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vertical axes. A swing-bridge carries a road across the head of the lock. The lock-gates, sluices, swing-bridge, and four capstans on the lock-heads, are worked by hydraulic power under a pressure of 711 lbs. per square inch. The ship-canal connecting the lock with the Dantzig Vistula is about 1,300 feet long.
Parallel to the ship-canal, and about 330 feet higher up, is a canal constructed for the passage of floating timber, which, with an important timber trade, was necessary to avoid congesting the main canal at certain times of the year. The timber canal is about 3,280 feet long, 36 feet wide at the bottom, and has 1 to 1 slopes. The bottom is paved with granite, 1 foot thick, laid on concrete between longitudinal and transverse sheet-piling. The slopes are protected with brickwork on a concrete bed. The canal is protected from the entry of ice and flood-water from the cut, by a pair of lock-gates and a weir. The weir consists of two gates, swinging on vertical axes near the centre, Fig. 26, Plate 6, and it is placed close behind a pair of lock-gates, to equalise the water-level, so that these gates may be opened. The weir was made to turn on a vertical axis, instead of horizontally, because it was feared that, owing to the long time it would have to remain open, its chamber would otherwise become choked by the sand and mud with which the waters of the Vistula are laden. The difference of water-level, during the season for the passage of timber between the cut and the Dantzig Vistula, is never sufficient to cause too great a velocity in the canal, so that during this period the gates and weir stand open. To enable the timber canal to be used, in case of need, for the passage of vessels, and for a tug and train of barges, a second pair of iron gates was provided, 984 feet below the first pair. Sluices have been constructed through the side walls of the gates, to allow the lock-chamber, 984 feet long, to be emptied as quickly as possible. The cost of these additions, for the navigation, was £80,000.
On the left bank of the Vistula, it was necessary to set back the embankment for 6% miles above the cut, as the narrowing of the river at this part was dangerous in two ways. During floods, ice was driven against the embankment and threatened to destroy it; and the decreased width pent up the water, and hindered the discharge of the ice. The cost of this work was £180,000, half of which was for land. The total cost of the works described above amounted to about £1,000,000.
The Paper is accompanied by drawings, from which Plates 5 and 6 have been prepared. [THE INST. C.E. v.C.L. cxxxv.] S
(Paper No. 3097.)
“The Management, Maintenance and Cost of Public
THE management, maintenance, and cost of public roads are matters which very materially affect the economy, convenience, and comfort of the inhabitants, and are of great importance to trade, in any locality. This is especially the case in countries which, like Ireland, are deficient in railway accommodation.
The original Act which consolidated and established the present grand jury system came into force in the year 1836. Under that and subsequent Acts all public county roads, county piers and harbours, bridges, and county buildings, baronial light railways and tramways, constructed with county guarantees, were placed under the supervision or control of grand juries. The existing system, therefore, had barely completed its diamond jubilee, when its death-knell was sounded by the announcement of the proposed substitution of elected county councils for the present grand Juries.
In their original composition, though they included the principal landowners and others having the largest vested interests in the country, these juries were not constituted on a basis of popular election. They, however, included a legally qualified representative for each district (barony). Since the year 1836, these bodies have been deprived of almost all powers of taxation, such powers being now delegated to the district boards called the Baronial Presentment Sessions, representing the baronies into which each county is divided; but the number or extent of the baronies are not of any fixed ratio or proportion; they vary largely, ranging in areas between 8,000 acres and 310,000 acres. These boards are composed of the magistrates of the district, together with a statutable number of the largest ratepayers of each district, whose names are drawn by ballot out of a selection of twice the statutable number placed on lists made out at each previous assizes by the grand jury.
At the Courts of Presentment Sessions (or Baronial District Boards) all applications for works and expenditure must be made. The County Surveyor examines into all the proposed works, estimates their cost, and attends the Baronial Sessions as professional adviser, stating also the nature, necessity or utility of such works, and the sums which it would be proper to grant. The Baronial Sessions then decide by a majority of votes, first, either to approve or reject, and then, if the works are approved of, the sums which they will grant. It is usual for the Boards to be guided in these matters by the advice of the County Surveyor, but sometimes other influences are at work and professional advice is disregarded. Such works as are sanctioned are then advertised for tenders and subsequently sent up to the grand jury for approval.
The supervision and control of all public roads which are under presentment for maintenance and repair are vested in the County Surveyor, and form a very important part of the duties attaching to that office. From the nature of their appointment, which is by open competition, conducted by the civil service commissioners for each vacancy, County Surveyors must not only be highly qualified engineers, but they are also free from any party influence. The regulations relating to County Surveyors' examinations are given in Appendix I. As government officials they have an important and responsible position, though they are at times liable to serve as buffers between the ratepayers and interested or unprincipled parties, who have considerable power over them, and with whom they may not infrequently come into collision. The Assistant Surveyors are appointed by the County Surveyors, so many as the grand jury may consider necessary, but before an assistant can be appointed he must have a certificate of qualification from the Board of Public Works in Ireland. In order to obtain this certificate a nomination from a County Surveyor is necessary, recommending the candidate as a fit and suitable person for the appointment, and requesting the Board to admit him for examination, and, if the result is satisfactory, a certificate of qualification is sent to the County Surveyor, who, if he does not appoint the candidate, is requested to return the certificate to the Board of Works. These examinations are chiefly in arithmetic, mensuration, calculation of quantities, chain surveying, levelling, brickwork and masonry.
