In-Plane and Out-of-Plane Behavior of Masonry-Infilled RC Frames Strengthened with Fabric-Reinforced Cementitious Matrix

In the present experimental study, six single-story, single-bay half-scale masonry-infilled reinforced concrete (RC) frames were tested to evaluate the performance of fabric-reinforced cementitious matrix (FRCM) strengthening under bidirectional loading. Five of these infilled RC frames were strengthened using different configurations, by varying the mode of fabric application, the presence of anchors, and the orientation of the fabric. Two methods of fabric application were employed in the present study: direct application and sandwich application. A unique loading protocol was used for the bidirectional loading of specimens which consisted of successive application of slow cyclic drifts for in-plane loading and shake table–generated ground motion for out-of-plane loading. The strengthened infills safely withstood story drifts of over 2.20%, preserving structural integrity without jeopardizing out-of-plane stability. The direct mode of fabric application exhibited superior performance with better bond characteristics and stress redistribution between the frame and infills. The mechanical anchors were effective in limiting the separation of infills from the frame, resulting in an enhanced bidirectional response. Orthogonal orientation of the fabric with respect to bed joints was more effective than oblique orientation.