Civil Engineering Reference
In-Depth Information
P n
A
B
L /2
L /2
1.0
a
b
FIGURE 5.27 Determination of equivalent uniform loads for floorbeam reaction.
The equivalent uniform load, w ev , for shear (Equation 5.33) and, w em , for bending
moment (Equation 5.36) can be calculated within various panels at location C ( a
b
fromtherightsidein Figure5.26 ) usingthesamechartsplottedforsimplespansshown
in Figure 5.25.
+
5.2.1.3.7 Floorbeam Reaction at any Location in Simply Supported Spans
[with Concentrated Moving Loads Applied at Panel Points (at
Transverse Floorbeams) in the Superstructure (Figure 5.27)]
The area under the shear influence line in Figure 5.27 is ( a
+
b) /2. Therefore, the
equivalent uniform load for Cooper's live load reaction is
V LL 2
(a
.
w eR =
(5.37)
+
b)
The equivalent uniform load, w eR , can be calculated at various floorbeam locations
with adjacent panel lengths a and b as shown in Figure 5.27, using the same charts
plotted for simple spans shown in Figure 5.25.
The generalized equivalent uniform loads presented in Steinman's charts are useful
in the design of usual steel girder and truss railway spans. However, despite the appeal
of ease in design, the use of equivalent uniform live loads has never been prevalent in
Equation 5.33 is of similar form as Equation 5.28.
Equation 5.36 is of similar form as Equation 5.29 with L , b , and s p being constant. If the constants are
included together as K 1 and K 2 , Equation 5.36 is w e = 2 M LL / (a + b)K 1 + (L b a)K 2 and the
similarity with Equation 5.29 is clear.
 
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