Confinement of FRP concrete columns: Review of design guidelines and comparison with experimental results

A regulatory framework is required to ensure the correct design of Fibre-Reinforced Polymers (FRPs) increasingly being used as an externally-bonded strengthening system on concrete columns. Several design guidelines on the confinement of FRP concrete have been developed over the past few years worldwide, each proposing a different approach, resulting in different predictions. This study aims to evaluate and compare nine international design guidelines used to predict the compressive strength of confined concrete in FRP-strengthened concrete columns and weigh them against experimental results. The results of this investigation reveal that the predictions from the guidelines on the compressive strengthening of FRP-confined concrete are generally suitable for circular columns, with the ACI-440 and CNR-DT 200 guideline predictions being two of the most accurate. Nevertheless, the guidelines generally tend to overestimate the load-carrying capacity for the compressive strength of FRP-confined concrete in non-circular columns, for which further experimental work using large-scale specimens is required.