Width Effect in FRP-Concrete Debonding Mechanism: A New Formula

This paper presents the results of an experimental work aimed at determining the effect of the width of a steel fiber-reinforced polymer (FRP) composite on the load-carrying capacity of a composite-concrete interface. Single-lap shear tests were performed in which the main parameter was the width of the composite strip. Steel FRP strips were applied to three different faces of each concrete prism and it was observed that the load-carrying capacity is strongly related to the face to which the composite is applied. In addition, a few tests were carried out at a displacement rate, used to control the test, equal to ten times the rate employed for the majority of the specimens. A great influence of the rate on the load-carrying capacity was observed, although the number of tests was limited. The authors argue that most of the width effect formulas available in the literature use data from different sources without taking into account the face of application and the rate. A new width effect formula is proposed, which takes into account the most recent articles on this subject.