SEISMIC RISK AND LOSS ASSESSMENT OF REINFORCED CONCRETE FRAME STRUCTURES STRENGTHENED BY THE ADDITION OF MASONRY INFILL WALLS

This study addresses the behaviour of bare plane RC frames and RC frames strengthened by the addition of masonry infill in combination with the connection of infill and frame elements for earthquake action. The main objective was to explore the possibilities of using infill walls in RC frames as a strengthening method, observing the in-plane cyclic responses obtained through experimental tests on specific specimens. The experimental part of the study was carried out on 10 single-bay, single-storey specimens of ductile and non-ductile RC frames strengthened with masonry infill (hollow clay block and solid clay brick units) and on 7 associated reference specimens used to evaluate the strengthening of the infill and the quality of the mutual connection between the infill and the frame. The frame specimens are built to a scale of 1:2.5 for ductile and 1:2 for non-ductile frames and tested under constant vertical and horizontal cyclic loading. The test specimens can be grouped according to the type of infill (hollow clay block and solid clay brick units ), the type of RC frame (ductile and non-ductile), and the type of connection between the infill and the frame. The same preliminary simplified calibration with non-linear macro models in OpenSees was performed for all test specimens for which satisfactory responses to cyclic responses were obtained compared to the experiments. The same models were used in the numerical case study for predicting the dynamic response to the application to a case study building through Incremental Dynamic Analysis (IDA), where IDA curves, fragility functions, vulnerability and loss curves, and risk measures such as Expected Annual Loss (EAL) and Annual Average Collapse Probability (AACP) were created separately for each type of strengthening to evaluate the efficiency of a particular strengthening compared to reference models.