24. Inelastic Shear Response of RC Walls: A Challenge in Performance Based Design and Assessment

The large inelastic shear modification factors proposed in Eurocode for ductile RC walls have been verified and modified. Due to this large amplification, which has, in the past, been ignored, and still is, by many designers, RC walls with insufficient shear resistance have been designed and built. In order to study the seismic vulnerability of such walls, a model was proposed, which takes into account both inelastic shear behaviour and inelastic shear-flexural interaction. It is based on the multiple-vertical-line-element macro model. An additional shear spring, which accounts for aggregate interlock , dowel action and horizontal reinforcement resistance, is incorporated into each of the vertical springs. The model successfully simulated the response of a five-storey coupled wall that was tested on the shaking table under bi-axial excitation . The shear resisting mechanisms within the cracks were adequately modelled up until the tension shear failure of both piers.