Matthew East, Mohamed Ezzeldin and Lydell Wiebe
Matthew East, PhD Candidate, Department of Civil Engineering, McMaster University, Hamilton, ON, L8S 4L7, Canada, eastma@mcmaster.ca
Mohamed Ezzeldin, Assistant Professor, Department of Civil Engineering, McMaster University, Hamilton, ON, L8S 4L7, Canada, ezzeldms@mcmaster.ca
Lydell Wiebe, Associate Professor, Department of Civil Engineering, McMaster University, Hamilton, ON, L8S 4L7, Canada, wiebel@mcmaster.ca
ABSTRACT
Controlled rocking systems have been used in numerous structures around the world as a seismic force resisting system. In a controlled rocking wall system, the wall is allowed to uplift from the
foundation during seismic events, reducing its lateral stiffness and minimizing the seismic force demands. This rocking response is controlled using post-tensioning and/or supplemental energy dissipation. In this way, controlled rocking walls are designed to have less damage than conventional systems and to have negligible residual deformations. Promising strides have been taken to apply the concept of controlled rocking systems to masonry walls; however, several issues have been encountered due to the low strength and brittle nature of the masonry material in compression. In addition, there are many challenges with the numerical modeling of controlled rocking masonry walls (CRMWs) due to the variability of the material and the anisotropic nature
of the systems they form. The current paper develops and validates a numerical model to capture the performance of CRMWs. The wall arrangement considered herein omits post-tensioning and maintains the footprint of a conventional reinforced masonry shear wall, while also providing enough space to install replaceable energy dissipation devices to address the low inherent damping of CRMWs. First, the model has been validated based on experimental tests in previous studies of other walls and energy dissipation components. The model is then used to evaluate a damage index, adapted from damage modeling of reinforced concrete components. Finally, the validated model is used to analyze a 2-storey CRMW in order to evaluate the amount of damage compared to that
of a conventional reinforced masonry shear wall.
KEYWORDS: seismic design, controlled rocking, reinforced masonry, shear walls, numericalmodelling
