162 LARY BRIDGE. 



sions of the bridge, are as follow, viz. The centre arch 

 is one hundred feet span ; its rise or springing, fourteen 

 feet six inches : the thickness of piers at the springing, 

 ten feet ; their thickness at low water spring tides, fif- 

 teen feet ; at the foundations, nineteen feet ; their height 

 twenty-nine feet. 



The adjoining arches are each 95 feet span; their 

 rise or springing 13 feet 3 inches. The piers, taken 

 as before, 9 feet 6 inches ; 14 feet 6 inches ; and 18 

 feet 6 inches respectively ; their height 29 feet : the 

 side arches 81 feet span; their rise or springing 10 feet 

 6 inches. The abutments at the level of the springing, 

 13 feet 6 inches ; at the level of low water 17 feet; at 

 the foundations 19 feet: their height from the foun- 

 dations to the springing, 28 feet. 



To produce greater stability, the abutments are made 

 to form an arch, \\hich, abutting against the wing and 

 approach walls, acts in opposition to the thrust of the 

 arches of the bridge. 



The arches spring from their piers and abutments 

 about four feet aoove high water of spring tides. Their 

 altitudes correspond with the curve or camber of the 

 bridge between the abutments, which is formed by a 

 radius of 4670 feet. 



The roadway is 24 feet wide within the railings, 500 

 feet in length within the abutments, and in the centre 

 of the bridge 22 feet above high water of spring tides. 



In the width of the roadway each arch has five ribs, 

 equi-distant from each other, and each rib is cast in five 

 pieces they are cast solid, and their cross section is 

 formed thus 



being 2 feet 8 inches in depth at the springing, 2 feet 

 at the apex, and in every part 2 inches thick, with edge 

 flanges to give them lateral strength. 



Cast-iron plates 25 feet long, 2 feet 8 inches 



