Page:The Building News and Engineering Journal, Volume 22, 1872.djvu/375

 MAY 3° 1872. THE BUILDING NEWS. 353 The quantity that can be removed, when the ground is clay, marl, gravel, or similar earth, is about seven cubic yards per man per day, counted all round—in sand rather more, and in shale rather less. In rock powder takes the place of picks, and the quantity ceases to be reckoned at per yard per man per day. It may here be said that in schedules of prices t> be attached to tenders, the kinds of earth above-named, together with others of like kind, are sometimes all included under the general head of ‘‘ common earth,” as dis- tinguished from ‘ rock,” the tender being made out at one price for an assumed total quantity of common earth in a cutting, and at another price for the assumed quantity of rock which may have to be removed; extra quantities of either being added to or de- ducted from the contract sum accordingly as the actual quantity of each may be proved in the execution of the work. Engineers, how- ever, do not always give a contractor this safe basis to make his tender upon, but throw upon him the responsibility of com- pleting the work, however much the relative quantities of the two kinds may differ from those assumed at first, and the consequence is that the company—which means ulti- mately the public—have to pay for the con- tractor’s risk, for when but little information is given to him of the actual character of the work he is asked to undertake, and he is obliged to rely for his safety on his own judg- ment alone, or even in any great measure, he is sure to try to ensure himself against loss by adding something to his tender for possi- ble contingencies ; or, rather, since it is but mere prudence to add something for con- tingencies under the most favourable cir- cumstances, he adds an undue amount to cover the greater risks which he ought never to be called upon to undertake. Granting that the engineer himself cannot know abso- lutely the relative quantities of common earth and rock, yet he ought to know more of the ground by borings and trial-holes than an intending contractor can know, and ought to place the contractor in a safe position by pay- ing him for actual work done. But this, it may be said, would destroy the charm of the contract, and deprive contractors of the pleasure of adventure. Let it be so, in so far as speculating on the nature of the work to be done goes; there is always sufficient room for emulation in the manner of conducting the work, although its quality and quantity be known beforehand. But to return to the quantity of work capable of being done per man per day: although 7 yards is a fair average, the quantity is very much governed by the weather, not more than 5 cubic yards of the same kind of ground being removable in a hard frost or in wet weather, while on some days as much as 9 or 10 cubic yards per man per day may be done. Taking an average of 7 yards in ground that requires but little getting, and taking the average day’s pay at 3s., the cost is a trifle over 5d. per cubic yard, to which must be added the interest on the money expended in plant, its wear and tear, the maintenance of the road in repair, the cost of tipping, the cost of leading from cutting to embankment, and the superinten- dence of the whole. The interest on the money expended in plant, its wear and tear, and the repairs of the road, increase with the length of lead ; but, taking a lead of 1 mile, the various items which make up the total cost per cubie yard are about as follow, for average materials :— Getting and filling wo... 5d. Leading to tip 12 Eiipppin cie-s:-6-0. 3 Interest on plant and wear and tear (waggons 14d., rails 3d.) 2 Maintaining road .... eee Superintendence Cost per cubic yard ......... 10 To this may be added any profit that may be | desired, the legitimate profit per cubic yard being less for large than for small total quantities. Tn estimating the time required in which to perform a given quantity of earthwork no more than 240 working days in the year can be relied upon in England, the number of working days per month varying from 14 in winter to 24 in summer, and the number of working hours per day from 7 in winter to 10 in summer, when the work is to be performed by one set of men, but when time is of such im- portance that two sets of men, or shifts, are employed, the working hours per day may be extended to 18 in May, 20 in June, 20 in July, and 18 in August. The scale stands thus :— January... 7 working hours per day. February Gi a March =... 9 33 TAP snes 14 a IVISLV eee: 18 +5 June ...... 20 oA Oily messes. 20 a August ... 18 3 September 12 1) October... 10 9 November 8 5 December 7 ” 150 There being onan average 20 working days per month, the total number of working hours per annum is thus found to be 3,000 under the most favourable circumstances, but when only 10 hours a day are worked through the summer, the number of working hours per annum is not more than 2,200. SECTION The gullet is not cut quite down to the formation level of the cutting, 2ft. or 3ft. in depth being left in the bottom, which is taken out after the bulk of the earth has been removed, and is worth 2d. per cubic yard more than the bulk. The full waggons are let down the inclines either by locking the wheels—“ spragging ” them with a piece of wood something like an Indian club, the “‘spragger” jumping up behind and returning with the empty waggons—or by brakes. ‘The former is the more effectual way when a trust- worthy man is employed, although somewhat dangerous