Experimental assessment of the in-plane lateral capacity of autoclaved aerated concrete (AAC) masonry walls with flat-truss bed-joint reinforcement

• In-plane cyclic tests of AAC masonry walls with bed-joint (BJR) reinforcement only.
• Flat-truss steel BJR increases AAC masonry vertical compressive strength.
• BJR increases flexural and shear drift capacity in AAC masonry.
• A small amount of reinforcement provides a significant increase in shear strength.
• BJR controls cracking and shifts damage limit states towards higher drifts.

Experimental campaigns carried out in the past showed that the presence of truss bed-joint reinforcement provides a general improvement to the performance of masonry panels subjected to horizontal actions. The truss-like elements are effective in improving resistance and reducing damage and, therefore, they enhance the displacement capacity. The experimental tests available in the literature, performed on prototypes in different scale or in small number compared to the possible combinations of slenderness, axial load and boundary conditions, hardly allow drawing quantitative conclusions on the real benefit of the presence of horizontal reinforcement to the performance improvement for a specific masonry type. The experimental campaign presented in this paper includes a set of in-plane cyclic tests on Autoclaved Aerated Concrete (AAC) masonry panels with thin horizontal and vertical joints filled with thin layer mortar, made both in unreinforced and bed-joint reinforced masonry with flat-truss bed-joint reinforcement. The direct comparison of the results, along with specific tests performed on wallettes made with the two different construction technologies, allows the assessment of the effectiveness of the horizontal reinforcement in enhancing the in-plane seismic performance of AAC masonry.