"LE PONT VIERENDEEL. LI. 



Then by equating each of the five columns in the table to zero, 

 the following live equations are arrived at : — 



(n? + I* ) ( P ^ + F 3 + P 4 + P 5 ) + P s f| = 5 W, 

 H D 



XT T\2 



14-5 W x 5l±1 



(^ + Sf) (5 Pi+5 Pa+5 P3+3 p * + Ps) + p * K = 



TT I) 2 

 22-5 ¥, 5_t! 



{tT + K) < 7P ' + 7P <- + »P. + 8P 4 + P.) + Pi-gJ-- 

 28 W™ 



: (^ + S) (9 P + 7 P2 + 5Pa + 3 p * + P8) + Pi s = 



sow, **£* 



From these equations the several values of P x P 2 P 3 P 4 and 

 P 5 can be ascertained. 



As a particular case the Professor has taken a bridge of 31*5 

 metres span, as shown on Fig. 7. It is for a single line of rail- 

 way and the live load is taken as 4,700 kgs. per lineal metre 

 = 1*41 tons per foot ; there are nine bays in the girder, the 

 verticals being placed 3*5 m. apart ; the cross girders are fixed 

 to the top of the verticals ; the weight of the bridge supported 

 ►by the bearings h given as 62,703 kgs. ; the length of each main 

 girder is 32*1 metres and they are spaced 3 metres apart, thus 



62703 x 3*5 

 the dead weight at each vertical = — = 3418 kgs. and 



the live load at each vertical = = 8225 kgs., making 



z 



.a total load of say 11600 kgs. = W. The height of each girder 



