Effects of curtain wall façade on the dynamic properties of a bulding

Abstract

In recent decades the number of high-rise buildings in Turkey has increased considerably and still growing in number at a high pace. However, there is very limited research on the in-situ behavior of these buildings in Turkey. On the other hand, the emergence of system identification techniques developed especially in the second half the last century provides the possibility of identification of the dynamic properties of buildings through the use of seismic noise recording. The objective of this study is the determination of dynamic parameters of a high-rise building at Maslak, Istanbul prior to and after the installation of the curtain wall façade and interior finishes. In the study, the dynamic characteristics (natural frequencies and mode shapes) were identified using well-known spectral analyses and Frequency Domain Decomposition (FDD) methods. The real-time modal frequencies are estimated by using basic signal processing tools such as baseline correction, band-pass filtering, windowing, FFT, smoothing and decimation. The real-time damping is estimated with half-power bandwidth technique. For this purpose, data validation is done through a series of MATLAB codes developed to perform the main signal processing. The developed MATLAB codes have been tested with the ambient vibration data set recorded from the monitoring structure. Modal properties of the structure have been identified successfully in real-time. Results of the monitoring building test have been compared with finite element model. This study underlines how fundamental and torsional frequencies as well as damping properties vary for the different stages of construction mentioned above.