Seismic Strengthening of Unreinforced Masonry Structures Using Eco-friendly Ductile Cementitious Composite Repair Material
Date
2018-02-02
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Abstract
Masonry has been used to construct different kinds of structures for thousands of years. Unreinforced masonry structures suffer from low tensile strength and low ductility due to the absence of steel. Therefore, during an earthquake unreinforced masonry structures are more prone to damage than reinforced ones. In addition, many masonry structures are, or become, unsafe due to weathering, poor maintenance and inefficient structural systems for resisting lateral load. In masonry structures, the walls are usually the main structural elements expected to resist the lateral forces and to dissipate the earthquake input energy. Existing masonry structures in seismic areas that do not comply with the new earthquake building regulations typically need to be strengthened and retrofitted to increase their survivability during an earthquake.
The intent of the research described in this thesis was to find a simple, eco-friendly, sustainable way of strengthening existing unreinforced masonry structures in areas of Canada where earthquakes are known to happen, such as schools and low-rise office complexes in British Columbia (BC). The experimental study investigated the effects of bonding Eco-friendly Ductile Cementitious Composite (EDCC) repair material to the surfaces of plain, concrete-block masonry walls (not reinforced with steel) on the structural behaviour of those walls.
The research was part of a collaborative study between researchers at the Universities of British Columbia, Calgary and Manitoba. The study involved development of the EDCC repair material and a wide range of material and structural tests. This research was on the structural testing, including quasi-static, free vibration and shake table tests. In total, thirty large scale specimens representing masonry walls in schools in BC were tested during my part of the research. Of the thirty specimens, fifteen specimens have been tested under free vibration and quasi-static loading conditions. The shake table at the University of Calgary was used to simulate ground motions for testing the remaining specimens, including eleven straight walls, two U-shaped specimens, and two L-shaped specimens.
This experimental study has provided new results and findings in the field of structural engineering to improve the quality of unreinforced masonry structures in Canada and has also opened up a new field with regard to the application of binders with much reduced Portland cement to decrease carbon dioxide emissions due to the production of Portland cement.
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Keywords
EDCC, Seismic Strengthening, Unreinforced Masonry, Shake Table, Quasi-static, Free Vibration
Citation
Kaheh, P. (2018). Seismic Strengthening of Unreinforced Masonry Structures Using Eco-friendly Ductile Cementitious Composite Repair Material (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/5470