Cyclic response of reinforced concrete frames partially infilled with relatively weak masonry wall

Partially infilled reinforced concrete (RC) frames have experienced significant damage during past earthquakes. Due to the partial confinement of columns in these structures, the shear force demand increases significantly, resulting in a brittle failure. This study investigated the efficiency of the strong frame-weak infill wall design concept to avoid the brittle failure mode of captive columns. For this purpose, two large-scale partially infilled RC frames with similar material properties and geometry but with different seismic detailing were constructed and subjected to a quasi-static cyclic loading. The obtained results from the conducted experiment were compared with two bare frames with similar detailing and geometry. It was observed that the partially infilled frames had up to 49.6% larger ultimate load than bare frames. Besides, at a 3% drift ratio, the cumulative energy dissipation of partially infilled frames was up to 180% more than bare frames. However, the stiffness degradation rate of the partially infilled frames was higher than the bare frames, particularly at drift ratios less than 1%. Besides, at larger drift ratios (i.e., around 3%), the infill walls contributed to partially infilled frames' lateral strength and increased it up to 60% compared with the bare frames.