In-plane seismic behavior of autoclaved aerated concrete block masonry walls retrofitted with high ductile fiber-reinforced concrete

Abstract

Owing to the absence of confined columns, unreinforced masonry (URM) walls are seismically vulnerable during an earthquake. Hence, this study aims to improve the seismic performances of URM walls built with autoclaved aerated concrete (AAC) blocks through retrofitting techniques using high ductile fiber-reinforced concrete (HDC). Five one-half-scale AAC masonry walls, including a confined wall and four URM walls, were constructed and tested under an in-plane reversed cyclic loading test. The confined wall and one URM wall served as reference specimens, while the remaining walls were upgraded using different retrofitting configurations. The experiment showed the damage progressions, failure modes, and force–displacement diagrams of the test walls, from which the seismic responses could be evaluated based on the shear strength, displacement ductility, energy dissipation, and cyclic stiffness degradation. The test results indicate that the proposed retrofitting techniques could increase the shear strength and energy dissipation of the URM wall, whereas the ductility of the HDC-strip-retrofitted specimen exhibited a negligible improvement. In terms of ultimate displacement, the results indicate that the responses of the URM walls retrofitted using a single-sided HDC layer or HDC strips with built-in steel bars were approximately consistent with those of the confined wall. The proposed formulas were used to estimate the ultimate lateral resistances of the test walls corresponding to different failure modes.