Chap. VIII.
BRITAIN.
469
fall of the roadway over the bridge should not exceed one in twenty-four in the steepestplaces.
“ 'I*he roadway to be formed of properly cleansed gravel to cover the top of the arch atleast 14 inches.
“ Each bridge of one arch to be built so that the parapets when finished should have acurve horizontally of not less than 3 feet in 36 feet in length ; and all the bridges to battervertically at least 1 foot in 12 of height, and this height also to have a concave curve of4 inches.
Span ofArch.
Rise ofArch.
Depth ofArch Stones.
Height ofAbutments from lied ofRiver to theSpringing.
Thickness ofthe W alb. ofthe Abut-ments on anAverage.
Length ofParapets fromthe Face ofAbutmentswith Wingsunder.
Height ofParapetsal>ove theCrown of theArch.
Thickness ofSnandrilUandWings on anAverage.
Thickness ofthe invertedArch.
Ft.
In.
Ft.
In.
Ft.
In.
Ft.
In.
Ft.
In.
Ft.
In.
Fu
In.
Ft.
In.
Ft.
In.
4
0
1
6-
1
0
2
6
1
6
9
0
1
2
1
6
0
9
6
0
2
0
1
o
o
6
2
0
10
0
2
2
1
6
I
0
8
0
3
0
1
o
2
6
2
0
12
0
3
2
2
0
1
0
10
0
3
6
1
3
3
0
2
6
12
0
3
2
2
0
I
0
12
0
4
0
1
4
3
0
3
0
14
0
3
2
2
6
1
0
18
0
6
0
1
6
3
0
4
6
18
0
3
2
o
9
1
4
24
0
8
0
1
9
4
0
5
0
24
0
4
2
2
9
1
4
30
0
12
0
2
0
4
0
5
6
30
0
4
2
3
0
1
6
50
0
15
0
2
6
6
0
6
6
116
0
4
8
3
6
l
6
“ The spaydrills were all to be filled up between the outside walls with solid masonry,above the level of the springing of the arches, up to one-third of the height of the rise ofthe arches.”
Dunheld Bridge, erected in 1809, has five large arches, and two smaller ones. Themiddle arch is 90 feet span, with a rise of 30 feet; the two adjoining arches are 84 feet span,and the other two 74 feet; the two smaller or land arches being only 20 feet span. Thebreadth, measured across the soflite of the arch, is 27 feet, that of the roadway between theparapets 25 feet. The thickness of each of the two middle piers is 16 feet, that of thetwo next 14 feet, and that of each of the two side piers 20 feet, and of the land abutments7 feet. The cost of this bridge was 13,361/.
Allness Bridge , on the Fearn Road, county of Ross, has one stone arch of 60 feet spanand 20 feet rise.
Helmsdale Bridge, on the Dunrobin road, Sutherland, has two stone arches, each 70 feetspan, with a rise of 25 feet.
Conan Bridge, near the town of Dingwall, consists of five arches of 65 feet, two of 55 feet,and two of 45 feet span. The cost was 6,854/., and the water-way 265 feet.
Poturch Bridge , over the River Dee, near Kincardine O’Neal, has three arches, themiddle spanning 70 feet, the others 60 feet.
Lovat Bridge has five arches, the middle spanning 60 feet, two 50 feet, and two others40 feet, the cost of which was 8802/. ; the water-way 240 feet.
Ballater Bridge, over the Dee, has five arches, the middle one spanning 60 feet, and thetotal water-way being 2S8 feet. The cost was 4224/.
Alford Bridge lias three arches, the middle arch spanning 48 feet, the others 40 feet; thewhole water-way being 128 feet, and the cost 2000/.
Fairness Bridge lias three arcltes, the middle spanning 55 feet, the other two 36 feet,the total water-way being 127 feet; the cost was 1255/. These were all erected bv Mr.Telford.
Bridge at Edinburgh , over the valley of the North Loch, was built by Mr. Mylne, andconsists of three arches each 72 feet span, and two smaller 20 feet span. The heightfrom the surface of the ground to the springing of the arches is 17 feet 6 inches; thearches are semicircular, and the thickness of the voussoirs 2 feet 9 inches. From the top ofthe voussoirs to the top of the parapet is 9 feet 9 inches, making the entire height 65 feet.The breadth across the soffite of the arches is 42 feet 3 inches. The cornice and parapetcurve downwards, which produces a bad effect.
Bridge over the Teviott, erected by Mr. Elliot, consists of three arches; the middle spans65 feet, and rises 17 feet: the whole are segments, and the width over the parapets is23 feet, This bridge was completed in 1795.
Peas Bridge, on the road from Berwick to Edinburgh , was designed by David Hender-son ; it has 4 arches, the span of the greatest being 55 feet, and the entire height of thebridge 124 feet; it is constructed over a deep dingle.
Bridge at Fochabers, over the Spey, was built by Mr. G. Burn ; it consists of four arches,the two in the middle span 95 feet, and the breadth over the parapets is 21 feet 6 inches;as the number of arches are here even, a pier occupies the middle of the river.
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