Reliability Assessment for Loadbearing Concrete Masonry Walls Subjected to Gravity and Lateral Loads

Abstract

The current Canadian standard for masonry structures design (CSA S304-14) is based on a Limit-State Design (LSD) philosophy, incorporating masonry-specific material strength reduction factors initially calibrated in the 1980s. These factors were last updated in 2014, prompted by changes in the Canadian standard for reinforced concrete structures (CSA A23.3-14). However, a rigorous, masonry-specific reliability analysis was not performed to support the strength reduction factors used in S304-14. Therefore, there are safety and economic uncertainties in the performance of masonry elements designed in accordance with the strength reduction factors in the 2014 (reaffirmed in 2019) version of the Canadian masonry standard. In this thesis, a reliability analysis for reinforced, concrete masonry walls (RMWs) under axial compression and out-of-plane uniform load is presented, along with the development of a limit state function that incorporates second-order effects. The analysis is performed using currently available probability information on loads and strength of reinforced concrete masonry walls, realistic loading conditions, and the Monte Carlo method to calculate reliability indices. The aim of this analysis is to evaluate the structural safety and performance of RMWs under the specified loading conditions. An innovative part of the analysis is that it takes into account realistic loads and second-order effects, both aspects that seem to be scant in the limit state function formulations found in the literature. A range of different slender walls are analysed in this study, varying their slenderness ratio, cross-section properties and load relationships. The results show that the reliability indices () increase as the slenderness factor increases, while for walls with low slenderness, the reliability indices remain similar and constant over different eccentricities.