Amir Rezaeivahdati1, Lisa R. Feldman2
1) M.Sc. Student, University of Saskatchewan, Dept. of Civil, Geological, and Environmental Engineering
57 Campus Drive, Saskatoon, SK, S7N 5A9, Canada
e-mail: amr277@mail.usask.ca
2) Associate Professor and Director of the Saskatchewan Centre for Masonry Design, University of
Saskatchewan, Dept. of Civil, Geological, and Environmental Engineering
57 Campus Drive, Saskatoon, SK, S7N 5A9, Canada
lisa.feldman@usask.ca
Keywords: Unreinforced masonry, concrete block walls, empirical design, rational design,
out-of-plane loading, Monte Carlo simulation
Abstract. CSA S304-14 – Design of Masonry Structures includes both empirical and rational design provisions for unreinforced, vertically spanning, non-loadbearing, exterior concrete block walls subject to wind. Counter-intuitively, there are cases when the empirical provisions produce less conservative results than when the same wall is designed in accordance with the rational provisions.
A review of the relevant literature suggests that influencing parameters include: mortar type, support conditions, wall slenderness ratio, and load application method. An experimental program was conducted to provide additional data as related to: mortar type, realistic support conditions, and slenderness ratios. A reliability analysis was performed using a Monte Carlo simulation to determine the resulting reliability index of unreinforced masonry walls subjected to out-of-plane loading for each of the parameters under investigation. The results suggest that the empirical method should not be permitted for walls with slenderness ratios higher than 12. Additionally, a reduction of the limitation provided for the 1-in-50 year hourly wind pressure used in the empirical method from 0.55 kPa to 0.29 kPa should be considered for walls with slenderness ratios up to 12 in buildings with significant openings. Additional data related to select input parameters would bolster the existing test database and improve the accuracy of the statistics necessary for the analysis.