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Shear Strength of PC Beams: Parametric Study of Shear Friction and Concrete Softening.

pdf icon Shear Strength of PC Beams: Parametric Study of Shear Friction and Concrete Softening. (973 K)
Duthinh, D.

High Strength Concrete, First (1st) International Conference. Sponsored by United Engineering Foundation, Inc. American Society of Civil Engineers (ASCE). July 13-18, 1997, Keauhou-Kona, Hawaii, Azizinamini, A.; Darwin, D.; French, C., Editor(s)(s), 280-293 pp, 1997.


concrete beams; biaxial softening; building technology; prestressed concrete; reinforced concretes; shear friction; shear strength


The Modified Compression Field Theory (MCFT) is used to study the effect of shear friction and biaxial softening on the computed shear strength of prestressed concrete (PC) beams. According to the MCFT, a decrease in shear friction within the range of experimental data, as found in high-strength concrete (HCS), can lower the shear strength of beams with minimum shear reinforcement by 15% to 30% depending on the method of estimation. For high levels of shear reinforcement, the effect is minor and may not be of practical significance. In addition, a comparison is presented of different relationships used to represent the biaxial compression-tension strength of reinforced concrete. For 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. However, the first peaks of shear force versus crack width curves, which occur close to stirrup yielding and crack slipping, are within 102%-111% of the experimental shear strength.