FERROCEMENT FOR REPAIR AND RETROFITTING OF BRICK MASONRY SHORT COLUMNS

Abstract

Brickwork is one of the oldest building materials, used for the construction of walls, columns etc. to resist mainly the compressive loads. In India more than 35% of buildings have been constructed in brick masonry. Ferrocement encasement can be applied with advantage to brick masonry columns to strengthen new construction and for repair or retrofitting in existing columns. The wire mesh encasement resists the lateral expansion of the column core caused by the vertical compression. This introduces lateral confinement, and structural properties of masonry are modified. The objective of the present investigation is to experimentally study the behaviour of brick masonry columns, repaired by ferrocement encasement and subjected to axial compression. The main issue is to examine if jacketting of brick masonry columns by ferrocement helps in providing a substantial strength increase as in case of concrete. Also load-deformation behaviour and cracking particularly first appearance of the visible cracks was one of the objectives. The experimental programme consisted of casting 20 columns, divided into two groups. First group was of undamaged specimens, which were encased in ferrocement. Second group's specimens were damaged specimens, which were repaired with different quantities of mesh. All specimens were tested at 28 days under axial compression. The test data recorded were ultimate loads, strains in longitudinal direction and first crack load. All the data were processed and comparative studies were carried out for gain in strength and finally relevant conclusions drawn from the study. These show that ferrocement encasement was highly effective for repair of both damaged and undamaged columns. Hence this technique can be applied for the repair of columns damaged due to various causes and for strengthening and retrofitting of columns.