« AnteriorContinuar »
In districts of country where stones abound, walls are the best fences: they require less land than hedges, and, when properly built, give a very neat and finished appearance to a road.
The manner of constructing these fence walls will be described in the chapter on road masonry. Where a quick fence is to be raised, the following specification points out every thing that is requisite: —
"A ditch is to be cut and a bank raised, together occupying a space of eight feet in breadth; the ditch is to be on the field side of the bank, to be cut out of the natural ground, four feet wide at top, ten inches wide at bottom, and two feet and a half deep.* The bank is to be four feet wide, and is to be raised by sods, with the green or swarded side out, to the height of fourteen inches above the side channels of the road.
"Two rows of quicks are to be planted on the ditch side of the bank, a bed being first formed for them, of good vegetable mould, fifteen inches deep, and eighteen inches wide. There are to be twelve plants set in every lineal yard: they are to have
* Where the soil is clay the drain should be four feet deep.
good roots, three years transplanted from the quick bed, and of a strong and healthy appearance.
"These quicksets are to be protected by two rows of posts and rails; three rails in each row: the posts to be of good oak, five feet long, five inches deep by three inches wide, with large buts sunk two feet in the ground.
"The rails are not to be more than eight feet long; to be three inches and a half wide by an inch and a half deep, of good elm, oak, or ash timber.
"In each length of rails two centre posts, at least two inches wide by an inch and a half thick, are to be driven into the ground, and fastened to the rails with strong nails.
"Through cuttings, instead of the ditch and mound as before described, a mound is to be raised on each side for the quicks, eighteen inches high, two feet wide at top, and faced with sod on both sides; outlets for the water which collects behind the mound from the slopes are to be formed under it, at intervals of twenty yards.
"The mound to be composed of the best vegetable mould that can be procured.
"The quicks are to be planted in the centre of this mound."
A quick fence may be also raised in the following manner, in dry soils, without any ditch : —
"A border or flat mound, four feet in width, is to be raised on each side of the road: it is to be six inches above the footpath, and twelve inches above the side channels of the road, if there is no footpath. The top of the mound next the fields is to be made with good earth two feet wide, and to the depth of fifteen inches: two rows of quicksets, twelve in each lineal yard, are to be set in the middle of these two feet."
"These quicksets are to be protected by two rows of posts and rails, as before described."
Where timber is scarce, quick fences may be raised in the following manner: —
"A ditch is to be cut five feet wide at top, and eighteen inches at bottom, and four feet deep; the sods where the land is grass to be laid two feet high above the side channels of the road, and the earth taken out of the ditch to be formed into a bank five feet wide, sloped to a breadth of eighteen inches; to be four feet high; two rows of quicksets to be planted on the outward face of the bank towards the field, in the natural soil on the face of the bank."
When a road is formed on a high embankment, a fence may be made according to the following specification :—
"A wall is to be built on each side of the road thirty feet apart, eighteen inches thick at the foundation, and fifteen inches at the top, two feet high above the side channels, and nine inches deep below them; in all, two feet nine inches.
"The stones are to be laid in neat level courses, closely jointed and well bonded on both sides, and to be of a kind that will not decompose by the weather.
"The length of the top stones to be the thickness of the wall, viz. fifteen inches, and from five to six inches deep, to serve as a coping. A mound of earth twenty inches high is to be raised above the wall, with two lines of sods in the front. One row of quicksets, of twelve in each yard, to be planted on the mound. A single rail fence is to made to protect the quicksets: the top of the rail is to be fourteen inches above the mound."
Wherever a road is carried through a deep cutting walls should be built for the road fences, if stones can be procured.
All road fences should be kept as low as possible, in order that they may not intercept the sun and wind, and diminish their effect in producing evaporation.
For this reason, in deep cuttings, the quicks should never be planted at the top of the banks; but always low down, near the side of the road.
All quick hedges along the sides of roads should be clipped every year in the months of August or September. They should be trimmed so as to be perfectly level at the top, and with a regular and even surface on the side next the road.
To ensure regularity in the appearance of the hedges, a line and templet should be made use of in trimming them.
In constructing roads, masonry is used in a great many cases, and too much pains cannot be taken to have it perfect both in plan and execution.
In arranging the plan of a bridge for a road, it should be considered how far it may be made subservient to improve the longitudinal inclination of a road, and save perpendicular height.
When valleys are deep and narrow, they may frequently be passed without great inclinations in the roadway, by selecting a proper position, and building high piers and arches for a bridge, if a stream or river is to be crossed, as is usually the case. On the other hand, when the land on each side of a river is flat, the bridge should be kept low, to avoid an inconvenient ascent to the top of it.
The following are the principal objects, with respect to bridges, which road-makers should have in view, viz.: — 1st, the most eligible situation as regards the direction of the road; 2dly, the proper width for the roadway; 3dly, the inclinations of the roadway over the bridge; and 4thly, the number and span of the arches.