In-plane shear strength equation for fully grouted reinforced masonry shear walls

摘要

The flexural behavior of reinforced masonry (RM) shear walls is well defined and follows the simple flexural theory of reinforced concrete structures based on plane-section assumption. Conversely, the shear behavior of RM shear walls in the plastic hinge region is more complex due to the lack of comprehensive models that quantifies the interaction of the various mechanisms that contribute to the shear capacity. This paper aims to provide a comprehensive equation for predicting the in-plane shear strength, V-n, of RM shear walls. The proposed equation was verified against the results of 68 full-scale fully grouted RM shear walls from six sources in the literature tested under cyclic lateral excitations. The main variables considered in the experimental data were: the level of axial compressive stress, shear span to depth ratio, reinforcement ratio, anchorage end detail, and the spacing of reinforcement. Then, statistical analysis was performed to evaluate the precision of the proposed equation against ten widely-used equations, including the design equations given in the Canadian Standards Association CSA S304-14 (2014), the US Masonry Standards Joint Committee MSJC (2013), and the Standards Association of New Zealand NZS 4230:2004. The results of the statistical analysis show that the proposed equation provides a precise and sufficiently conservative prediction of the shear strength (V-n). The proposed equation conservatively accounts for the contribution of masonry and axial load (Vm+p), and horizontal reinforcement (V-s) to the shear resistance (V-n) while considering the influence of the level of ductility demand. It also considers the vertical reinforcement contribution to the in-plane shear strength.