Bond and strain behavior of horizontal reinforcement in masonry mortar joints

Abstract

To answer some of the questions about the behavior of wire joint reinforcement in mortar, a research investigation was conducted, the details of which are included in the herein. Particularly, the research program is aimed at determining the strain energy that can be absorbed by different wire joint reinforcement configurations (different coatings anddiameters) to address the criticisms of the previous research projects on the ability of wire joint reinforcement to satisfy horizontal reinforcement requirements. The two issues addressed were the strain capacity of the wire joint reinforcement embedded in a mortar joint and the mechanical properties of the wire when subjected to conventional tension tests. Two main factors are involved with the strain capacity of the wire when embedded in mortar. First, the mechanical stress-strain properties of the wire itself play a large role. Second the interaction of the wire and the mortar plays an equally important role. The experimental evaluation of the mortar/wire interaction is the most variable behavior to describe and is dependent on the surface conditions of the wire, the amount of applied surcharge (axial stress), and the character of the mortar. All of these factors determine the length over which the wire may be stressed and strained. This length, labeled "effective gage length" in this paper, provides a convenient means by which the behavior of wire joint reinforcement embedded in mortar may be described and evaluated as a suitable replacement for bond beams in masonry shear walls.