SENSITIVITY OF SHEAR STRENGTH OF REINFORCED CONCRETE AND PRESTRESSED CONCRETE BEAMS TO SHEAR FRICTION AND CONCRETE SOFTENING ACCORDING TO MODIFIED COMPRESSION FIELD THEORY

The modified compression field theory (MCFT) is used to study the effect of shear friction and biaxial softening on the computed shear strength of reinforced concrete (RC) or prestressed concrete (PC) beams. A comparison is presented of the various relationships that have been proposed to represent the shear friction behavior of cracked reinforced concrete. A decrease in shear friction within the range of experimental data as found, for example, in high-strength concrete, can lower the shear strength of beams with minimum shear reinforcement by 15-25%, according to the MCFT. In addition, a comparison is presented of different relationships used to represent the biaxial compression-tension strength of reinforced concrete for RC and PC beams. Some theories of biaxial softening of concrete do not predict concrete crushing even for very high deformations, but rather show significant shear force gain after stirrup yielding and crack slipping. For an RC beam, some theories predict shear tension failure while others predict diagonal compression failure. However, the first peaks of shear load, which occur close to stirrup yielding and crack slipping, are within 10% of one another for the various theories and within 10% of the test value for the PC beam.

Language

  • English

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Filing Info

  • Accession Number: 00767725
  • Record Type: Publication
  • Contract Numbers: BCS-8820502
  • Files: TRIS
  • Created Date: Aug 3 1999 12:00AM