Manufacturers:
x Production of FRP bars as well as that of single phase (fibers and matrix) shall be subjected to a quality control program including fibers, matrices, adhesives, pre-cured composites and other constituents.
x Manufacturers shall provide test certificates for each production lot in compliance with their published literature.
x Whenever possible, each production lot shall be marked to ensure traceability. If this is not the case, each lot shall be accompanied by labels or tags reporting all the information needed for their traceability.
Designer:
x Designers shall clearly state the quality and characteristics (geometrical, mechanical, and physical) of FRP bars, specifying, if necessary, the minimum acceptance requirements. x Designers shall specify the acceptance criteria for FRP bars, informing the construction
manager of the samples to be taken and the tests to be carried out. For example, depending on the relevance of the application, designers could suggest to carry out some tests to check some or all of the mechanical and physical characteristics reported by the manufacturer in the technical data sheets.
Contractor/subcontractors:
x Shall obtain the FRP bars indicated by the designer through suppliers/manufacturers who guarantee the quality of their products.
x Shall make sure that the products are accompanied by suitable technical data sheets, reporting both mechanical and physical characteristics, and possibly by laboratory test certificates.
x Shall make sure that the products comply with the provisions indicated by the designer; if the material with the indicated requirements is not available, they shall agree with the designer upon viable alternatives.
Construction manager:
x Shall make decisions as to the acceptance of products.
x Shall check the compliance of the material with the designer’s provisions.
x Shall check the origin of the supplied material. FRP bars are typically marked by the manufacturer for their identification or they have labels or tags with the necessary information for their traceability.
x Shall check the mechanical and physical characteristics of products using the test certificates provided by the manufacturer.
x Based upon the importance of the application, it may require experimental tests to evaluate both quality of materials and compliance with the values provided by the manufacturer. Such tests shall be carried out in laboratories of proven experience that are appropriately equipped to characterize FRP materials. Acceptance criteria may be based on the maximum acceptable deviation of results from the values obtained during production. In such a case, it is necessary to ensure that the test procedures are the same. In some cases, tests may be required to evaluate both mechanical and physical properties of un-conditioned and conditioned specimens to take into account temperature and moisture variation.
Test laboratories:
x Shall demonstrate experience in the experimental characterization of FRP materials. x Shall be equipped with appropriate measurement devices and tests instrumentation.
x Shall carry out the experimental tests according to the procedures indicated in the specific standards for FRP bars.
x Shall provide detailed test reports on test instrumentation and results.
x Shall own a quality manual and carry out experimental activities according to EN-ISO17025 “General requirements for the competence of testing and calibration laboratories”.
Inspector:
x Check the quality of the materials to be in compliance with the manufacturer specifications. x Verify that all materials used have been accepted by the construction manager.
9 APPENDIX E (CALCULATING DEFLECTIONS AND CRACK
WIDTHS FOR FLEXURAL ELEMENTS OF CONCRETE
REINFORCED WITH FRP BARS)
This section describes the procedure to be used by the manufacturer to determine through appropriate tests the FRP bar-concrete adherence in order to accurately evaluate deflections and crack widths, as previously set out in Sections 4.7.3.3 and 4.7.3.4.
Deflections can be calculated using the following formula:
m m cr cr 1 2 max max 1 ª º § · § · « » ¨ ¸ ¨ ¸ « » © ¹ ¬ © ¹ ¼ M M f f f M M , (7.1)
with the quantities already having been defined in Section 4.7.3.3.
On the basis of a population of at least five elements of concrete reinforced with FRP bars, that shall be subjected to four-points bending test, deflections and crack width are measured for fixed load values, ensuring that for a single test at least five acquisitions are made over time intervals between 20% and 60% of the ultimate load.
The same load values are used to calculate the theoretical deflections starting from Equation (7.1). The exponent, m, is determined on the basis of the comparison between the analytical and experimental results, using an appropriate statistical analysis (i.e one based on the maximum likelihood method).
Upon determining this value, the experimental values of the crack widths for the tested specimens are then compared with the corresponding theoretical values, computed according to Equation (4.9) and assuming the m value obtained for the previously mentioned procedure assigned to it as well as to the coefficients E1 and E2 the unitary value.
The coefficient, k1, as obtained from Equation (4.10), is determined through an appropriate
10 ACKNOWLEDGEMENTS
This document has been translated verbatim from Italian with the support of Department of Civil Engineering of University of Salerno (DICIV) and the Center of Excellence on Structural Composites for Innovative Construction (SCIC).
The translation has been carried out by the members of the Task Group under the supervision of Raffaello Fico, Renato Parretti, Andrea Prota (SCIC) and Valentino Paolo Berardi (DICIV), whose contribution is gratefully acknowledged.
The members of the Task Group thank all the practitioners, industries, and academia that have worked in order to achieve the general consensus on the present document.