Rapid and Affordable Seismic Retrofit of Substandard Confined Masonry

Abstract

Confined masonry (CM) consists of unreinforced masonry walls confined with reinforced concrete tie columns and beams. Due to satisfactory performance during past earthquakes, CM has become the predominant construction style in several developing countries. However, poor construction practices and substandard materials may result in inadequate performance.This paper evaluates the feasibility and efficiency of an affordable and practical retrofit technology designed for CM constructions in developing areas. Corrosion-resistant aluminum strips are inserted into grooves and embedded in mortar along bed joints to enhance the in-plane shear resistance and deformability. Experimental evidence was obtained through in-plane cyclic load tests on full-scale CM walls. It is shown that a substandard CM wall can be transformed into a wall with acceptable strength and deformability, and the in-plane shear strength of a retrofitted wall can be estimated by means of a simple analytical model that accounts for the contribution of the horizontal reinforcement.

Force‐displacement model for solid confined masonry walls with shear‐dominated failure mode

“…Note that in determination of the compressive capacity of the FT (F YFT ), which is determined considering axial force-flexural moment interaction, the effects of the generated bending moments at the base of this tie is also considered. This assumption is valid considering moments in the form of horizontal cracks at the tensile face in ties have been reported [28,33,[42][43][44][45][46][47][48]. It can generally be concluded that the lower the L/H, the higher the forces and the higher the generated moments in the ties are.…”