changed, leading to a change in the dynamic characteristics. The paper presents how to determine the natural frequencies of the building structures by the frequency domain decomposition (FDD) method. This method belongs to the group of Operational Modal Analysis (OMA) method, which only uses vibration measurement data of structures to determine the natural frequencies without knowing forces acting on the structure.