Ahmed Ahmed, George Iskander, Mihailo Bogoslavov, Andrea Isfeld and Nigel Shrive,
Ahmed Ahmed, PhD student, Department of Civil Engineering, University of Calgary, 2500 University Dr NW, Calgary, AB, Canada, ahmed.ahmed1@ucalgary.ca
George Iskander, PhD student, Department of Civil Engineering, University of Calgary, 2500 University Dr NW, Calgary, AB, Canada, george.iskander@ucalgary.ca
Mihailo Bogoslavov, MSc student, Department of Civil Engineering, University of Calgary, 2500 University Dr NW, Calgary, AB, Canada, mihailo.bogoslavo1@ucalgary.ca
Andrea Isfeld, Research Associate, Department of Civil Engineering, Newcastle University, University Dr, Callaghan NSW 2308, Australia, andrea.isfeld@newcastle.edu.au
Nigel Shrive, Professor, Department of Civil Engineering, University of Calgary, 2500 University Dr NW, Calgary, AB, Canada, ngshrive@ucalgary.ca
ABSTRACT
Slender concrete masonry walls can fail through compression, flexure or buckling. Previous finite element modelling showed the governing mode of failure of axially loaded walls depends on both
slenderness and load eccentricity. However, exterior walls will be subjected to lateral as well as axial loads. Therefore, the effect of lateral pressure on the failure mode of unreinforced, ungrouted slender concrete masonry walls was investigated. Finite element models of walls with and without lateral loads representing average Canadian wind pressures were compared to assess the influence of lateral load on wall capacity and failure mode. Such models were analyzed across a broad range of axial load eccentricities and slenderness ratios. The effect of the distribution of the lateral pressure (triangular vs. rectangular) was also investigated. Models loaded with lateral pressures corresponding to maximum Canadian wind pressures were also analyzed but over a smaller range of axial load eccentricities and slenderness ratios. Certain walls, which the Canadian Standard for the Design of Masonry Structures, CSA S304-14 deems slender, failed in compression when loaded at a low axial load eccentricity, despite the applied lateral pressure. Hence, it is proposed that CSA S304 should classify slender walls by failure mode which would greatly reduce the current inaccuracy in the design of slender walls loaded at low axial load eccentricities.
KEYWORDS: slender walls, out-of-plane bending, mode of failure
