Reliability and Structural Performance Assessment of Solid Concrete Block Masonry Prisms using Compressive Strength Modelling and Monte Carlo Simulations

Abstract

Solid concrete block masonry is widely used in construction, but its performance is affected by variability in material properties, workmanship, and block quality. Traditional deterministic design methods often fail to capture these uncertainties, potentially leading to unsafe designs. This research proposes a reliability approach to assess masonry prism compressive strength through the integration of predictive modelling and probabilistic analysis. The objective is to perform a reliability analysis of masonry prisms and determine the Probability of failure. Five cement-sand mortar ratios (1:3 to 1:7) were experimentally evaluated, and Multiple Linear Regression (MLR) models were developed to estimate prism strength as a function of block and mortar strengths. The developed regression equations were incorporated into a Monte Carlo simulation framework with 40,000 iterations to evaluate the Probability of failure and reliability index for a typical residential building configuration. Results indicate that the 1:3 mortar mix provides superior structural performance, yielding a probability of failure (𝑃𝑓) of 0.0479 and a reliability index (𝛽) of 1.66, satisfying the adopted target reliability criterion. Floor optimization analysis further revealed that the structure can safely support up to 14 floors while maintaining the adopted Probability of failure limit of 5%. The findings highlight the significant influence of material variability on masonry reliability and demonstrate the effectiveness of probabilistic methods for realistic safety assessment and performance-based masonry design.