Civil Engineering Reference
In-Depth Information
TABLE E7.15
Shear Flow along the Span
Location
Distance,
x
,
V
r
V
DL2
q
r
q
DL2
q
max
From End
a
(in.)
(kips)
(kips)
(k/in.)
(k/in.)
(k/in.)
A
0
310
40
2.61
0.20
3.70
B
270
220
20
1.85
0.10
2.51
C
540
167
0
1.40
0
1.71
The shear flow due to dead load on the composite section is small and
ignoredinthepracticaldesignofcompositesteelandconcretegirders.Thisis
alsoevidentfromcomparisonoftheallowabledesignloadfortheshearstress
range,
S
r
, and the allowable design load for the maximum shear stress,
S
m
.
π
(
0.875
)
2
4
7.0
S
r
=
=
4.21 kips,
π
(
0.875
)
2
4
20.0
S
m
=
=
12.0 kips.
Use three shear studs across the flange width;
12.63
/
q
LL+I
.
The actual shear stud spacing can be arranged in order that the maximum
overstress is, for example, 10%, as shown in
Figure E7.7.
Design of web plate stiffeners:
Useanglesboltedtothewebinordertoprecludeissuesrelatedtowelding
at the base of transverse stiffeners. Use a single 6
×
4
×
1
/
2 angle at 67.5 in.
centers as shown in Example 7.1.
Design of bearing stiffeners: Use four 8
×
4
×
1
/
2 angles as shown in Exam-
ple 7.1.
Serviceability—deflection criteria
The required gross moment of inertia for a LL+I deflection criteria of
L/f
Δ
is (see Chapter 5)
7314
(
90
)f
M
LL+I
Lf
Δ
Δ
in.
4
I
≥
≥
≥
340.4
f
Δ
1934
1934
The required section gross moment of inertia for various deflection
criteria,
f
, is shown in
Table E7.17.
Δ
TABLE E7.16
Shear Stud Spacing along the Span
Location
q
r
(k/in.)
s
(in.)
A
2.61
4.9
B
1.85
6.8
C
1.40
9.0
