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ous. If the water is received at the bottom of the trough, and the overflow is taken from near the supply, in a pipe to a culvert, there will be no ice about the trough. The supply-pipe should rise about half an inch above the level of the water in the trough, so as to form a drinking fountain for teamsters and travelers. In the heat of summer, teams will instinctively hurry their pace as they approach these grateful, thirstslaking stations, and their comfort will be promoted to a degree that will well compensate for the outlay. The temperature of water standing in a trough exposed to the sun is more wholesome for working teams than that from cold wells.
The purpose of the bar is to cast the surface water from the road to the side or sides before it has accumulated in such amount as to cut the ruts into gullies. When the surface of the road has a slope to both sides, the bars should be placed opposite each other in the form of an obtuse V. The bottom of the V should be up the grade. There should be no gutter excavated in the road surface on the upper side of the bars, but the bar should be raised slightly above the road surface. No stones or timbers should be used in the bars; good gravel, where obtainable, is the best material. If the bars are placed as near each other as they should be on the heavy grades, the highest portion of the bars, 'that is, at the margins of the road, need not be more than three inches above the level of the surface of the road. On newly constructed roads, whether of broken stone, earth, or gravel, the water bars need frequent and particular attention until they become firm ; in fact there is no por. tion of the road that will give a better return for the required outlay of of labor than the water bars.
A pleasant and durable road for ordinary light country travel may be made on a properly drained foundation, by applying shells to the depth of about eight inches, with a lateral surface grade of a quarter of an inch to the foot, but not sufficiently durable to be profitable for heavy traffic. A few years since, one of the main macadamized turupikes leading out of Baltimore was repaired over a section of about half a mile in length, by dressing the stoned road with shells, applied about six inches in thickness. The solid bed of stones underneath and the heavy traffic on the surface soon ground the shells to powder, and when wet it became a bed of thin lime mortar, two to four inches in depth, which was so objectionable that the company were obliged to scrape up and haul off the whole mass in less than two years after the shells were applied. The circumstances described were particulary unfavorable for shells, as a test of their durability. The wear upon an ordinary carriage road in private grounds is not usually sufficient to reduce the shells to a good road in many years; hence they are not adapted for that use. A shell surface is inclined to rut, and work to the margins, and the shells are very difficult to move so as to repair the road by any hand process; wbile by the use of the grader, they may be readily and rapidly leveled in the construction of a new road, or regraded when displaced by wear. An active inan with a pair of horses, with this implement, will repair two or three miles of shell road in a day, which would require the labor of at least seventy-five men to perform in the same time.
So much depends on the proper condition of the side gutters for the thorough maintenance and protection of the road, that the writer has been induced to give this branch of the subject special attention, and to test a variety of plans, in the hope of arriving at valuable and permanent improvement. Having realized his fullest hopes in one direction, a detailed description of the aim and its results may be given. Finding that the gutters, from the perpetual moisture maintained in them, were inclined to clog with rank, aquatic grasses, le sought to devise a plan to prevent the difficulty. The course pursued was to pave the gutters with boulders, set in about eight inches of washed gravel, and when they were all rammed in place, the gravel was swept from the interstices between the stones, to the depth of one inch, and its place supplied with heated, clean sand, which was saturated as it was applied, with a hot mixture of coal-tar and coal-tar pitch, two parts of the former and one of the latter, filling the interstices level with the surface of the pavement, producing a smooth uniform surface. The first experiment was made about twelve years ago, and has proved a perfect success, the effect being to prevent the growth of all vegetation, while the surface being smooth prevents any clogging with leaves, dead wood, and the like. Another valuable result attained was that the pavement, being made water-proof, is hardly affected at all by frost, keeping its place much better than when the stones are set in gravel alone, in the ordinary manner. This concrete dressing is not adapted to use in gutters where vehicles are allowed to run over it, particularly in cold weather; but it is admirably adapted to use in side gutters for country roads, and is greatly superior to any other gutter for carriage roads and walks in private grounds. The cost is about two cents per superficial foot more than the ordinary stone-paved gutter.
