M. E. PHIPPS and C. K. J. LAU
University of Manchester Institute of Science and Technology

Masonry walls and columns are increasingly constructed with built up geometric cross sections (that is, not solid and not necessarily rectangular). Normal design methods for vertical loads really only deal with solid rectangular sections and modifications to the effective thickness to allow for cavities and piers are insufficient to cater for geometric sections in general. A method to work out the strength of geometric walls and columns is presented based on a parabolic nonlinear compressive stress strain relationship and the masonry is assumed to have zero tensile strength. Axial load plus both uniaxial and biaxial bending are considered along with the effects of slenderness. Equal eccentricity is assumed at the top and base of the wall. Test results from 14 concrete block columns of different geometric cross section ere also presented and the results are compared with the theoretical predictions.