2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Dr. Lotfi Guizani, École de technologie supérieure
Dr. Ahmad Abo-El-Ezz, Geological Survey of Canada, Natural Resources Canada
Mr. Jonathan Touraille, École de technologie supérieure
Mr. Éric Boldireff, École de technologie supérieure
Mr. Pascal Moretti, École de technologie supérieure
Eastern Canada has a large stock of old brick or stone URM buildings with architectural heritage value. To reduce the potential earthquake induced damage to those URM load-bearing walls structures, architects and engineers are faced with the challenge of evaluating their lateral resistance and seismic performance and selecting efficient rehabilitation and strengthening strategies. Evaluation of the lateral resistance of URM walls is also key information in damage prediction for seismic risk studies. However, there is limited reported information regarding the mechanical properties of those URM walls, leading to difficulty in providing a reliable prediction of their seismic resistance. These buildings are made of multi-leaf walls, made of two or three layers of materials of different qualities and properties (stone, rubble stone, brick, tiles). The cohesion of the masonry assemblies is typically compromised by the degradation of the mortar, resulting in insufficient resistance to earthquakes induced in plane and out of plane loads. Reliable evaluation of seismic resistance of URM walls requires knowledge of their composition and their geometric properties but most importantly their mechanical material properties. Moreover, they require reliable and validated simple analytical models to calculate the resistance of URM walls. In collaboration with the architectural firm EVOQ, an experimental program was initiated to validate these models from the behaviour of typical URM walls under axial compression, shear loading and cyclic loading. The experimental program included three distinct phases: (1) Characterization of the mechanical properties of the masonry and its constituent materials: manufactured moulded brick typically used as replicas of traditional masonry, limestone blocks and cement-lime mortar used to match the mechanical properties of the original traditional cement-lime mortar. (2) Evaluation of the diagonal shear strength of brick or stone masonry wall specimens. (3) Evaluation of the lateral force-deformation behaviour of the representative wall specimens under cyclic loading to capture the complex dynamic response and nonlinear behaviour of the masonry.
The obtained results are used to validate equations presented in standards, such as ASCE 41-13 to predict lateral resistance of masonry walls and to develop predictive relations between the constituent material mechanical properties and the masonry mechanical properties. These are particularly useful for seismic vulnerability studies of traditional unreinforced masonry buildings, as well as in the evaluation of seismic resistance and the decision-making process of selecting efficient upgrading solutions of heritage masonry buildings.