Experimental investigation of strengthening of masonry-infilled RC frames using prefabricated engineered cementitious composite panels

Abstract

Cement-based composite materials such as engineered cementitious composites (ECCs) are appropriate for retrofitting buildings because of their high tensile strength and strain. This research evaluated the lateral behavior of strengthened masonry-infilled reinforced concrete (RC) frames reinforced with prefabricated engineered cementitious composite (PECC) panels. The goals of the proposed technique were to increase the energy absorption capacity and the lateral capacity of infilled RC frames and protect the stability of the masonry infills after cracking and brittle failure in the out-of-plane direction, which can contribute to the seismic vulnerability of a structure. The mechanical characteristics of the ECC materials, such as the tensile strength and strain and multiple cracks, were first determined. Then, nine diagonal compression tests were done on masonry panels strengthened with PECC panels. In these tests, two types of connection were compared and the best one was selected. Next, an existing one-story RC moment frame with one bay was scaled down for testing under lateral cyclic loading. The results indicated that the strength, deformation, stiffness, and energy absorption of the RC frames increased considerably. Additionally, the effects of the precast panel thickness, performance of the connections, and type of damage sustained were compared between the different types of tests. Overall, the PECC panels connected to the infill wall with the proposed connections improved the lateral behavior of the system in the in-plane direction and markedly mitigated the risk of collapse by confining the masonry infill wall.