一 159 — 
diametei. is 32.6 5, and the corresponding intensity from Table VIII for two fixed 
euds is 2.889 tons. Dividing this into 84.628 gives 29.29 square inches as the 
section required. 
• Subtracting from this 7.5 square inches and multiplying the remainder by ten 
81x ^ ls gives 86.82 pounds as the weight per foot of each clmimel. 
Next let us proportion the posts. 
Assuming 12" channels for the end ones, makes the ratio of length to least 
^lameter 25, for which Tabic YIII. gives for two hinged ends an intensity of 2.71 tons, 
us divided into 87.122 gives 13.7 as the sectional area of the two cluimiels. 
ultiplyiug by ten anti clividing by six gives 22.83 pounds per foot as tlie weight 
eacli channel. Consulting Carnegie's cliaunel sections in Chapter II., we find that 
hls sectio » is obtainable. 
k ) ^ SSUm * u o ten inch chaunels for the next post makes tlie ratio 80, the intensity 
T the section vequirecl 9.93 □’’， corresponding to two 16.55 pound channels. 
'vill be 
necessary, however, to use 17.5 pound channels, for the Union lion Mills 
nothing between this and 1G pound channels. Let us assume six inch channels 
7 le post, making the ratio 50, tlie intensity 1.256 and the section required 
s 口 ,， corre8 pondiiig to two 18.22 pound channels. Tliis is not an economical 
• 10n, 80 let us try seven inch cliamiels, making the ratio 42.86, the intensity 1.565 
the section required 0.87 □ パ , corresponding to two 10.62 pound channels, wliicli 
ud from Chapter II. are obtainable. 
to P し now time to look to the chord packing and see that tlie assumed width of 
tht V° 1 ^ Plate わ sufficient, yet not too great. Referring to Tablo VII. we find that 
^ e Slze of the beam hangers is 1A" square. From Table XVI. we find the width of 
prod 6 f ° r & W 一 45 •* channel is about 3.1" doubling which and subtracting the 
Kh IT む 0111 20" leaves 13.8 ノ Tlie area of bhe top chord inner connecting plate 
1 〇 ず . （ e a little more than half tlie area of one chanuel say 7 口 ", which divided by 
this ; フ 8 ft b ou t 0*6 say I" or 0.68" as tlie necessary tliicknoss. Subtracting twice 
12 ^ 2 ^ 1U 13.8 and allowing a clearance of i r/ for the post inside tlie chord will leave 
thick 邮 如 di s t aüce between pinner faces of post cliaunels. Allowing for tlie 
8 l)ace 郎 8 。ざ [I】 6 plate は the foot of the post will leave 11.42 ^ as the clear packing 
the cl 1 以 〇 mus t go four main diagonals each 1 ,( thick, two beam hangers and 
6.68" 肌 6 sum of the thicknesses of tlie diagomik and beam hangers is 
4.29" f 0 adding そ " for clearance and subtracting the sum fi.om 11.42 leaves 
plates 的 山 〇 咖此 As the latter should be about square, and as the connecting 
"will b 〇 二 1 / 山 6 ou t s id e should be half an iiioli thick, the space required by tlie strut 
; ’’ showing clearly that this arrangement will not suit. 
^idcl] 1Gle U0 reason w hy wg should not pack tlie main diagonals outside of the 
next 6 1) 〇 8 も ’ ^^i*efore we will do so, and obtnin i f, more room. At the foot of tlie 
side of こ 】 ere わ .l ns ^ room enougli, for two main diagonals go inside and two out- 
Sam, 、 16 り 0 “， au d the counter passes between the chord strut channels. Tlie 
the u lemai 】、 s a PP^y to the feet of the end posts, and as there is abundant room at 
l ^ght ^ ^ ei l〕 aue l Points and at tlie shoe, we see that the assumed width of 20" is ju&t 
