A. Yassin1, M. Ezzeldin1 and L. Wiebe1
1)  Dept. of Civil Engineering, McMaster University, Canada
{yassia1, ezzeldms, wiebel}@ mcmaster.ca

Keywords: Controlled Rocking, Masonry Walls, Self-Centering, Unbonded Post-tensioning

Abstract. In recent years, several studies have been conducted on the in-plane flexural response of controlled rocking reinforced masonry walls that use unbonded post-tensioning. This system has attracted attention not only because it can provide a high deformation capacity, but also because the unbonded post-tensioning can re-center the wall after loading, minimizing or eliminating its residual drifts. As such, predicting the force-displacement response of unbonded post-tensioned masonry walls typically requires analytical procedures that account not only for uplift, but also for local deformations near the compression toe. In this respect, the current study proposes and validates an analytical procedure to predict the forcedisplacement response of unbonded post-tensioned masonry walls. The validation of this procedure is based on four previously tested walls with different configurations and aspect ratios. Within this procedure, an enhanced equation for the height of compression deformation is proposed, so as to consider the variation in the wall axial stress levels as the system deforms. In addition, this procedure uses a material model that accounts for the influence of the masonry confinement on enhancing the strain capacity of the compressed zone. The proposed procedure also considers the attachment of any energy dissipation sources within the wall. The results in the current study demonstrate that the proposed procedure can predict most relevant characteristics of the cyclic response envelope, including the wall lateral strength, stiffness, and strength degradation at different drift demands.