The ductility of structural walls

The behaviour of four approximately 1/4 full size reinforced concrete structural wall models, subjected to cyclic lateral shear load and variable axial compression, is reported. The primary aim of the study was to investigate the mechanism of out of plane instability and the adequacy of existing code provisions with respect to the confinement of critical parts of the flexural compression zones of wall sections that may be subjected during an earthquake to large inelastic displacements. While all units exhibited good energy dissipation properties, failure in the majority of cases occurred suddenly when concrete compression strains resulting from large ductility demands became excessive in the unconfined regions of the wall section. Failure by out of plane buckling was found to occur at a relatively small lateral load, after the buckled region has been subjected in a proceeding cycle to very large inelastic tensile strains. Recommendations are made for improved arrangement of the confining hoop reinforcement in the end regions of wall sections.