Civil Engineering Reference
In-Depth Information
a
C
a
b
w
e
b
FIGURE 5.25
Schematic of generalized equivalent uniform loads for design live load shear,
V
LL
, bending moment,
M
LL
, and floorbeam reaction,
R
LL
.
(sometimes referred to as Steinman's charts) are available in many early bridge design
handbooks, manuals, and texts, for example (Grinter, 1942).
5.2.1.3.6 Shear Force and Bending Moment at any Location in Simply
Supported Spans [with Concentrated Moving Loads Applied
at Panel Points in the Superstructure (Figure 5.26)]
Theareaundertheshearinfluencelinein
Figure5.26
is
[
(a
+
b)(n
R
/n)
]
/
2.Therefore,
the equivalent uniform load for Cooper's live load shear is
V
LL
2
n
(a
.
w
ev
=
(5.30)
+
b)n
R
From Equation 5.17
s
p
n
R
2[
(n
L
/n
R
)
+
a
=
(5.31)
1]
and from Figure 5.26
b
=
n
R
s
p
,
(5.32)
where
n
is the number of panels (
n
4 in Figure 5.26),
n
L
is the number of panels left
of the panel under consideration (
n
L
=
=
1 in Figure 5.26),
n
R
is the number of panels
right of panel under consideration (
n
R
=
2 in Figure 5.26), and
s
p
is the uniform panel
spacing (
s
p
=
L/
4 in Figure 5.26).
Substitution of Equations 5.31 and 5.32 into 5.30 yields
L/n
=
V
LL
2
s
p
ab
.
w
ev
=
(5.33)
