A comprehensive analysis of the scrapping and abandonment of fiber-reinforced polymer vessels at sea.

Monitoring of FRP Strengthened Concrete Structures Using FBG Sensors

Fiber reinforced polymer (FRP) has been used in the construction industry because of its advantages such as high strength, light weight, corrosion resistance, low density and high elasticity. This paper presents a review of bonding techniques adopted to strengthen timber beams using FRP to achieve larger spans. Different methods of bonding between FRP and timber beams have been summarized with a focus on the influencing factors and their effects as well as relevant bond-slip models proposed for fundamental understanding. Experimental investigations to evaluate the flexural performance of timber beams strengthened by FRP bars, sheets and wraps have also been critically reviewed to identify key influencing parameters. Limited research available on the shear performance of FRP reinforced timber beams have been analyzed to determine the influencing factors of the shear performance in timber-FRP beams. The paper finally presents an overall summary of the current-state-of-the-art and proposes some future research directions in the field.

Tiny yet tough: Maximizing the toughness of fiber-reinforced soft composites in the absence of a fiber-fracture mechanism

A state-of-the-art review on experimental investigation and finite element analysis on structural behaviour of fibre reinforced polymer reinforced concrete beams

The use of Fiber Reinforced Polymer (FRP) Composites is one of the latest significant developments in the field of bridge construction. FRP composites have been the material of choice in the aerospace industry since 1960s. However, only recently glass FRP composites have been gaining both popularity and acceptance as one of the structural materials of choice because of their high strength and stiffness to weight ratio, and corrosion resistance. This paper demonstrates the possibility of combining composite materials with a low-cost construction material (i.e. concrete) resulting in a new concept of designing lightweight, corrosion immune, yet inexpensive beams having acceptable structural properties. Pultruded FRP beam section-to-concrete slab is proposed to behave under bending as a composite beam. The objectives of the proposed research are to investigate the composite behaviour of FRP members with reinforced concrete slabs and comparing the behaviour of fully encased FRP beams with that of FRP beams mechanically anchored to the concrete. An experimental program was conducted to demonstrate the behaviour of the pultruded FRP beam-toconcrete slab in composite action. Three large scale specimens of 2.25 m length were tested under four-point loading. The first specimen is a pultruded FRP beam used as a control beam. The second specimen consists of pultruded FRP beam-to-concrete slab acting as a composite beam. The third specimen is a fully concrete encased FRP beam. The test results indicated the feasibility of using hybrid FRP-concrete beam to increase the load carrying capacity in flexure as well as beam stiffness. The outcome of this research provides substantial information for both designers and researchers in the field of FRP composites.

Composite materials offer superior strength-weight ratios, corrosion resistance, and durability, making them ideal for restoring and reinforcing equipment. Analytical approaches employ mathematical models, while numerical analysis, particularly finite element analysis (FEA), simulates stress, strain, and failure, experimental analysis evaluates repair effectiveness. This research emphasizes fiber-reinforced polymers (FRP) for pipeline defect repairs, showcasing high tensile strength, corrosion resistance, and lightweight properties. For a case study involving a natural gas pipeline repair, the chapter details the calculation of the minimum required thickness of the GFRP composite. Depending on the material used, the number of layers required to meet strength demands varies, with examples showing 91 layers for MCM composite material and 30 layers for TDW composite, demonstrating the relationship between material properties and repair design. Numerical simulations using FEA predict FRP repair performance, aiding decision-making and ensuring safety standards. Results show that composite repairs can maintain stress states below 290 MPa in pipelines (considering a steel with a yield strength of 360 MPa) with varying defect depths (d/t ratios). Furthermore, experimental tests validate the quality of GFRP composite repairs, demonstrating failure at pressures exceeding design limits, with composite coatings functioning as rupture stoppers at pressures of approximately 31.5 MPa. The chapter details design steps for Defect Type A repairs according to ISO 24817, including risk assessment, material selection, and design calculations for minimum repair laminate thickness. Relevant ISO, ASTM, BS, and ASME standards are discussed to ensure repair reliability and safety.

