An Evaluation of Design Code Expressions for Estimating in-plane Shear Strength of partiallY Grouted Masonry Walls

Abstract

This paper aims to evaluate the in-plane shear strength expressions of partially grouted masonry (PGM) walls in four international design codes, including masonry design codes of practice in the United States, New Zealand, Canada and Australia. Experimental results of 89 partially grouted masonry walls that displayed shear failure were collected from published research. The shear strengths of the walls in the database were calculated using the different code equations and compared with those from the experimental results. In addition, the parameters that influence the shear strength of the walls, including masonry tensile strength, level of axial compressive stress, wall aspect ratio, and the amount and spacing of vertical and horizontal reinforcement are studied. Both univariate and multivariate regression analysis have been employed to investigate the effect of each parameter on the accuracy of the code shear strength predictions. This study illustrates poor correlation between code predictions and test results, indicating that current codes are unable to predict the shear strength of PGM walls. In some cases the code shear strength predictions are three to four times the experimentally measured shear strength, indicating that modifications are needed as the current provisions are unconservative. An equation is therefore proposed which better estimates the strength of PGM walls.