COUNTRY ROAD ENGINEERING.
Road engineering as a profession has not been suficiently in demand in this country hitherto, to enlist the attention of those possessing experience, skill, and a thorough, scientific knowledge of the subject. The engineering of new roads and the alteration of old ones have generally been done by a land surveyor, or some student in railroad engineering, each deficient in a knowledge of the important work he attempts to execute; hence the defective character of most of these roads thoroughout the country. Not until the professional engineer shall receive greater encouragement to make common road engineering, in all its details, more a specialty, will it be more skillfully executed, and this encouragement will not be afforded until the masses are made more familiar with the importance of the subject.
There is one important principle in road engineering that should always control the grade of a road as far as practicable, and yet it is observed and acted upon only as the exception instead of the rule. It is that when a road is to connect two points, whether terminal or intermediate, and one is higher than the other, the inclination of the road should, if practicable, continually tend upward in one direction, and the reverse in the opposite. Instead of this we have examples all over the country where there is a descent, a fall in the grade, made up of a number of smaller or larger hills, from the low to the high point, that is really greater than the actual elevation of the high above the low point. A trifting divergence in the direction of the road, and frequently with
but a slight increase in its length, if any, will almost always remedy this great defect; so that a team, in traversing the road from the low to the high point, shall have but little, if anything, more than the real difference in the altitude of the two points to overcome. This error, if corrected in all existing cases in this country, would be of incalculable advantage to the community.
WIDTII BETWEEN FENCES.
It is important that the width of a road between fences should be ample to provide the material required in construction and repair, without endangering the fences by undermining the banks, and also to leave a grade that will be self-sustaining. Greater width is necessary in snowy districts than in those not subject to blockade from this cause. In the northern portions of this country there are districts where the cost of keeping roads open in winter exceeds that of repairs in summer. Increasing the width between the fences and keeping the gutters suitable for the use of sleighs have proved to be the most efiicient remedy. The width required by law varies in the different States from two to four rods. In the opinion of the writer the latter width is not too great to be economical for highways generally. Walls, close fences, or close belts of trees, on road inargins, are also objectionable, as they tend to blockade them with snow, and prevent the surface from drying.
SHADE FOR ROADS.
On all earth roads shade is objectionable in its effects on the surface, yet it is admissible to provide a good shade with deciduous trees on the summits, where the fullest benefit of the fanning breeze may be enjoyed, and shade will be least injurious. The effect of shade on stoned roads is less injurious than on those of earth. Abrupt banks or dense thickets on the south side of a road-bed, so high and near as to exclude the sun from it in winter, are very objectionable and dangerous, as such portions of the road are generally icy, when the remainder is free.
EXISTING ROAD LAWS.
There is a great similarity in the general road laws of the different States pertaining to the maintenance of county roads, the tax being generally a poll-tax on the male inhabitants between certain ages, though in some there is a trifling levy in money. The levy for the cost of new roads and bridges is usually in money, on all the taxable property in the rural districts. The system of labor-tax and of selecting road supervisors alternately throughout the districts, to direct the outlay of such tax, regardless of qualification or fitness for the work, notwithstanding it has so long and generally prevailed, is everywhere acknowl. edged to be very defective and unprofitable in its results.
All money required to construct and maintain the roads and bridges in each county should be raised by levying a tax in money. A compe. tent county road engineer should be permanently employed, who should have the entire direction of all construction and repairs of roads and bridges in his district, with the power to draw on the treasury for the necessary means to meet all reasonable requirements in defraying the
cost of the work to le esecuted. He should be authorized to purchase all teams, vehicles and implements required, the same to be the property of the county, and to employ as many competent foremen as required for his district. They should have charge of these teams, &c., and have power to employ, control and discharge the number of laborers directed to be employed by the engineer. The foremen should each have their respective districts allotted them to be kept in repair. The engineer and his foremen and the laborers employed should be required to devote their entire time to labor on the roads. The water bars, culverts, bridges, and gutters should be examined as often as once a week, and all loose stones, and other surface obstructions removed. Work for repair of surfaces should be constantly pursugil, and the principal amount of material required on the earth roads should be applied in the dry season. The winter should be devoted to quarrying stones for bridges, culverts, and macadamizing, and in raising and hauling gravel, and depositing it where it may be readily applied at the proper season. With such a force in charge of the roads the amount and quality of work executed would be more than double, and the actual tax required less than under the prevailing system.