Properties and applications of FRP in strengthening RC structures: A review

The utilisation of fibre reinforced polymers (FRPs) as reinforcement for concrete elements has attracted attention mainly due to their high tensile strength, light weight and corrosion resistance. Lately, there has been an interest in basalt FRPs as a more economically competitive and environmentally friendly option. Basalt FRP is manufactured from a widely available volcanic rock in a process which does not require any additives, giving it an edge over the currently more popular glass-fibre reinforced plastic (GFRP) reinforcement. Pretensioning of FRP reinforcement with low longitudinal modulus of elasticity, such as GFRP and BFRP has been proposed as an effective solution to the concerns regarding the serviceability performance of flexural elements reinforced with these composite materials. In previous research it has been demonstrated that prestressing even at low levels can significantly reduce deflections and postpone cracking of BFRP reinforced concrete elements. This research presents an experimental investigation of pretensioned BFRP reinforced concrete tested under quasi-static loading and unloading cycles at 5kN load increments until failure. A comparison with an unprestressed sample is also provided to examine the effectiveness of prestressing at improving the structural performance of the beams. The samples were equipped with internal strain gauges and linear displacement transducers to monitor the development of strains in the reinforcement, deflections and concrete surface strains during testing. Close monitoring of the anchorage zone and the development of cracks was also conducted. Based on the experimental results it can be concluded that the prestressing of BFRP reinforced beams delays the development of residual strains and residual displacements upon unloading. Furthermore, the increase in the prestress level further reduced the residual strain and displacements.

Key issues in the use of fibre reinforced polymer (FRP) composites in the rehabilitation and retrofitting of concrete structures

FRP (fiber reinforced polymer material) having a high specific strength and specific modulus, good corrosion resistance and other advantages. FRP materials in civil engineering industry has been more and more popular, and gradually become a hot issue in the world. In order to take full advantage of a variety of materials and overcome the problems in the FRP structure, this paper mainly studies the composite structure of FRP and traditional materials, namely FRP-concrete composite beam structure. The mechanical parameters of FRP (mainly including CFRP and GFRP) were selected. And the stress -strain diagram of FRP materials are drawn. Through tensile tests on FRP (including CFRP and GFRP), FRP was found to belong to brittle materials. As well as the mechanical properties of FRP materials, the ultimate load analysis, the decision to use CFRP as a composite beam structural stiffness of the research materials. When considering concrete shrinkage, creep, temperature difference effect, the stiffness of composite beam meets the requirement. The deflection of FRP- concrete composite beam is verified by mechanical formula. The change of the concrete stiffness will affect the change of the structural stiffness of the FRP- concrete composite beam. As well as through an example, it is found that the concrete shrinkage and temperature can affect the change of the stiffness of the composite structure.

Fiber‐reinforced polymer (FRP) is an advanced composite material with many advantages including light weight, high strength, and high fatigue and corrosion resistance, which makes unidirectional FRP suitable for tension members, such as cables, prestressing tendons, and tie rods. However, the unidirectional FRP is a typical isotropic material, which is difficult to be anchored and hence unable to give full play to the advantages of FRP. To solve the anchoring problem of unidirectional FRP member, a novel bond anchor, i.e., dissolution‐rebond anchor, is proposed in this paper. In this novel anchorage system, the polymer matrix of two ends of the unidirectional FRP member is dissolved by solvent and the fibers in the anchorage length are directly bonded by the binder. Theoretical analysis was performed to illustrate the high anchorage bearing capacity of this dissolution‐rebond anchor. Static tensile test was conducted to verify this novel anchor design and compare with traditional bond anchor. Results show that the novel dissolution‐rebond anchor is feasible and its anchorage efficiency is significantly higher than the traditional bond anchor.

