Analytical Model for Estimating the Out-of-Plane Behaviour of Masonry

The use of brick masonry infill walls is a common technique in reinforced concrete (RC) frames. Although classified as non-structural elements and often neglected in design frameworks, they can influence the seismic performance of RC frames by increasing the overall structural stiffness. Furthermore, they can introduce significant structural irregularities and be responsible for brittle failure mechanisms such as soft-floor mechanisms. This paper aims to present a newly developed analytical model for evaluating the lateral out-of-plane (OOP) behaviour of diverse masonry infill walls. This model incorporates vertical and horizontal arch mechanisms, accounts for the flexibility of the RC frame elements surrounding the panel (such as upper beams and columns) and considers potential external reinforcement solutions. The model calibration is based on from earlier experimental studies for thin and thick infill walls, both reinforced and unreinforced also considering in previous in-plane (IP) damage assessments. Finally, the paper presents a parametric analysis based on this framework, offering insights into the influence of the main vulnerability parameters of infills on their OOP performance.