Civil Engineering Reference
In-Depth Information
Fig. 4.7 V
test
-f
Rj
response for each beam (the number of the beam is next to each point)
compressive strength dispersion found in this study and indicates the absence of
fl
ange in
uence.
It seems that these additional reinforcements (types 2, 3, and 4) could have an
fl
in
fl
uence on
ber-only beams without stirrups, although there are not enough data
to con
rm this.
Since the
bers contribution to shear-bearing capacity depends on the ef
ciency
of the
bers, it should be possible to
nd a correlation between the shear strength of
the beams and their concrete
exural residual strength. However, in this experi-
mental campaign the dispersion of the residual strength (see Table
4.2
) did not
show a clear trend (Fig.
4.7
).
Based on these results, when analyzing the parameters in
fl
uencing shear
capacity, concrete residual flexural strength was considered a constant parameter
and was evaluated as the average of the residual strengths obtained from the eight
beams containing
fl
bers. Identical criteria were applied for the concrete compressive
strength.
4.4.3.1 Load-De
fl
ection Response
Figure
4.8
shows the load versus mid span de
fl
ection response for one beam for each
combination of top
ange width and shear reinforcement conditions. The other
beams were eliminated for clarity
fl
ber shear
reinforcement showed a ductile failure with controlled post-peak behavior. All the
others, including the one with stirrups-only and no
'
s sake. The beams with stirrups and
bers, revealed brittle failure with
a sharp drop after the peak. No clear differences in ductility (post-peak behavior)
were observed between the beams reinforced with only
bers or only stirrups.
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