Experimental Research on Bond Behavior between GFRP Bars and Stirrups-Confined Concrete

Abstract

This paper presents the results of a series of pullout tests that were performed on Glass-fiber-reinforced polymer (GFRP) bars embedded in concrete, while providing a detailed report on the influence of various variables that impinge upon bond behavior, such as the surface characteristics and diameter of the bars, concrete strength, as well as the confined effect of stirrups. The Bertero-Popov-Eligehausen (BPE) and Cosenza-Manfredi-Realfonzo (CMR) models analyzed the bond stress (τ)–slip (s) relationship between GFRP bar and stirrups-confined concrete. The tests results indicate that when the bond failure interface only occurs on the surface of a GFRP bar, the bond strength is not dependent upon the concrete strength. Moreover, the results indicate that in comparison to specimens without stirrups, their stirrup-containing counterparts are more prone to pullout failure with greater ductility and higher bond strength and corresponding slip. The BPE and CMR models are able to investigate the τ-s relationship between GFRP bars and the stirrups-confined concrete with accuracy. With the experimental data, the specific parameters in the models classified by surface characteristics have been suggested.

Experimental investigation on the bond performance of sea sand coral concrete with FRP bar reinforcement for marine environments

“…Based on the typical bond-slip curves obtained from this test, the rising and falling stages of the bond-slip curves were fitted with the GDY model curve (Gao et al, 2009), quadratic model curve and mBPE model curve (Cosenza et al, 1996) to establish the bond-slip constitutive relationship between the FRP bar and SSCC. The GDY model and the quadratic model were used to compare the rising stage of the bond-slip curve of the SSCC with FRP bars, and the specific models are given in equations (2) and (3).…”

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“…Different types of fibers could be distinguished according to their characteristics, which condition their use. Glass fibers are widely used in the production of structural composites in the aerospace, nautical and automotive fields, associated with different matrices, for example polyamide or epoxy, still synthetic resins [13][14][15]. Glass fiber is largely used in dental field, for single, multi teeth restauration ( Figure 1).…”

Bond behavior of BFRP bars in concrete under lateral pressure

“…The yield and transverse (stirrup) restraint of reinforcement are considered by establishing the corresponding reduction factor. Based on the study of the bond behavior of reinforced concrete under lateral pressure, Gao [20] tested the drawing specimens of glass FRP bars confined by stirrups, which showed that the confinement of stirrups to concrete changed the failure mode of concrete and the bond strength of the specimen's increases with the corresponding slip growth. The above research shows that the bond performance between reinforcement and concrete is obviously affected by the lateral compressive stress, of which the influence on the bond performance is specified in the code.…”