to himself. Brakes are liable to get out of order by being strained in the rough usage they are necessarily subject to, and when that occurs and_ sufficient hold upon the wheels is not had, the men, horses, and waggons at the bottom of the incline are very liable to acci- dents. Fig. 7 represents the plan of a cutting being excavated by means of a gullet and in- clines, and Fig. 8 a vertical section of the same. ‘The arrows indicate the places from which the bottom set of waggons is filled, the foremost from the face and sides, and the middle and hinder ones with barrows from the higher lifts. ‘The waggons on the second lift are filled in a similar manner. When a vertical face has been formed, earth is most economically got by ‘ falling” several yards at once—first, by holing the bottom, leaving legs to support the face until it is ready to be ‘falled,” and then driving stakes along the top at the distance of a yard or two back from the face, the legs haying been first removed ; but from carelessness of their lives and limbs nayvies often subject themselves to accidents by carrying on the two operations of removing the legs and driving the stakes at the same time. The earth is often thus sufficiently broken up to be filled into waggons or barrows with shovels without further use of the pick. Shovels for this kind of work are round nosed, or rather pointed. They are of three sizes, No. 3 being 114in. broad and 13in. long, No. 4 12in. broad and 13}in. long, and No. 5 124in. broad and 14in. long. When bought in quantities No, 3’s are worth 27s. per dozen, No. 4’s 28s., and No. 5’s 30s. per dozen. These are hammered and ridged. ‘Those made in a different manner, called planished, are about 2s. less per dozen. For taking off the top soil, a spade is the best tool. For digging clay, a long narrow hollow tool is best, mea- suring about 7}in. wide at the bottom, and 63in. at the top, the length being 12}in. They are worth about 26s. per dozen. Picks are made of a good quality of iron, and are pointed with steel. It is necessary that the quality of the iron should be good, in order that the eye may not split in heavy work, but no wrought iron is hard enough to stand against the wear caused by the severe friction of the earth every time the point is forcibly driven into it. A good weight of pick for general use is 8lb. or 8Hb., but large picks are 10]b. weight. Shorter and lighter picks are used for driving headings, of about 6lb. weight. Picks are worth about 32s. per cwt., on an average of sizes, when bought in large numbers. ———__>—_—_ THE COST OF PUBLIC BUILDINGS. pete KS and mortar always make a heavy item in the Civil Service Estimates, and this year will be no exception from the general rule. The vote proposed for the new Courts of Justice will comprise £4,000 to complete the £954,000 for pur- chase of the site, and a vote of a second sum of £30,000 towards the £750,000 for the erection of the building. There is to be a further vote of £100,000 towards the estimate of £285,186 for new offices in Downing-street for the Home and Colonial Departments, &c., on which above £100,000 has been already expended. The vote for Burlington House is to be £47,000, leaving less than £7,000 to be hereafter voted to make up the estimated £178,000. The vote proposed for the enlargement of the Na- tional Gallery is £50,000, leaving only £33,000 more to come in order to make up the original esti- mate of £92,975. The vote for new buildings at South Kensington is £29,674, completing the £195,000, the original estimate. A vote of £40,000 will be proposed for the erection of a Natural His- tory Museum; the estimate is £350,000, and only about £6,000 has yet been expended. The Post Office requires a vote of £119,700 for new works and alterations—£59,500 completing the estimated £150,000 for the new offices in S. Martin’s-le-Grand ; £8,000 for a tunnel between the old and the new offices; £26,000 for the new Post Office (and the site) at Birmingham, £15,000 Neweastle-upon-Tyne, £6,000 Aberdeen, £5,000 Colchester, and smaller sums for other new post offices, some serving also for the Inland Revenue Department. There is a vote of £9,938 for new or enlarged County Court Houses at Halifax, Barnsley, Peterborough, Grayes- end, and other places. ‘The vote for the construc- tion of harbours of refuge is £35,130, and includes £4,000 for Dover, leaving little of the estimated £725,000 to follow; and £23,185 for Holyhead, nearly completing the estimated £1,545,000. The vote for public buildings in Scotland includes £20,000 for Glasgow University buildings, leaving only £20,000 to be hereafter voted to complete the esti- mate of £120,000; and £11,200 for the Industrial Museum at Edinburgh, in addition to £20,000 al- ready expended of the estimated £53,336 for the work. Ireland is to have £45,032 for new works and alterations at Coastguard stations, schools, post offices, &c. Abroad we find £25,000 required for the restoration of the Embassy building at Con- stantinople, £34,000 for Consular buildings in China and Japan, and £12,000 for a new Mission House at Teheran. Altogether, we are not bad customers of the builders. —__>—__—_. The Town Council of Weymouth have adoptea Sir John Coode’s plans for the drainage of Wey- mouth, instructing the town clerk to apply to the Local Government Board for authority to borrow £25,000 on mortgage of the general district rates. he plans have been forwarded to the Local Govern- ment Board for approval. The work, if carried out, will, it is said, put the town in a thoroughly sanitary condition.