Experimental study on reinforced concrete columns having wing walls retrofitted with continuous fiber sheets

Abstract

In this paper the results of a series o f tests, which were carried out using a total of 16 specimens o f reinforced concrete (RIC) columns having wing walls retrofitted with fiber reinforced polymer (FRP) sheets as shear reinforcement, are described. In this work, the FRP sheets were adhered with epoxy resin. The specimens before retrofit were designed by the abolished Japanese seismic code before 1971. The primary test variables were the widths o f the wing walls stretching from the columns, the kind o f FRP sheets and its amount as shear reinforcement. I t was observed that all specimens failed in a shear mode except for one specimen and that the ultimate shear strengths increased linearly in proportion to the amount o f the fiber as shear reinforcement. (i.e., the product of tensile strength and equivalent reinforcement ratio which corresponds to an replaced rectangular cross section o f the column and the wing walls as a whole.) Based on the test results o f regression analysis, an equation to evaluate the ultimate shear strength o f RIC columns having wing walls retrofitted with FRP sheets is proposed.