A modified fiber‐reinforced plastics concrete interface bond‐slip law for shear‐strengthened RC elements under cyclic loading

The objective of this article is to realistically analyze fiber‐reinforced plastics (FRP) retrofitted reinforced concrete structures under cyclic loading taking into account FRP–concrete bond‐slip law with cyclic bond degradation. In literature, even though numerous studies have been conducted in FRP–concrete interface bond‐slip modeling under cyclic loads, a small number of them consider the influence of cyclic degradation on FRP–concrete interface bond behavior. Within this framework, the bond‐slip law for carbon fiber‐reinforced plastics–concrete interface is revised by utilizing Harajli's and Ko‐Sato's approaches. The procedure is distinct from others because it develops existing deficiencies of these approaches, whereas a more reliable modeling process is proposed for use in practice. Conventional bond‐slip law of Lu et al. is compared with this interface relationship stated in this investigation and the difference is clearly shown in terms of structural parameters. Experimental tests are conducted at the same time for verification. It is proved that cyclic bond degradation affects the interface behavior; thus, the structural response cannot be omitted in structural evaluations. Structural performance measures are obtained in good agreement for each level of cycles. The technique proposed clearly exhibits structural response difference between monotonic and cyclic loadings while good agreement is reached with experimental results. POLYM. COMPOS., 37:3373–3383, 2016. © 2015 Society of Plastics Engineers