Seismic Strengthening of Existing RC Columns with Polymer Cement Mortar Sprayed by Dry System

Abstract

The authors developed a new seismic strengthening method for existing RC columns. In this new method, the shear reinforcing bar, for example re-bar, welled mesh, carbon fiber grid, is mounted around the column, and special polymer cement mortar is sprayed by dry spray system over the shear reinforcing bar. Seismic strengthening effect of existing RC columns with the new method was estimated based on the results of reversed cyclic loading test for the strengthened RC columns. It was cleared that the new method was very applicable for seismic strengthening of existing RC columns from the points of both ductility capacity and shear carrying capacity. Furthermore, the equations for the ultimate shear strength of the columns strengthened by the new method were proposed.