Seismic performance of four-storey masonry infilled reinforced concrete frame building

Masonry infilled reinforced concrete frames are a structural system commonly used for low-to-mid-rise buildings. Generally, this type of structure is modelled as an open frame neglecting the strength and stiffness contribution of the masonry infilled panel. In order to describe realistic behaviour under lateral loading, this paper evaluates the seismic performance of the building by modelling the contribution of masonry as a compression strut acting diagonally in the panel. The non-linear static procedure is employed by subjecting the building to pushover loads. The performance of the building is then analysed based on the obtained capacity curve. Seismic performance is assessed in terms of building fragility which is the conditional probability of exceeding certain damage state for a given ground shaking intensity. Fragility functions eventually are expressed as series of log-normal curves of both the open and masonry infilled reinforced concrete frame. Based on this study, the infilled frame can resist a maximum load of 20.3x103 kN, while the open frame is only able to withstand a maximum load of 15.2x103 kN. From the fragility curve, it can be concluded that the probability of the infilled frame to reach a certain damage state is lower than that of the open frame