A review of the present and future utilisation of FRP composites in the civil infrastructure with reference to their important in-service properties

Near-surface mounted (NSM) fiber-reinforced polymer (FRP) reinforcement is one of the latest and most promising strengthening techniques for reinforced concrete (RC) structures. Research on this topic started only a few years ago but has by now attracted worldwide attention. Issues raised by the use of NSM FRP reinforcement include the optimization of construction details, models for the bond behaviour between NSM FRP and concrete, reliable design methods for flexural and shear strengthening, and the maximization of the advantages of this technique. This paper provides a critical review of existing research in this area, identifies gaps of knowledge, and outlines directions for further research.

Near-surface mounted FRP reinforcement: An emerging technique for strengthening structures

This paper presents the results of a recent study conducted to refine the design-oriented stress–strain model originally proposed by Lam and Teng for fiber-reinforced polymer (FRP)-confined concrete under axial compression. More accurate expressions for the ultimate axial strain and the compressive strength are proposed for use in this model. These new expressions are based on results from recent tests conducted by the writers’ group under well-defined conditions and on results from a parametric study using an accurate analysis-oriented stress–strain model for FRP-confined concrete. They allow the effects of confinement stiffness and the jacket strain capacity to be separately reflected and accounts for the effect of confinement stiffness explicitly instead of having it reflected only through the confinement ratio. The new expressions can be easily incorporated into Lam and Teng’s model for more accurate predictions. Based on these new expressions, two modified versions of Lam and Teng’s model are present...

/pdf/refinement-of-a-design-oriented-stress-strain-model-for-frp-e9qunoayrf.pdf

Refinement of a design-oriented stress-strain model for FRP-confined concrete

https://www.quakewrap.com/frp%20papers/Progress-On-Understanding-Debonding-Problems-In-Reinforced-Concrete-And-Steel-Members-Strengthened-Using-FRP-Composites.pdf

Progress on understanding debonding problems in reinforced concrete and steel members strengthened using FRP composites

In this paper, a stress–strain model for concrete confined by fiber reinforced polymer (FRP) composites is developed. The model is based on the results of a comprehensive experimental program including large-scale circular, square and rectangular short columns confined by carbon/epoxy and E-glass/epoxy jackets providing a wide range of confinement ratios. Ultimate stress, rupture strain, jacket parameters, and cross-sectional geometry were found to be significant factors affecting the stress–strain behavior of FRP-confined concrete. Such parameters were analyzed statistically based on the experimental data, and equations to theoretically predict these parameters are presented. Experimental results from this study were compared to the proposed semi-empirical model as well as others from the literature.

/pdf/stress-strain-model-for-concrete-confined-by-frp-composites-3r17hpnnly.pdf

Stress-strain model for concrete confined by FRP composites

*Co-chairs of the subcommittee that prepared this document. Note: The committee acknowledges the contribution of associate member Paul Kelley. ACI encourages the development and appropriate use of new and emerging technologies through the publication of the Emerging Technology Series. This series presents information and recommendations based on available test data, technical reports, limited experience with field applications, and the opinions of committee members. The presented information and recommendations, and their basis, may be less fully developed and tested than those for more mature technologies. This report identifies areas in which information is believed to be less fully developed, and describes research needs. The professional using this document should understand the limitations of this document and exercise judgment as to the appropriate application of this emerging technology.

/pdf/guide-for-the-design-and-construction-of-externally-bonded-3wakai247t.pdf

Karl Gillette

Papers

Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures