The total energy absorbed by a reinforced concrete beam when struck by a hard impactor depends in part on the local energy absorbed both in the contact zone and by the impactor. Tests have therefore been performed on both beam segments and reinforced concrete beams to ascertain the extent to which the local effects in nominally hard impacts affect the total energy absorbed. The beam segments, containing similar concrete and reinforcement to their corresponding beams, were rigidly supported along their length and were impacted by the same solid impactor as that used for the flexural beam tests. An optical technique, in the form of a line-scan camera, and a load-cell under the striker enabled the contact-zone displacement and the transient load during the impact to be fully recorded. Reinforced concrete beams with either plain or fibre concrete, on simple, pinned or fixed supports, have all been included in the test programme to indicate the significance of the energies absorbed in the contact zone and at the supports as a proportion of the total energy absorbed by reinforced plain or fibrous concrete beams subjected to accidental, nominally hard impacts. The energy absorption on initial indentation of the concrete in the contact area is shown to be very small for either plain or fibre concrete. Thus the practical advantage of fibres in the shattered zone is that the fibrous concrete can still hold together under large deformations. A simplified approach for designing reinforced concrete beams for impact by quantifying the energy absorption from the moment-rotation characteristics is outlined and since the total energy absorbed by an impacted beam depends essentially upon the load-deformation behaviour, this approach can also be used as a basis to assess the advantages of using fibre reinforcement in conjunction with conventional bar reinforcement. (A)

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    The Boulevard, Langford Lane
    Kidlington, Oxford  United Kingdom  OX5 1GB
  • Authors:
    • HUGHES, B P
    • AL-DAFIRY, H
  • Publication Date: 1995


  • English

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  • Accession Number: 00720844
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: May 24 1996 12:00AM