Civil Engineering Reference
In-Depth Information
8.2 Data Selection
In total, 215 structural elements were used to prepare a complete database to
analyze the shear behavior and the in
uence of each parameter on shear out of 363
elements of the experimental database. As can be seen, 148 elements were elimi-
nated for various reasons. In particular, the following data were removed:
fl
1.
those with different failure modes to shear;
2.
those beams which are not known in some detail;
3.
ber type;
4. those which are not available any value of strength; and,
5. all those elements with ratios a/d smaller than 2.5, in which arching action is
dominant [
1
the beams containing a mixture of more than one
4
].
-
The present database was made by using elements from other databases (as
performed by the University of Brescia (Italy) and RILEM databases), plus all the
elements tested in shear in the Brite/Euram project [
5
], beams tested by Dupont and
Vandewalle [
6
], other beams [
7
] as well as the elements tested within the present
PhD thesis.
The input parameters used were: the shear span-to-depth ratio (a/d); the effective
depth (d); the concrete cylinder compressive strength (f
c
); the residual
exural
tensile strength (f
R3
) corresponding to a crack mouth opening displacement
CMOD = 2.5 mm, according to the Standard EN 14651 [
8
]; the reinforcement ratio
for longitudinal reinforcement (
fl
ρ
l
); the average stress acting on the concrete cross-
section for an axial force due to prestressing actions (
bers
(kg/m
3
) and transverse reinforcement area per unit length (A
s
ʱ
/s). The output value
is the safety margin (SM) obtained as V
test
/V
theo
(the shear test value divided by the
shear theoretical value).
A large shear database has been obtained, that covers a great interval of the main
parameters in
˃
c
); the amount of steel
uencing shear. Table
8.1
summarizes the ranges of the different
values used in this shear database.
The theoretical shear (V
theo
) was calculated for each of the beams according to three
structural Codes: the Spanish Standard EHE08 [
9
], the RILEM approach [
10
] and the
Final Draft of Model Code 2010 [
11
]. In this chapter, the limitations to the parameters
according to the Codes (see Table
5.2
in the introduction to Part III) were applied.
fl
Table 8.1
Range of
parameters in the complete
database (N = 215 elements)
Parameter
Minimum
Maximum
d (mm)
102
1,440
a/d
2.50
4.69
f
cm
(MPa)
17
96.34
f
R3
(MPa)
0
10.60
Amount of
bers (kg/m
3
)
0
240
ρ
(%)
0.41
5.82
˃
c
(MPa)
0
12
A
s
ʱ
/s (cm
2
/m)
0
4.90
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