Absorbers of Seismic Energy for Damaged Masonary Structures

Abstract

In the present paper problem of damage of masonry structures due to earthquake is considered. It is known that masonry structures are very sensitive to earth shaking. Built from the bricks and bond by mortar, they cannot transmit large tensile stresses. Due to small earthquake of the magnitude 4–5 of the Richter scale those structures are usually damaged. Numerical calculation using FEM is applied on typical example of two store building ( Fig. 3). Also in the paper procedure of retrofit of damaged structures, using system DC 90, is shown. Results of laboratory testing of dampers of the system DC 90 due to dynamic loading with frequency 1–10 Hz are presented. Results are obtained in three institutes: IZIIS (Skopje), VTI (Belgrade) and IMS (Belgrade). Obtained results show high performances of dampers, which after embedment increase stiffness and ductility of structures up to 30% (Fig. 2). Besides that, results of model testing, obtained on vibro-platform for different type of masonry structures, which have been used in the areas of tectonic faults, are shown. Special attention have been made to testing in situ due to ambient vibrations (wind, earth shaking) and induced vibrations due to eccentric mass (Fig. 1). This testing was performed on damaged structures before and after embedment of dampers. Measurements are performed in Kolubara region by institute IZIIS and IMS. All investigations show high performances of embedded dampers (for which word prize was obtained on international exhibitions of patents and new technologies, Brussels Eureka 97). In the present paper process and methodology of transfer of technology for application of the system for large area heated by earthquakes is specially outlined. On examples of large number of objects reconstructed using system DC 90 in Kolubara region (Serbia), Algeria and Iran all advantages of the system DC 90 will be presented.