Structural Upgrade of Reinforced Concrete Column-Tie Beam Assembly using FRP Composites

ABSTRACT

The paper discusses the potential use of fiber reinforced polymer composites for repair and retrofit of existing reinforced concrete (RC) column-tie beam assemblies. Results of an experimental program performed on large-scale specimens repaired and strengthened with two types of wet lay-up composite systems are presented. Each column-tie beam assembly specimen was subjected to a constant axial load simulating gravity loads, and incremental cyclic lateral loads simulating potential seismic forces. Displacements, strains and loads were continuously monitored and recorded during all tests. Evaluations of the observed strength and ductility enhancements of the strengthened specimens are made and limitations of such retrofit methods are highlighted for design purposes. Experimental results indicated that the two composite systems used in this study succeeded in enhancing the strength, stiffness and the ductility of the column-tie beam assembly. As compared to the unstrengthened specimens, the strengths of the retrofitted specimens were 152% and 154% for carbon/epoxy and E-glass/epoxy composite systems, respectively.

Keywords 

FRP composites; moment connections; seismic