Seismic analysis of an 18th-century eastern orthodox church with RC seismic retrofits

Romania is a seismic prone country, and it has experienced multiple strong earthquakes. Orthodox churches were damaged during such earthquakes. The Saints Archangels Michael and Gabriel Church is an aisleless cruciform with a drum in the centre, showing a typical Brâncovenesc style that flourished in Romania in the 18th century. It was built in Craiova County in the early 18th century. After the 1977 Vrancea earthquake, it was extensively retrofitted with ring beams, ties and columns built of reinforced concrete (RC). In this paper, the performance of the church was evaluated by nonlinear static and nonlinear dynamic analyses. A numerical model was calibrated, based on a dynamic identification test performed on the real structure. The analyses showed the positive contributions of the RC seismic retrofits, as it increased the capacity and stiffness of the structure by providing confining effects and vertical supports. Another model was discretised, representing the state before the RC seismic retrofits. This model presented the damage patterns observed in the real structure during the 1977 Vrancea earthquake. Few studies have been carried out on the seismic assessment of orthodox churches based on detailed nonlinear analysis of a calibrated model with a focus on the seismic retrofits applied to the real structure. This paper provides insights on the seismic performance of orthodox churches with a drum as well as the numerical analysis of such churches.