Contribución del refuerzo externo transversal con laminados de polímeros reforzados con fibras a la resistencia a cortante

• Autores: Mireia Pujol Sánchez, Eva Oller Ibars, Antonio R. Marí Bernat
• Localización: Resúmenes de comunicaciones, 2014, ISBN 978-84-89670-80-8, págs. 57-58
• Idioma: español
• Títulos paralelos:
  • Shear strength contribution of the external transversal reinforcement with fiber reinforced polymer laminates
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• Resumen

  • Nowadays, the application of fiber reinforced polymer (FRP) laminates in the repair and strengthening field of reinforced concrete structures is increasingly widespread. Failure mechanisms are well defined in bending, but not in shear even in the case of reinforced concrete. The majority of existing guidelines calculate the ultimate shear force of the strengthened element as the sum of the ultimate shear force of the unstrengthened element and the FRP contribution. However, the FRP may modify the contribution of concrete and transversal steel. Therefore, the interaction between the behavior of all materials should be studied.

    An experimental program of ten beams strengthened in shear with carbon fiber reinforced polymer (CFRP) laminates bonded in a U-shaped configuration has been performed with the aim of identifying the real contribution of the FRP laminates to the shear strength. The T-beams (0.55 m depth) show two longitudinal reinforcement ratios and different configurations of CFRP laminates (discontinuous ρFRP = 0,84 ‰ y ρFRP = 1,6‰; and continuous) with and without anchorage (see Fig.1). Two tests were carried out in each beam with the same span of 3,300 mm in each specimen, and under a shear span of three times the effective depth.

    In most of tests, the premature debonding of the FRP laminates was observed, sometimes for applied loads similar or lower than the ultimate load of the control beams, such as the case with higher discontinuous reinforcement (see Fig. 2 M2Sa and M2Sb). To delay this type of failure, an anchorage system was employed in some tests. Then, percentages of ultimate shear force increments of 9 and 15% were reached.

    Test results confirm that there is a change in the shear resisting mechanisms of the strengthened beams in relation to the unstrengthened beam due to the FRP application.

    The test instrumentation allow us to identify the trends in the concrete, transversal internal steel and FRP reinforcement contribution to the shear strength. It has been observed that the concrete and transversal steel contribution is not equal to the shear strength of the unstrengthened beam.