Experimental study on in-plane seismic behavior of unreinforced and damaged unreinforced masonry walls retrofitted with vertical concrete ties and bed rebar with and without shotcrete

摘要

This article presents an experimental investigation aimed at evaluating the influence of vertical concrete ties and bed rebar on the retrofitting and in-plane behavior of unreinforced masonry (URM) and damaged unreinforced masonry (DURM) walls, with and without shotcrete. Full-scale specimens were tested under in-plane cyclic lateral and vertical loading, with the protocol repeated four times under the same support conditions. One specimen was loaded as a reference, then the damaged specimen was retrofitted with vertical concrete ties and bed rebar on one side and tested. The final specimen was retrofitted with vertical concrete ties and bed rebar and tested. The study's findings indicate that retrofitting masonry walls with the proposed techniques can significantly improve their behavior. Retrofitting the damaged masonry wall with vertical ties and bed rebar altered the failure mode at the location of the vertical concrete ties from rocking to bed joint shear sliding. Application of shotcrete on the damaged specimen created a completely stiff panel that prevented crack formation and increased the wall's resistance capacity and energy dissipation. Additionally, retrofitting the masonry wall with bed rebar and vertical concrete ties changed the failure mode from rocking to bed joint shear sliding.