Formwork for Concrete Structures by R.L.Peurifoy and G.D- By EasyEngineering.net

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Design of Wood Members for Formwork 111
FIGURE 5-10
Multiple-span beam with uniformly distributed loads.
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Deflection of Multiple-Span Beams with Uniformly
Distributed Loads
Figure 5-10 shows a uniformly loaded beam extending over several
supports, such as studs supporting sheathing or joists supporting
decking. The approximate value of maximum deflection in the end
spans will be as shown in Eq. (5-28).
For multiple-span beams; ∆ =wl 4 /1,743EI (5-28)
The uniform load that will produce a deflection equal to ∆ will be
as follows:
For multiple-span beams; w = 1,743EI∆/l 4 (5-29)
For ∆ =l/270, w = 1,743EI/270l 3
For ∆ =l/360, w = 1,743EI/360l 3
For ∆ = ¹⁄8 in., w = 1,743EI/40l 4
For ∆ = ¹⁄16 in., w = 1,743EI/80l 4
(5-29a)
(5-29b)
(5-29c)
(5-29d)
Table for Bending Moment, Shear, and Deflection
for Beams
As illustrated in the preceding sections, there are many combinations
of loads and locations of loads on beams used in formwork. Numerous
books are available that provide the maximum bending moment,
shear, and deflection for various applications of load, combinations
of loads, span lengths, and end conditions.
There are several methods of analysis that can be used to determine
the maximum shear force, bending moment, and deflection in beams.
For complicated forming systems, it may be necessary to provide a precise
analysis of the structural members, including shear and moment
diagrams, to determine the appropriate values of shear and moment.
Table 5-2 gives the maximum bending moment, shear, and deflection
for beams subjected to the indicated load and support conditions.
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