Civil Engineering Reference
In-Depth Information
B
C
A
D
s
p
L
n
R
/
n
n
L
/
n
Shear in panel BC
d
1
FIGURE 5.6
Influence line for shear in panel BC for concentrated moving loads applied to
the superstructure at transverse members.
is the number of panels right of panel BC.
(n
R
/n
L
)s
p
s
p
n
R
2
((n
R
/n
L
)
d
1
=
(n
R
/n
L
))
=
1
)
,
(5.17)
(
1
+
+
L
=
n(s
p
)
=
(n
L
+
n
R
+
1
)(s
p
)
.
5.2.1.2.1.3 MaximumBendingMoment(withLoadsAppliedDirectlytothe
Superstructure)
The influence lines for bending at location C and at the center
of the simple span are shown in
Figure 5.7.
They are developed by determining the
bendingmomentatlocationCandatthecenterspanwithaunitloadplacedatlocations
A, B, and C.
5.2.1.2.1.4 Maximum Bending Moment (with Loads Applied to the
Superstructure by Transverse Members)
The influence lines for moment in
panel BC (at distance
d
2
from B) and at location C of the simple span are shown in
Figure 5.8.
They are developed by determining the bending moments at locations B
and C with a unit load placed at locations A, B, C, and D. As shown in Figure 5.8,
a reduction in bending moment occurs for superstructures loaded through transverse
members.
5.2.1.2.1.5 Maximum Floorbeam Reactions for Loads on Simply Supported
Stringers
The influence line for floorbeam reaction at location C assuming simply
supported stringer spans is shown in
Figure 5.9.
It is developed by determining the
shear forces at locations B, C, and D with a unit load placed at locations B, C, and D.
Since stringer spans are generally relatively short, the location of concentrated loads
for maximum floorbeam reaction is usually quite obvious by inspection.