Civil Engineering Reference
In-Depth Information
Figure 8.5
Equilibrium within a beam element B (uniformly distributed load on top surface)
two shear forces can be resolved into a diagonal compressive force in the concrete struts and
a vertical tensile force of 0
.
9
w
s
in the stirrup. Summing the two vertical forces in the stirrup
on the top face gives 0
.
9
w
s
−
w
s
=−
0
.
1
w
s
. On the bottom face, however, the sum of the
two vertical forces is 0
s
, which is different from the top face.
If we observe the equilibrium of the five subelements of the extreme right column in Figure
8.5, it can be seen that the stirrup forces due to
.
9
w
s
−
0
.
8
w
s
=
0
.
1
w
w
on the top faces increase linearly downward
in the following sequence:
−
0
.
1
w
s
,0
.
1
w
s
.0
.
3
w
s
,0
.
5
w
s
and 0
.
7
w
s
. The stirrup forces on
the bottom faces increase linearly downward in the sequence of 0
.
1
w
s
,0
.
3
w
s
,0
.
5
w
s
,0
.
7
w
s
and 0
s
.
If we also look at the top faces of the top five subelements, the stirrup forces due to
.
9
w
w
increase from right to left in the following sequence:
−
0
.
9
w
s
.
−
0
.
7
w
s
,
−
0
.
5
w
s
,
−
0
.
3
w
s
and
−
0
.
1
w
s
. Similarly, the sequence of stirrup forces,
−
0
.
7
w
s
,
−
0
.
5
w
s
,
−
0
.
3
w
s
,
−
0
.
1
w
s
and 0
.
1
w
s
, can be observed on the bottom faces of the five extreme left subelements from
