| Load/deflection conversion formulas |
In the elastic range,
deflection is proportional to the applied load for both uniform and concentrated loads.
This relationship can be used to determine the deflection that any load which is less than
the allowable load will produce, as shown in Example A below. Also, if desired, the load
which will produce a specified deflection can also be determined if the load is in the
elastic range as illustrated in Example B.
EXAMPLE A
What deflection will a 300 lb. concentrated load produce on
a plank (catalog number 103012) spanning 5'0"?
See page 27 for item 103012 at a span
= 5'0"C = 480 lb. D =
D @ 300 lb. = 0.26" x 300 lb. = 0.16"
480 lb.
EXAMPLE B
If a plank (catalog number 103012) is spanning 6'0",
what concentrated load will produce a 1/4" deflection?
See page 27 for item 103012 at a span of 6'0"
C = 400 lb. D = 0,26'
C @ 1/4" = 400 lb. x 0.25' = 385 lb.
0.26"
8-and 10-Diamond allowable load and deflection
tables
As width increases, grating strut flexure
becomes much more important. Eight and 10-Diamond products are wide enough to require a
change in the assumptions used to prepare the 2-through 5-Diamond Product Selection/Design
Tables. No longer will it be assumed that both side channels are equally effective in
supporting a concentrated load. In fact, to provide a high level of safety, one side
channel will be required to carry 100% of a concentrated load.
Also strut deflection for 8- and 10Diamond
products may be significant. The most critical case occurs when a concentrated load is
located at midspan and mid-width. To determine how the struts perform under this loading,
3-ft. long samples of each material and thickness were tested. For these tests the side
channels were continuously supported and loads were applied using a 1-ft. long and 1-in.
wide bar placed. parallel to the side channels at mid-width and at the longitudinal
center.
Results of these tests, included in the 8-
and 10-Diamond Product Design Tables, proved the performance of these materials when a
concentrated load is applied at mid-span and midwidth. If a concentrated load is to be
applied at mid-width at the end of a plank, consult the "strut loading" table.
The following values have been tabulated
for 8- and 10-Diamond grating:
Allowable Uniform Load (U)
Values are given in the rows labeled "U" and are the lowest of the (1) maximum
allowable uniform loads considering channel flexure, and (2) maximum grating surface
flexure.
Deflection Corresponding to
"U"
Deflection values appear in the rows labeled " D", below the " U "
values, and are maximum deflections the allowable uniform loads would produce. Maximum
deflections will occur at mid-span and mid-width and will be the sum of side channel and
grating surface deflections. (Fig. 3).
Allowable Concentrated Load (C)
Values tabulated in the rows labeled "C" are the lowest of the (1) maximum
allowable concentrated load considering side channel flexure (with one side channel
supporting the entire load-Fig. 2), and (2) the maximum allowable strut flexure (Fig. 1).
Deflection Corresponding to
"C"
Deflection values are indicated below the "C" values in the table and are
deflections the allowable concentrated loads will produce at mid-span and at mid-width.
The deflection is the sum of side channel and grating surface deflections.
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