Core testing method to evaluate the nonlinear behavior of brick masonry under shear force

Recent studies have focused on the seismic vulnerability of masonry structures, particularly unreinforced masonry (URM) buildings, following the 2012 Emilia earthquake in Italy. URM structures, designed mainly for gravity loads, exhibit nonlinear behavior under compressive and shear stresses due to differing elastic properties of brick and mortar. This leads to micro-cracks that evolve into larger cracks, resulting in failure modes like splitting, crushing, spalling, and shear cracking. To assess URM’s shear response, conventional testing methods, such as those regulated by ACE-2018, are used. These tests provide critical insights into masonry’s strength, stiffness, and post-peak softening behavior. This study focuses on masonry behavior after diagonal cracking under 0.8 MPa vertical stress, which represents a critical failure point. The post-cracking response reveals important data on residual shear strength and the ability to resist further deformation under combined loads. A promising method for determining masonry shear strength involves core-drilling samples and conducting splitting tests with a rotated mortar layer, inducing a mixed compression-shear stress state. Digital Image Correlation (DIC) technology is integrated to track displacement and strain fields in real-time, offering detailed visualization of crack initiation and propagation. This combination of core sampling and DIC enhances shear strength evaluation by providing insights into localized deformations and identifying weak zones in the masonry structure.