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

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.

### Keywords:

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

### Abstract:

*
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.
*