122 TOWERS AND TANKS FOR WATER-WORKS. 



From the summation of the Z components, 



W 

 2S.+-~ 



W 



- 

 *~ 8' 



which is the vertical shear in the girder at the sections to the 

 left of A and C. 



Let G be the centre of gravity of the load on the half-girder. 



The distance OG is , in which r is the radius of the girder. 



W 



For determining moments the load on the half-girder, , will 



be considered as acting at G. 



MX and MZ are indeterminate from the conditions given, 

 but from other considerations it can be shown that 



and M z = o. 



My is determinate. 



'W 2f\ IW 



My = ( - 

 2 \4 



which is the bending moment in the girder at A and at C. 



