Understanding the function of bonding courses in masonry construction: An investigation with mixed numerical methods

Bonding courses, also called leveling courses, are ubiquitous in historical masonry structures. While this technique is common, there is no clear understanding of their structural function. Many works have postulated that this construction typology denotes the end of a workday or the height of one shuttering. Additionally, many sources contradict each other about the structural functionality of bonding courses. While some works have claimed that they create a structural weakness, others have asserted that they must be a structural advantage since they are ubiquitous. The aim of this paper is to study the behavior of bonding courses to understand their potential structural functionality. Using a mixed numerical method, i.e., combining finite element modeling and distinct element modeling, the structural response of the bonding courses is simulated. Under differential settlement of foundations, damages were seen to be localized in the walls with bonding courses. Performed analysis indicates that bonding courses had a positive contribution to the structural safety of the walls. A study of how the height of the bonding course affects this performance was also carried out.