Ahmed Yassin, Mohamed Ezzeldin and Lydell Wiebe
Ahmed Yassin, Ph.D. Candidate, Department of Civil Engineering, McMaster University, 1280 Main St W, Hamilton, ON, Canada yassia1@mcmaster.ca
Mohamed Ezzeldin, Assistant Professor, Department of Civil Engineering, McMaster University, 1280 Main St W, Hamilton, ON, Canada, ezzeldms@mcmaster.ca
Lydell Wiebe, Associate Professor, Department of Civil Engineering, McMaster University, 1280 Main St W, Hamilton, ON, Canada, wiebel@mcmaster.ca
ABSTRACT
In recent years, several studies have been conducted to evaluate the seismic response of controlled rocking reinforced masonry walls with unbonded post-tensioning (PT) tendons. This system is
considered appealing because of the low damage associated with these walls due to their selfcentring capability following a seismic event. However, several challenges associated with posttensioning in masonry construction practice still exist. These include the relatively high prestressing losses and the increased demands at the wall compression toes. Such challenges
clearly demonstrate the importance of considering an alternative source of self-centring. In this respect, this paper reports the results from a series of experimental tests that were conducted on
two Energy Dissipation-Controlled Rocking Masonry Walls (ED-CRMWs) to evaluate the capability of the system to self-centre through vertical gravity loads only, without the use of PT tendons. Both walls were half-scale concrete masonry blocks and fully grouted, with identical dimensions and amounts of energy dissipation. However, one wall was without any confinement,
while the other wall had end confined boundary elements using closed ties. The two walls were tested under quasi-static loading with fully-reversed cycles up to failure. The current study focuses first on the ability of the system to dissipate energy while preserving the advantage of localized damage. The study then explores the influence of toe confinement using boundary elements in enhancing the seismic response of ED-CRMWs. The experimental results are discussed with respect to the observed damage, residual drifts, and displacement ductility capacities.
KEYWORDS: self-centering, controlled rocking, experimental testing, energy dissipation