1 - Key issues in the use of fibre reinforced polymer (FRP) composites in the rehabilitation and retrofitting of concrete structures

Fiber reinforced polymer (FRP) bars represent a combination of the polymer binder and reinforcing fibers (glass, basalt, aramid, carbon). The main features of FRP bars are high tensile strength on the background of the relatively low elasticity modulus. To prevent development of the excessive both crack opening and deflections in the FRP reinforced concrete structures it can be effective to implement FRP reinforcement pretensioning with a limited level of created stresses. As a good option can be considered a physico-chemical method of FRP bars pretensioning based on the self-stressing concrete utilizing. In the self-stressed FRP reinforced members it is possible to obtain a considerable values of the early age restrained expansion strains (in comparison with steel reinforced self-stressed members because of FRP bars lower elasticity modulus), which will not disappear after air-dry shrinkage strains realization. In addition, another concern that have to be considered in the field of FRP reinforced self-stressed members is bond performance of the different FRP bars types, especially in combination with self-stressing concrete that within its expansion can provoke decompacting of the transit zone «bar-concrete». Moreover, taking into account that FRP bars is a composite material, its bond properties are strongly influenced by the types of the polymer binder, reinforcing fibers, ratio between binder and fibers, bar coating. Presented studies is consisted in the experimental investigations of the features in the crack development and depended on it occurred failure mode of the self-stressed members reinforced by the different types of FRP bars.

Concrete is one of the materials that is widely used in various structural works because it has advantages, especially it has high compressive strength and is easy to form. However, concrete can also be damaged by physical, chemical, mechanical and excessive loads. Damaged concrete structures must be repaired and strengthened immediately to prevent further damage that can lead to structural failure. One of the materials that can be used for structural reinforcement is Fiber Reinforced Polymer (FRP). FRP is a composite material made of three basic components, namely fiber, polymer and additives. FRP has advantages such as having high strength, light weight, corrosion resistance, easy installation, requiring little or no scaffolding. FRP is very well used to increase the capacity of structures in buildings that are undergoing changes in function

The application of Fiber Reinforced Polymer (FRP) materials in concrete structures has been rising due to their several advantages, including lightweight, high tensile strength, ease of installation, and corrosion resistance. They have been mostly implemented for strengthening and repairing existing structures in the form of an externally bonded system, i.e., sheet, jacket, near surface mounted. Furthermore, they have been recently utilized as internal reinforcement of concrete elements in the form of strands, bars, tendons, etc. Although higher durability and performance are associated with the FRP material in some aspects compared to steel, concerns remain regarding damages and defects in this material, many of which are related to their unique features. Importantly, debonding of FRP materials from a concrete surface or within a concrete element has always been an issue resulting in the premature failure of the structure. To this end, concrete elements strengthened or reinforced with FRP materials has to be inspected periodically to detect potential issues and hence prevent any premature failures. This study first determines all possible or potential damages and anomalies attributed to FRP reinforced/strengthened concrete (FRP-RSC) elements. It then investigates Non-Destructive Testing (NDT) methods that can be applicable to the inspection of FRP-RSC elements from a literature survey of past studies, applications, and research projects. Furthermore, this study evaluates the ability of two of the most commonly used NDT methods, Ground Penetrating Radar (GPR) and Phased Array Ultrasonic (PAU), in detecting FRP bars/strands embedded in concrete elements. GPR and PAU tests were performed on two slab specimens reinforced with GFRP (Glass-FRP) bars, the most commonly used FRP bar, with variations in their depth, size and configuration, and a slab specimen with different types of available FRP reinforcements. The results of this study propose the most applicable methods for detecting FRP and their damage/defects in FRP-RSC elements. This study further investigates the feasibility of two new methods for improving the detectability of embedded FRP bars. By providing the inspection community with more clarity in the application of NDT to FRP, this study offers means for verifying the performance and, therefore, help the proliferation of FRP materials in concrete structures.