388 CHAIN BRIDGE, 



The weight supported as given above is only 

 what is borne at one end of the bridge : the 

 whole load which the bridge would sustain, 

 including its own weight, is therefore double 

 the quantity above or 223 tons. It appears 

 likewise that the piers would then be drawn 

 toward each other with a force of 332 tons, 

 and this acting at the end of a lever, whose 

 length is ck, the distance from the top of the 

 chain to the bottom of the river. 



The inclination of the side chain is 33*^. 10'*, 

 and it must sustain the horizontal force of 332 tons 

 as above; therefore, force in ca x cos. 33^. 

 10' = 332; and since cos. 33°. 10' - . 837, 



332 



.'. force in ca z= ::^ ~ 396.6 tons = tension of 

 side chain. 



Resolving this last into its vertical effect gives 

 396.6 X sin. 33°. 10' =i 396.6 x . 547 z: 216.9 tons = vertical 

 pressure from side chain. 



If to this last quantity be added the vertical 

 pressure from the catenary, or 111.6 as found 

 above, we have 216.9 + 111.6 = 328.5 tons = 

 whole force in cf = tension of vertical link. 

 This is borne equally by the two pillars on one 

 side of the river, therefore, weight borne by one 



* The angles of the side chains with the horizon are 33®. 

 30' and 32°. 50' : mean = 33^. 10'. 



