— 91 — 
丁 夕 2 = wind pressure concentrated at a windward and leeward panel 
point wlien the bridge is empty. 
^ 3 = wind pressure concentrated at a windward and leeward panel 
point when the bridge is loaded. 
W 4 = load transferred from windward panel point to leeward panel 
point, Tvlien the bridge is empty. 
T^ 5 = load transferred from windward panel point to leeward panel 
point, when tlio bridge is loaded. 
W^TV^W^ : reduced panel dead load on windward truss, when 
the bridge is empty. 
JV 7 = rum el load clue to centrifugal force produced by cars : this is 
for convenience supposed to be equally ciiviclecl between the 
panel points of opposite trusses, although this method may 
produce a small increase of stress upon the lateral struts 
above those whicli will actually exist. 
E = panel engine excess on one truss. 
E 1 =j ： panel load clue to centrifugal force produced by engine excess : 
it is concentrated as is JV 7 . 
The first step in calculating stresses is to fill out one of the following 
tables of data 
, . Double Intersection Even Double Intersection Odd 
ingle Interaection. Number of Panels. Number of Panels, 
h = n = n = 
ding. = 
short diag. = 
short diag. 
sec. 0 = 
long diag. = 
long diag. 
tan. 0 = 
sec. a — 
sec. a 
tan. O ' = 
tan. a = 
tan. a 
TV = . 
sec. ß == 
sec. ß 
tan. 0 r = • 
tan. O' 
W r = 
W = 
W = 
IF"= 
Wi = 
w x •= 
IF 2 = 
JV r = 
W = 
w n == 
JV r = 
jy 4 = 
IFo = 
W 2 = 
Ws = 
W , = 
W , = 
w 4 = 
W 4 = 
JV 7 = 
W 5 = 
TV, = 
E = 
w G = 
6 ~ 
