A theoretical and experimental study of the ultimate strength of the deck slab of composite I-beam bridges is summarized. A theory, based on a mechanical model proposed by Kinnunen and Nylander, for punching failure of simply supported slabs, is developed which permits the calculation of the punching strength of restrained slabs. The theory suggests that a deck slab can be expected to have a high inherent strength due to boundary restraints ensured by the presence of shear connectors, beams, diaphragms and the neighbouring slab areas. One-eighth scale direct models of a 24.4 m (80 ft) span prototype bridge were tested in laboratory studies of both orthotropically and isotropically reinforced slabs. Shear connector behaviour and dead load stresses appropriate to unshored construction were simulated. The results of the tests show that conventionally reinforced deck slabs have very high factors of safety against failure by punching and are wastefully reinforced. From considerations of ultimate strength as well as shrinkage and temperature reinforcement requirements, 0.2 per cent isotropic reinforcement is recommended as being adequate for bridge slabs of the type studied. Although this amounts to approximately 30 per cent of the current reinforcement requirements for such slabs, a high factor of safety can still be expected. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; Photos; References; Tables;
  • Pagination: pp 162-170
  • Monograph Title: Bridge Engineering. Volume 1
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00183760
  • Record Type: Publication
  • ISBN: 0309026962
  • Files: TRIS, TRB
  • Created Date: Dec 3 1978 12:00AM