W. G. CURTIN Curtins, Consulting Engineers

It is suggested that the increase in flexural strength, perpendicular to the bed joints, fkxn, is due to their torsional or shear resistance. Simplified equations are developed to predict the variation of orthogonal ratio, u, with fkip parallel to the bed joints. The predictions show good correlation with experimental results. The critical importance of developing understanding of this phenomenon is briefly demonstrated in geometric sections and in the progress of prestressed masonry. Such development needs detailed laboratory investigation.