THE STORAGE OF GAS
639
DETERMINATION OF MAXIMUM SHEAR
Consider a braced cantilever as in Fig. 390.
Bending moment = WL, and this is resisted by ErZ.
(taking moments about support)
. ■ . WL = ~Rd,
WL
or, R (which is horizontal shearing force at flange) = ,
(v
or, horizontal shearing force =
Bending moment
Depth of gir der
The section we have to consider is a braced cantilever of cylindrical form, i.e. with. no actual top and bottom flanges. Now the radius of gyration of a hollow
cylinder about a pole passing through its centre is 0-707 D. Sir Benjamin Baker assumed, there-fore, that if the guide-framing was considered as an ordinary two-flanged girder the two imaginary flanges might be taken as occurring at the radius of gyration. F. S. Crippps, however, whose conclusions on matters relating to holders are accepted as final, states that, taking all things into consideration, the depth of the imaginary girder may be considered as f of the diameter of the cylinder, i.e. 0-75 of the diameter of the holder, i.e. J D.
Then we have an assumption such as
girder being f D.
It has been shown above
Fig. 390.
shown in Fig. 390, the depth. of our
q . . . , Bending moment
that horizontal shear = ----, ----
Depth. ot guder
But it has already been shown that in the case of the holder framing (see page 633) the total bending moment is equal to—
/ D3\
(\8 L2D + —j 4- 2240 ton-inches,
and the depth of the girder = f D.
. • . Total horizontal shearing force
/ D3\
i 8L2D+ 2 V 2240
X O y
= Td •