Stress-Strain Characteristics of Clay Brick Masonry under Uniaxial Compression

TLDR

The uniaxial monotonic compressive stress‑strain behavior and other characteristics of unreinforced masonry and its constituents, i.e., solid clay bricks and mortar, have been studied by several laboratory tests. A simple analytical model based on linear regression uses only the compressive strengths of bricks and mortar to predict masonry stress‑strain curves for analysis and design. Experimental results yielded nonlinear stress‑strain curves for bricks, mortar, and masonry, identified six control points to define performance limit states, derived simple relationships linking modulus of elasticity to compressive strength, and showed that masonry curves need not lie between those of bricks and mortar even when the constituents have similar strength and stiffness.

Abstract

The uniaxial monotonic compressive stress-strain behavior and other characteristics of unreinforced masonry and its constituents, i.e., solid clay bricks and mortar, have been studied by several laboratory tests. Based on the results and observations of the comprehensive experimental study, nonlinear stress-strain curves have been obtained for bricks, mortar, and masonry and six "control points" have been identified on the stress-strain curves of masonry, which can also be used to define the performance limit states of the masonry material or member. Using linear regression analysis, a simple analytical model has been proposed for obtaining the stress-strain curves for masonry that can be used in the analysis and design procedures. The model requires only the compressive strengths of bricks and mortar as input data, which can be easily obtained experimentally and also are generally available in codes. Simple relationships have been identified for obtaining the modulus of elasticity of bricks, mortar, and masonry from their corresponding compressive strengths. It was observed that for the strong and stiff bricks and mortar of lesser but comparable strength and stiffness, the stress-strain curves of masonry do not necessarily fall in between those of bricks and mortar.