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to each pier. Then (lie stress in any main diiigoiml of the left-hand half of tlio 
“tlge ia to be found by commencing at the rigtt-liand end, and adding the numbers 
at the panel points until the loot of the diagonal consklcred is reached, multiplying 
山 6 si ™ by 1 W sec 0, and to tlie product adding the number of panel dead loads 
between the central plane and the panel point at the foot of the diagonal considered 
(including the one at this point) multiplied by Wi soc 0, 
For instance, in a ten- pan cl bridge, tlie stress in tlie end main diagonal, tlio 
number at its foot being eight, will be 
(1+2 + 3 + etc. . . . + 8)- W ~~- + {i + l + l + l)W l sec 0. 
Th e stress iu a counter on the right- hand half of the bridge will be found by 
adding tlio numbers at the panel points until the foot of the counter considorod is 
leached, multiplying the sum by TF sec Q, and from tlie product subtracting tlio 
^ead-load stress of the main diagonal which crosses tlie counter. Thus, in tlio ten- 
pauel bridge, tlie stress in the second counter from tbe centre iu tlie riglit-liand half 
of the spans, or tlie one at the foot of tlie third panel point, is 
(1 + 2 + 3)-^^ g - (Hl)^isec e. 
The greatest stress in any post of a through or pony truss bridge is found by 
adding I ド , to tbe vertical component of the greatest stress in the main diagonal 
attached to Us upper end, or ^ W + W f in caso of a deck bridge, thus in the as- 
sumed bridge, which may bo taken as a through ouo, the stress in tlie 
1 他 tlie left-hand cud, or tlio one at tlio eighth panel point, is 
(1 + 2 + 3+ etc + 7 斤 + (* + 1 + 1) W t + W / 
F or tlie case of a middle post, the stress in one of the counters at tlie upper 
end must be substituted for that of the main diagonal ; thus, in the same bridge, 
t le stress in tlie middle post is 
(14-2 + 3 + 4)-^- i W 1 +W ， . 
The stresses in tlie chords are to be found by the following method : 一 
Pass a plane through tlio foot of the post at or nearest to the middle of tlio 
iiiss, aiul take tlio centre of moments at this foot. From tlie moment of tlio re- 
a ction at the nearest end of the bridge subtract tlie sum of tlie moments of tlie 
loads (TP') lying between the centre of moments and this end, and divide tbe 
1 lienee by the depth of the truss. Tlio result will be tlie stress in the panel of tlie 
0 P c ] 101 d nearest the centre of the bridge : it will be some multiple of W ff tan 0* 
奶 1(3 stress in the panel of the bottom chord immediately below will be equal to 
o one found, loss tlie horizontal component of tlie main diagonal of tLo panel, when 
