Seismic performance enhancement of brick masonry walls by retrofitting with nominal RC bands: a study of diagonal compression tests

Abstract

In-plane performance of un-reinforced brick masonry (URBM), retrofitted with nominal Reinforced Concrete (RC) bands, was investigated under diagonal compression tests using full-scale and half-scale specimens. The retrofitting technique is cost-effective, reliable, simple, easily implementable, and minimally intrusive. Six URBM wall specimens (three full-scale and three half-scale) served as control specimens, and similarly, six (three full-scale and three half-scale) were retrofitted with RC bands. All specimens were tested under diagonal compression in a computer-controlled servo-hydraulic universal testing machine using displacement-controlled scheme. Data on applied force and corresponding wall displacements were recorded. Responses of retrofitted specimens were compared with control specimens in terms of strength, deformation capacity, and failure patterns. Retrofitted specimens exhibited progressive damage due to ductile failure, showing a significantly increased deformation capacity and providing sufficient warning time before collapse. However, control specimens showed sudden catastrophic collapse due to sliding of bed-joints. Overall, retrofitted specimens demonstrated a significant enhancement of ductility. Next, a semi-empirical prediction formula for diagonal load capacity was established through macro-modelling approach and subsequent regression analysis to capture experimental results. From results, the proposed retrofitting scheme provides a promising solution for seismic risk reduction of existing deficient masonry structures in rural areas of the Indian subcontinent and elsewhere.