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Comparison of Safety Levels of Reinforced Masonry and Concrete Walls Using Reliability Analysis
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- Author / Creator
- Casaverde Lopez, Oswald
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The strength reduction factors in the Canadian masonry design standard were last calibrated in the 1980s. The factors were last updated (2004) based on reliability studies performed on reinforced-concrete structures, but no masonry-specific reliability analyses were conducted to support this change. Uncertainty remains as to whether the current masonry standard leads to unsafe or overly conservative designs.
Modern masonry construction is comprised, in its majority, of walls (shear walls and out-of-plane walls). This study investigates the reliability levels for non-slender reinforced masonry walls under combined axial load and out-of-plane bending, and compares the results with reliability analyses performed in walls made of reinforced concrete. Comparing walls made of two materials under similar loads will allow an objective analysis of the reliability levels in the current masonry standard.
The results show reliability indices for masonry and concrete walls are influenced by the amount of reinforcement in the walls and the compressive strength of the materials. Overall, for the same compressive strength and reinforcement ratio, masonry and concrete walls had similar reliability indices, although masonry showed higher sensitivity to changes in these parameters. The reliability of singly reinforced walls of either material was not significantly sensitive to changes in the compressive strength and reinforcement ratio. In contrast, doubly reinforced walls exhibited sensitivity to these parameters. Doubly reinforced masonry walls were more sensitive to changes in compressive strength and reinforcement ratios than doubly reinforced concrete walls. Doubly reinforced walls of either material generally had higher reliability values than singly reinforced walls.
Overall, the study shows that it is reasonable to assume similar reliability values for masonry and concrete walls with comparable compressive strengths and reinforcement ratios. However, enhanced supervision control is required for masonry construction because their reliability is very sensitive to workmanship factors. Reducing variability through enhanced supervision control of masonry would lead to increase in safety and, consequently, an increase in the strength reduction factor. This, in turn, results in a higher design capacity of structural masonry.
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- Subjects / Keywords
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- Graduation date
- Fall 2023
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.