Experimental and analytical assessment of different anchorage systems used for CFRP flexurally retrofitted exterior RC beam-column connections

Abstract

The current study presents the results of an experimental program on the application of carbon-fiber reinforced polymer (CFRP) composites to improve the lateral strength capacity of exterior reinforced concrete (RC) beam-column connections. In such connections, the CFRP composites are bonded onto the top and bottom sides of the beam; however, the presence of the column restricts continuation of FRP composites beyond the end critical sections at the column interface. To provide continuity for composites across the joint, four different anchorage systems have been evaluated through experiments on five half-scale RC connections, comprising an as-built and four retrofitted ones, under reversed cyclic loading. The experimental results demonstrated the superior performance of 180-degree anchor fan among all the tested anchorage systems, leading to a complete plastic hinge relocation along the beam from the column face. Analytical investigation employing a fiber section (FS) modelling approach was also performed and the results validated against the experimental ones. The verified model was then exploited to investigate the effect of FRP composites length along the beam on the structural behavior of RC beam-column connections.