Performance evaluation of a seismic strengthening applied on a masonry school building by dynamic analyses

Abstract

With its unreinforced masonry structural system, Münevver Şefik Fergar Primary School has been analyzed and retrofitted by the Istanbul Project Coordination Unit, IPKB in Istanbul. The applied strengthening is mainly composed of the addition of reinforced concrete layers to the masonry walls by shotcreting. This study is performed to monitor the variation of the dynamic properties of the building through the constructional works and evaluate the effects of the performed retrofitting. For this aim, six sets of operational modal analysis type dynamic identification, starting from the original building and ending with the retrofitted building, were performed to extract the dynamic properties of the building. To discuss the effectiveness of retrofitting efficiently, numerical analyses have also been conducted. The original and retrofitted form of the building has been modeled by finite element modeling technique and Eigenvalue analyses were performed to obtain the dynamic properties of the building numerically for both phases. The comparison of the dynamic characteristics of the original and retrofitted building enabled the assessment of the efficiency of the applied seismic strengthening. Moreover, the experimentally and numerically obtained results were compared. It is seen that, while both experimental and numerical results proved the effectiveness of the performed retrofitting to increase the dominant frequencies of the building, the difference in their quantity was worth noting and should be accounted for seismic analysis of similar structures.