Assessment of the seismic vulnerability of an existing historical structure is quite a challenging task compared with the structural analysis of a new structure. However, the preservation of heritage architecture is a major concern around the world. The conservation and valuation of cultural heritage has lately been considered a strategic importance in public policy. This importance is related to not only to cultural but also economic issues such as the tourist industry, which is increasingly important over the years. A great deal of the heritage architecture consists of masonry structures, not only in Japan but also all over the world. Masonry is esteemed as one of the first construction techniques, therefore it can be widely seen in historic sites.
In this paper, seismic evaluation of the Handa Akarenga Building, which was constructed more than 100 years ago, was carried out. Dynamic identification of the structure was performed, using the results of Microtremor measurements, and fundamental frequencies of the structure were estimated to be about 6.4 Hz and 8.8 Hz in the N-S and the E-W directions, respectively. Based on the random decrement technique, the damping ratio was estimated to be around 1.93%.
Seismic capacity evaluation according to Japanese building code was conducted in order to evaluate the need for retrofitting the structure. Moreover, material tests were carried out to identify Young’s modulus, compressive, tensile and shear strength of the brick and mortar used. A 3-D model of the structure was also created in order to carry out non-linear static (pushover) analysis and evaluate the vulnerability of the structure. Using Capacity Spectrum Method, the ‘Performance Point’ of the structure has a spectral displacement value of 10 cm and a spectral acceleration value of 0.50g.