Round robin testing initiative for fiber reinforced polymer (FRP) reinforcement

An international Round Robin Testing (RRT) programme on FRP reinforcement was conducted within the framework of the Marie Curie Research Training Network, ENCORE, and with the support of Task Group 9.3 of the International Federation for Structural Concrete (fib). Eleven laboratories and six manufacturers and suppliers participated in this exercise. As part of this extensive experimental endeavour, one or more of the following tests were performed by the participating laboratories: 1) tensile tests on FRP bars and strips; 2) tensile tests on FRP laminates; 3) double bond shear tests on FRP laminates (Externally Bonded Reinforcement, EBR) and FRP bars/strip (Near Surface Mounted reinforcement, NSM). This paper will discusses the results of the RRT initiative, among which the experimental results of bond tests on concrete specimens strengthened with EBR and NSM FRP

Strain Measurement Using Embedded Fiber Bragg Grating Sensors Inside an Anchored Carbon Fiber Polymer Reinforcement Prestressing Rod for Structural Monitoring

Results are reported from a study carried out using a series of Bragg grating-based optical fiber sensors written into a very short length (60 mm) optical fiber network and integrated into carbon fiber polymer reinforcement (CFPR) rod. Such rods are used as reinforcements in concrete structures and in tests were subjected to strain through a series of cycles of pulling tests, with applied forces of up to 30 kN. The results show that effective strain measurements can be obtained from the different sensors mounted along the rod. Additionally, the tests show that close agreement with the results obtained from the calibrated force applied by the pulling machine and from a conventional resistive strain gauge mounted on the rod itself is obtained. Calculations from strain to shear stress show a relatively uniform stress distribution along the bar anchor used. The results give confidence to results from various methods of in situ monitoring of strains on such CFRP rods when used in different engineering structures

Non-iterative moment capacities of complex composite beams using Fourier series

A generic procedure is formulated for the determination of the moment capacity of composite beams having a complex cross-section. The key feature is the use of Fourier series to convert the piecewise functions of the cross-sectional stress distribution into a single-rule function. This eliminates the need for several capacity expressions to cover different stress stages, since the procedure permits the use of the general moment capacity expression. It also eliminates any iteration process when determining the location of the neutral axis since equilibrium of the cross-section can be satisfied explicitly. Numerical examples are given to demonstrate the validation and the applications of the formulation.</p

Bond of FRP strengthening systems for concrete structures: a round Robin test

Although various test methods to examine the local bond behaviour of FRP strengthening systems to concrete have been proposed thus far, their implementation can lead to a wide range of results and a standard methodology has yet to be generally accepted. With these issues in mind, a Round Robin Testing (RRT) programme was carried out to assess the performance and reliability of small scale testing on various FRP strengthening systems, including both externally bonded laminates and near surface mounted reinforcement. Ten laboratories and eight manufacturers and suppliers participated in this extensive international exercise, which was initiated within the framework of the European funded Marie Curie Research Training Network, EN-CORE, with the support of Task Group 9.3 of the International Federation for Structural Concrete (fib). This paper describes the proposed testing programme and summarized some of the results obtained by the participating laboratories