Influence of higher modes of vibration on the behaviour of reinforced concrete shear walls structures

A parametric analytical study was carried out to examine the inelastic seismic response of reinforced concrete shear walls designed according to the provisions of the 2005 National Building Code of Canada (NBCC) and the CSA-A23.3-04 Standard. The studied walls were assumed to be part of 5-, 10-, 15-, 20-, and 25-storey office buildings located in Montreal, QC, and Vancouver, BC. Moderately ductile shear walls qualifying for a ductility-related force modification factor, Rd, of 2.0 were considered for the Montreal site whereas the walls in Vancouver were of the Ductile shear wall category (Rd = 3.5).; Nonlinear time history analyses of the walls were performed under site-specific ground motion ensembles using the Ruaumoko computer program. Two different wall models were used: frame elements with concentrated plastic hinges at their ends and wall elements with fiber discretization of the cross-section.; For both models, the results indicate that the deformation demand of all walls remain below the limits specified in the 2005 NBCC for buildings of the normal importance category. The shear force demand in all structures was found to exceed the values predicted by the capacity design procedures implemented in the CSA-A23.3 Standard. Correction factors are proposed to adequately predict the maximum shear forces in walls for both sites.; A reduced-scale model specimen to study the inelastic seismic response of shear walls by shaking table test in Structural Laboratory at Ecole Polytechnique of Montreal was proposed, designed and verified, as well a modified scaling similitude procedure.