An Experimental and Numerical Study to Sustain Flexural Capacity in Precast RC Joints using FRP Sheets

This paper is focused on the results of the experimental investigation and numerical analysis for changing the precast RC beam-column connections with corbels to flexural connections using fiber reinforced polymers (FRPs). The experimental study has a special focus on the flexural strength and debonding effect of boundary layer of FRP sheets attached onto the corbels and other parts of precast connections. In the current study, four half-scale external beam-to-column connections including one conventional fixed connection, and three simple precast connections with corbels strengthened withFRP sheets were casted and tested. The FRP sheets were attached in different layouts with different thicknesses. Static concentrated loads were applied on the tip of the beam simultaneously with a constant axial load on the column, and were continued up to ultimate failure. To fulfill the numerical phase of this study, non-linear static analysis on the 3-D model of the connections were performed using Ansys 8.1. A comprehensive comparison was then performed between different strengthening methods with FRP sheets using different FRP configurations, different thicknesses and dimensions, also using full mechanical anchorages. The results showed that simple precast connections could be changed to flexural connections using FRPs, whereas the sufficient development length and thickness, configuration of FRP sheets, and suitable mechanical anchorage are quiteeffective to prevent the FRP debonding. The test results of this study showed that the suitable use of FRP sheets increased the flexural capacity of a simple precast joint more than 80% of that of a full flexural RC joint.