EXAMINER'S COMMITTEE

Abstract

Confined masonry is one of the common forms of low-rise constructions throughout the world; including Mexico, South and Central America, South-East Asia, Middle East, and South-Eastern Europe. The system relies on a load-bearing wall surrounded by small cast-in-place reinforced concrete tie columns and bond beams. The distinguishing feature of confined masonry construction is that the masonry wall is constructed prior to the casting of tie columns and bond beams, thus both elements respond integrally when subjected to lateral loads. In general, tie columns have a square section whose dimensions typically correspond to the wall thickness. For bond beams, both wall thickness and floor type influences the choice of the dimensions. The confining elements are intended to confine the masonry panel preventing disintegration, to enhance wall deformation capacity, and connectivity with other walls and floor diaphragms. The requirement of recent European codes the contribution of vertical confinement to vertical and lateral resistance should be ignored. The amount of reinforcement is determined arbitrarily on the basis of experience, and depends on the height and size of the building. In a way, the behavior is similar to that of reinforced concrete frames with masonry infill. However, in the case of confined masonry, tie-columns do not represent the load-bearing part of a structure. The in-plane response of a confined masonry wall is distinctly different from that of reinforced concrete in filled frames, where the frame is constructed prior to the masonry infill. The frame is constructed prior to the masonry infill. Although a confined masonry wall experiences both flexural and shearing deformations, the masonry infill deforms in a shear mode within a frame that attempts to deform in flexure, resulting in separation of the frame and infill wall along the tension diagonal.