—— 92 — 
五 1 = 
i TV sec. 0 = 
JVj sec. 0 = 
\ W l sec. 0 = 
IF"tan. 0 = 
i JF^tan. 0 == 
^ E sec. 0 = 
上 E tan. 0 = 
IFotan. 
1 WM\^ 
Wystan. == 
I W-Mn. O' = 
PF^an. 0 = 
\ JF^an. = 
WV,an • ク = 
^ TF 5 tan. ^ = 
IFotan. 0 = 
i W^tan. ク = 
W^tan. 0' = 
\ IF 7 tan. ダ = 
~~ -Eitan. 0 ’= 
W, 
= 
E 
== 
Ei 
= 
iw 
= 
lw 
sec. 
a 
w, 
sec. 
a 
i W^sec. 
a 
1 ^ 
see. 
ß 
W, 
sec. 
ß 
i W, 
sec. 
ß 
JV ,f tan. a = 
金 W 7 ’’ tan. a = 
—E sec. a — 
E sec. ß — 
4 £； tan. « = 
TF 2 tan • グ = 
i I^tan. ö f = 
W^ 3 tan.ö ， = 
\ I^stan. = 
TF 4 tan.ö = 
\ W 4 tan.O = 
W B tein.O = 
I W 5 ttin % 0 = 
Wq\,hw.O = 
J W G tan.O = 
7 tanW = 
I H 7 7 tan.^ , = 
-士 ^itan.ö' = 
W 7 = 
E = 
7?i = 
= 
— W sec. a : 
■- W^isec. a : 
— IF sec. ß : 
- IF ^ec. ß ■ 
i Wtan. « : 
¥ ^ = 
— £J sec. a 
E sec. ß 
- E sec. a 
^tan. 0 r 
fFgtan. O' 
W ? 4 tan. ^ 
JF 6 tan. ^ 
W^etan. Ö 
]^ 7 tan, 6 r 
E tan. 0 r 
The value of W\ may be taken as \ W x for through bridges, J W\ for pony truss 
bridges and f W\ for deck bridges : in short through spans this causes a small error 
on the side of safety, and in short deck spans a correspondingly small error on the 
side of clanger. For the latter it might be well to make TP = i W\ 
Having filled out the table of data, the next step is to draw a skeleton diagram 
large enough to contain all tho stresses and sections. It is not necessary that the 
diagram be drawn to scale ; but tlie ratio of panel length to depth of truss on the 
diagram, for the sake of appearance, should not vary too greatly from tlie ratio of 
the actual values of these dimensions. A panel length of an inch and a half, aud a 
