Seismic shear strengthening of R/C columns with ferrocement jacket

This paper presents results of an experimental study to evaluate a retrofit technique for strengthening shear deficient short concrete columns. In this technique a ferrocement jacket reinforced with expanded steel meshes is used for retrofitting. Six short concrete columns, including four strengthened specimens, were tested. Specimens were under a constant compressive axial force of 15% of column axial load capacity based on original concrete gross, Ag, and the concrete compressive strength, fc′. Main variables were the spacing of ties in original specimens and the volume fraction of expanded metal in jackets. Original specimens failed before reaching their nominal calculated flexural strength, Mn, and had very poor ductility. Strengthened specimens reached nominal flexural strength and had a ductility capacity factor of up to 5.5. Based on the test results, it can be concluded that ferrocement jackets reinforced with expanded steel meshes can be used effectively to strengthen shear deficient concrete columns.