COST OF ROADS AND EXPENSES OF REPAIRS. According to all the returns from different States, the average cost of construction of gravel roads is $2,241 per mile, and the average annual cost per mile for repairs is $103. It appears, from the reports, that only a very few of the roads are improved by a gravel bed, and neither the width of the beds so improved nor the quantity of material applied is given. We may reasonably infer, however, that neither is greater than is absolutely required, and yet we find the cost of construction per mile to range from $700 to $4,000, and to average $2,241. The annual outlay per mile varies from $4 to $200, the average being as above stated, $103.
By reference to the table showing the cost of repairs to common roads per mile throughout the country, we find it to vary from $1 to $59, and the general average is $18 11 per mile.
The returns show that the average cost of construction of macad. mized roads per mile is $3,290, and it varies in the different States from $500 to $6,336. The average annual cost per mile for repairs of macadamized roads, as reported, is $10, varying from $10 to $100 per mile.
The average cost of construction of plank roads per mile is reported to be $3,000, and the average annual cost of repairs per mile is $550.
The following, table, compiled from replies to circular issued by the Department, shows the average annual cost per mile of repairs of common roads in tlie respective States:
Xew Jersey.... Maseachusetts.. Rhodle Island.. Michigan...... Wisconsin.... Pennsylvania.. Maine......... Connecticut ... New Ilampshire Vermont........ Maryland..... Llavere ....
821 82 Virginia.... ......
$600 Missouri ..
70 Alabama..... 18 29" Mississippi. 40 00 Louisiana..
9 CO Texas....... 10 00 Arkansas..... 2300 Tennessee.. 11 00 1# Virginia 143) kestacky...
* Iowa....... 800 'Kansas.... 900 Nebraska. 795, l'tah..... 643 ('olorado .. 17 00 (alifornia..
1) Nevada.... 13 37 Onesou.....
03 00 10 (0
The writer has observed in various parts of the country common errors in bridge construction, which he proposes to notice, with remediai suggestions. At the present comparative prices of wood, stone and iron in all districts, except perhaps on extensive prairies, where the former two are very scarce, wood and stone are considered so much cheaper than iron that they are generally used. Where good quarry stones and suitable sand and lime or cement are conveniently attainable, the span required not more than thirty feet, rock foundations for the abutments within reasonable depth, and the banks of a proper height, the stone arch with stone parapets is, perhaps, as economical a structure as can be adopted. Where greater spans are required, and the banks are low, stone abutments and well constructed frame covered bridges are preferable. Not a doubt exists of the economy of siding and roofing wooden bridges, and of extending both over the abutments, so as to effectually protect from rain the timbers and planking at these points, as they are known to decay first when not protected. There is a frame covered bridge in Harford County, Maryland, which was built more than fifty years since, and is still safe.
Among the errors in bridge construction, those most common are the injudicious distribution of material, particularly of timber; the contraction of the water way, so as to expose the superstructure to liability to be swept from the abutments; neglecting to bolt the superstructure to the abutments; laying the flooring with close joints, instead of with proper openings, to prevent water from standing on the floors; using perishable varieties of timber, and even allowing the sapwood to be used in part, by which all is reduced to its ephemeral character. No error is perhaps more common, and none results in so need. less and speedy destrnction of the longitudinal timbers of bridges, as the want of attention to keeping them dry, where they rest on the abutments, and especially at the ends where they support the earth-filling of the road-bed.
The durability of the timbers may be increased by introducing a light back sill and short light joist about two feet in length, with a piank on edge resting against them, to support the filling independent of the main, horizontal timbers, that air may circulate around the ends; and by covering the ends of all timbers resting on abutments and piers with several thickness of tarred paper, these being the points where decay often destroys when the other parts are unaffected.