EFFECTIVENESS FACTOR OF CONCRETE IN CONTINUOUS DEEP BEAMS

The authors present an upper-bound analysis of continuous reinforced-concrete deep beams. The concrete is assumed as a rigid-perfectly plastic material obeying the modified Coulomb failure criteria with zero tension cutoff. Two failure modes are examined, each idealized as an assemblage of rigid blocks moving in plane, separated by yield zones. These zones are idealized as lines, the limiting case of narrow zones of failing material undergoing very high strains. The value of the effectiveness factor for concrete in compression for this type of structure is obtained from calibration of the calculated failure loads against the experimental failure loads for 20 test beams. The effectiveness factor can vary with the concrete strength and the amount of web reinforcement, but this provides little improvement over the adoption of a uniform value. The effect of the horizontal and vertical web reinforcement on the load capacity is mainly influenced by the shear span to depth ratio. The deeper the beam, the less effective the vertical web reinforcement and the more effective the horizontal web reinforcement.

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  • English

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  • Accession Number: 00716527
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 25 1996 12:00AM