Under the grand jury system all public works must be submitted for contract, and the lowest tender must be accepted, if such tender is considered bond fide, and if the sureties are sufficient. In cases where a work is not tendered for, the grand jury are, however, empowered to entrust the same to the County Surveyor and to direct him to execute it at a cost not exceeding the amount agreed upon by the Baronial Presentment Court. Under the original Act of 1836, this latter power did not exist, and consequently, in the absence of tenders, no work could be carried out under grand juries, a fact which was the cause of great inconvenience. Thus, in King's County more than 400 miles of important roads were at one time almost impassable, as no contractors could be induced to tender for their repair and maintenance, except at fabulous prices, settled by themselves. In order to remedy this state of things, a former County Surveyor, the late Mr. John Hill, M. Inst. C.E., with the aid of the county members and others, was instrumental in obtaining the Act, 20 & 21 Vic. c. 15; under which Act grand juries were empowered, in the absence, after due advertisement, of suitable public tenders, to cause the works to be executed by the County Surveyor, the cost being, however, limited, as above mentioned, to the amount originally fixed by the Baronial Presentment Sessions. The working of this Act has been of considerable public advantage, and has resulted in great economy, though it has entailed in many cases a vast amount of extra labour upon the County Surveyors, without additional remuneration. In cases of sudden damage to roads, bridges, &c., by floods, landslips, or otherwise, the magistrates at petty sessions in the districts affected have special power to provide sums up to £50 for repairs; and in cases where larger sums are required, the lordlieutenant can order Special Baronial Presentment Sessions to be held for the purpose. Provision is also made for repairs in cases of emergency, where the delay of waiting for Baronial Sessions would cause great public inconvenience. The question of the amount of money to be expended on the repairs and maintenance of any road is settled by a majority of votes at the Baronial Presentment Sessions, and the County Surveyor furnishes estimates of expense and all necessary particulars as the professional adviser. At a subsequent sessions, which must take place after the lapse of a period not exceeding 30 days, tenders are received, contracts are drawn up, with complete bonds and sureties, and these documents must then be sent up to the grand jury, who can either adopt or reject them, as they may think fit. They have no power to alter them. All contracts are made with the Crown, and are free from stamp duty. The contracts for repair and maintenance of roads may be entered into for periods of 7 years, but the average periods are between 3 years and 5 years. Payments on such contracts are made twice in each year, directly after the spring and summer assizes. These contracts are generally let to local farmers, or to persons engaged in business in the district. The roads are divided for contract purposes into lengths, which vary between + mile and 5 or 6 miles, according to class and local circumstances, but the methods in different counties in this respect may vary. The materials required for the repair and maintenance of the public roads are procured under the special provisions of the Act, which gives large powers to enter upon (with certain exceptions) private property for this purpose, if it is proved to the satisfaction of the magistrates that suitable materials cannot conveniently be obtained elsewhere. The majority of the public roads in Ireland have originally been badly constructed, and this is especially the case with those roads, hill-cuttings, retaining-walls, &c., carried out by the government as relief works during the famine years 1846–8. The works of a similar kind carried out under the supervision of the County Surveyors under the Relief of Distress Act, 1880, are in striking contrast to the earlier undertakings, and the expenditure in proportion to the amount of work done was very much less. An outline of the method of road construction adopted by the Author may be given. For a main road, running through sound upland districts, as soon as the work of making the open side drains, cuttings, embankments, bridges, culverts, fences, &c., and the formation level is well consolidated, it is thoroughly drained by mitre and covered longitudinal side drains, made with stones, and discharging by small cross drains or pipes under the sides, footpaths, and fences, into the open back drains. Stone pitching, of size and depth calculated according to the traffic the road is intended to carry, is laid carefully on the formation level, closely packed, levelled, and formed to a convex cross section, and joined into the tops of the longitudinal (covered) side drains. For roads carrying very heavy traffic, and town streets, the pitching generally consists of stones about 9 inches in depth, well rammed. In country districts, the pitching consists of one or two layers of 6-inch to 4-inch and 3-inch to 24-inch stones. When the pitching or foundation has been well rammed and levelled, the “macadam” metal, broken to 2-inch gauge, is spread in layers not more than 3 inches deep at a time, and blinded over with fine screening, gravel, or other suitable materials, and the road is opened for light traffic; the succeeding layers of metal are applied