2240 x 8 x 1000
W = ---------------, or reducing, W=55308 lbs.
324

[TeX: $W = \frac{2240 \times 8 \times 1000}{324} = 55308$]

Now, these proportions will give ample strength for both flexure and
compression, for if we block the two sticks composing the end brace
together, and firmly connect them by bolts, we shall have a built beam

2240 x 24 x 1000
of 24" x 10"--whence W = ---------------- = 165925 lbs.,
324

[TeX: $W = \frac{2240 \times 24 \times 1000}{324} = 165925$]

and as 134400 lbs. was all that the conditions demand, we really have
an excess of strength. The next set of braces supports the weight of
the rectangle included between the upper ends of the braces and the
two chords, and the dimensions of the sticks are calculated in the
same manner. We find, as we approach the centre of the bridge, that
the strains on the braces become less, and consequently their
scantling should be reduced, but in ordinary practice this is seldom
done.

=Rods.= The next thing is to ascertain the dimensions of the various
tie rods. It is evident that the same weight comes upon the first set
of rods, as on the first set of braces--which will give for the rods
at one end of one truss, 134400 lbs.; and as there are two of these