Experimental study of in-plane shear strength of confined concrete masonry walls with joint reinforcement

Six full-scale confined masonry walls made with multi-perforated concrete units were subjected to reversal cyclic lateral loads. The only variable investigated was the amount of joint reinforcement. All other variables were fixed, the height to length aspect ratio was set to one. The reinforcement, placed in the bed joints every two courses, consisted in small diameter bars with 588 MPa nominal yielding stress. Numerous strain gages were installed on the rebars to monitor deformation and subsequently estimate the lateral strength contributed by the reinforcement. The strength due to the masonry was estimated as the difference between the total lateral strength and the strength attributed to the reinforcement. The results show that the contribution of the reinforcement to the lateral strength increases with the amount of reinforcement to a certain limit and that the contribution of the masonry decreases. The limit is related to the masonry compressive strength. The experiments and results are presented in detail, followed by a discussion and conclusions.