The response of concrete masonry with widely-spaced reinforcement to in-plane shear: state-of-the-art and research needs

Abstract

Wide-spaced partially grouted reinforced masonry has vertical reinforcement placed at intervals of more than 800 mm. This type of masonry can fail in additional modes compared to plain unreinforced masonry (URM) and reinforced masonry where the vertical reinforcement is placed at spacings of 800 mm or less when subject to in-plane shear. We review what is known about the in-plane shear failure of concrete block masonry and the factors that affect the mode of failure. We explain the additional failure mode that wide-spaced reinforcement introduces and review what little is known about that failure and how to predict it. Current codes of practice severely overestimate the in-plane shear strength of this type of masonry. We show that some progress has been made in gaining an understanding of the behaviour of wide-spaced reinforced masonry and assess that the effects of axial stress, panel and wall aspect ratio, panel-to-frame stiffness and openings need to be examined in more detail in order for design rules to be developed.