Prestressed FRP Systems

Michels, Julien; Barros, Joaquim A. O.; Costa, Inês; Sena-Cruz, José; Czaderski, Christoph; Giacomin, Giorgio; Kotynia, Renata; Lees, Janet M.; Pellegrino, Carlo; Zīle, Edmunds

doi:10.1007/978-94-017-7336-2_7

Cited by 16 publications

(16 citation statements)

References 58 publications

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“…For externally bonded FRP strips, we can distinguish systems where the prestressing force is introduced through hydraulic jacks and which demand a kind of mechanical anchorage at the end of the strip, and so‐called gradient anchorage systems. The latter do not need any external mechanical anchorages and are based on adhesive bonding of a certain length of a strip to the concrete surface, in several steps reducing the prestressing force until the force reaches zero at the end of the strip .…”

Section: Researchmentioning

confidence: 99%

Prestressing concrete members with fibre‐reinforced polymer reinforcement: State of research

Zdanowicz

Kotynia

Marx

2019

Structural Concrete

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The technology of prestressing concrete structures has been a well‐established field in structural engineering since the last century. Nowadays, new materials developed for reinforcing concrete structures, such as fibre‐reinforced polymers (FRPs), open further possibilities for engineers. FRP tendons are more and more often investigated as an efficient and suitable material for prestressing, and there are already some field applications of this technology. This paper aims to describe the current state of knowledge in the field of prestressing with FRP tendons, with regard to available materials, developed anchorages and undertaken investigations. Researches conducted in areas such as bond strength, ductility, durability, long‐term behavior, and high‐temperature resistance are described and summarized. Our goal was to provide a summary of what has been achieved so far in the research field of prestressing concrete structures with FRP tendons; however, field applications and standardization issues are not part of this review.

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Section: Researchmentioning

confidence: 99%

Prestressing concrete members with fibre‐reinforced polymer reinforcement: State of research

Zdanowicz

Kotynia

Marx

2019

Structural Concrete

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“…The prestressing of the CFRP strips has the advantages that the serviceability of the structure can be increased, i.e., the deformations and crack widths are decreased and the CFRP material is better utilized. Nowadays, several products are available on the marked to apply prestressed CFRP strips [20].…”

Section: Research On Prestressed Ebr Cfrpmentioning

confidence: 99%

“…The idea of prestressing the CFRP laminates was firstly studied in a PhD thesis work by Deuring [20]. The prestressing of the CFRP strips has the advantages that the serviceability of the structure can be increased, i.e., the deformations and crack widths are decreased and the CFRP material is better utilized.…”

Section: Research On Prestressed Ebr Cfrpmentioning

confidence: 99%

EBR Strengthening Technique for Concrete, Long-Term Behaviour and Historical Survey

Czaderski

Meier

2018

Polymers

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Epoxy bonded steel plates (externally bonded reinforcemen: EBR) for the strengthening of concrete structures were introduced to the construction industry in the late 1960s, and the use of fibre reinforced polymers (FRPs) was introduced in the 1990s, which means that these techniques have already been used in construction for 50 and 25 years, respectively. In the first part of the paper, a historical survey of the development and introduction of these strengthening techniques into the construction industry are presented. The monitoring of such applications in construction is very important and gives more confidence to this strengthening technique. Therefore, in the second part of the paper, two long-term monitoring campaigns over an extraordinarily long duration will be presented. Firstly, a 47-year monitoring campaign on a concrete beam with an epoxy bonded steel plate and, secondly, a 20-year monitoring campaign on a road bridge with epoxy bonded CFRP (carbon fibre reinforced polymers) strips are described. The paper is an expanded version of the paper presented at the SMAR2017 Conference.Keywords: externally bonded reinforcement; EBR; strengthening of reinforced concrete; epoxy adhesive; bond; steel; CFRP; long-term behaviour Historical Survey of Development of EBR Technique Research on EBR SteelThe first ideas on strengthening of concrete with epoxy bonded steel plates were presented in the 1960s by L'Hermite et al. Figure 1 showing the principle idea of applying a steel plate to a concrete beam with an adhesive (tole d'acier: steel plate and colle: adhesive). The first applications on a highway bridge and in a building followed in 1966-1967 [3]. Bresson [2] presented in the year 1971 the derivation of the differential equation of bond behaviour of EBR and its elastic solution. Afterwards, other researchers worked on that topic-for example, Johnson et al. [4] presented in 1981 a research study on sixteen tests on plated reinforced concrete members subjected to bending, shear and axial tension, in order to study the influence of geometric parameters on the maximum tensile strain that can be developed in a mild steel plate before breakdown of the adhesive layer or failure of the concrete member. No failures occurred in the epoxy adhesive, and strains exceeding yield could be developed in the plates. Furthermore, Dussek [5] described results of tests on plate-reinforced beams, discussed a design method and presented strengthening projects where steel plates were applied on several bridges in UK. A timeline of the developments discussed is displayed in Figure 2.In the 1970s and 1980s, besides the investigations mentioned above, research on the performance and on a better understanding on the epoxy bonded steel plates was also performed at Empa in City,

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“…In (Deuring, 1993), mechanical anchorages were used to transfer the prestressing forces from the composite to the concrete substrate. Subsequently, several researchers dedicated their work to develop applications of bonded prestressed FRP; more details can be found in (Motavalli et al, 2011;Michels et al, 2016a). The advantages of using prestressed FRP (P-FRP) can be compared to those of conventional prestressed concrete structures.…”

Section: Introductionmentioning

confidence: 99%

“…All the metallic mechanical systems must be permanently fixed to the concrete with screws or dowels. The anchorage system requires a minimum of adhesive curing, which implies that the prestress force at the ends is generally fully released one day after the installation (Michels et al, 2016a).…”

Section: Introductionmentioning

confidence: 99%

The Gradient Anchorage Method for Prestressed CFRP Strips: from the Development to the Strengthening of an 18 M Long Bridge Girder

Breveglieri

Czaderski

Michels³

2018

Slovak Journal of Civil Engineering

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The external bonding of carbon fiber-reinforced polymer (CFRP) strips by two-component epoxy adhesive on the concrete surfaces of buildings and bridges is a retrofitting method accepted worldwide. The gradient anchorage (GA) is an anchoring method especially developed to anchor prestressed CFRP strips to concrete elements without a need for mechanical clamping after the installation phase. This method takes advantage of the adhesives property to undergo accelerated curing when heated. The results of more than fifteen years of research on the development of the gradient anchorage at the Swiss Federal Laboratories for Materials Science and Technology (Empa) are presented in this paper. The basic principles and application steps are explained, and the main results starting from the development of the technique up to the testing of real scale girders are described, and the new challenges posed by this innovative system are highlighted. The gradient anchorage is a valid alternative to a mechanically anchored system for prestressed FRP (P-FRP).

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Prestressed FRP Systems

Cited by 16 publications

References 58 publications

Prestressing concrete members with fibre‐reinforced polymer reinforcement: State of research

Prestressing concrete members with fibre‐reinforced polymer reinforcement: State of research

EBR Strengthening Technique for Concrete, Long-Term Behaviour and Historical Survey

The Gradient Anchorage Method for Prestressed CFRP Strips: from the Development to the Strengthening of an 18 M Long Bridge Girder

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