Imágenes de páginas

Report on the Examination in Building

Construction and Drawing.


Results : 1st Class, 918 ; 2nd Class, 1,282 ; Failed, 1,208 ; Total, 3,408.

Speaking generally, the improvement in drawing is undoubted, many of the sketches being excellent and far better than the tracing. The knowledge of elementary construction is very fair, but there is a general lack of practical knowledge of materials, and this could be obviated in the way that has been suggested in the remarks on Questions 3 and 10. The powers of description are bad, and great carelessness is shown in not following the instructions, in misreading the questions, and in selecting the questions to be answered. It is probable that far better results in these examinations would be obtained if, towards the close of the course, teachers were to give an hour's written examination to the whole class as á test. It is clear that in many cases the candidates have no idea of what a written examination is, and consequently waste valuable time at the beginning and are much hurried during the last half-hour. Q. *1. Make a neat tracing in ink of the drawing given, with the

writing : the lines should be firm and solid and should finish

accurately at the proper points. The general average of the tracing has certainly improved since attention was drawn to it two years ago, but many of the tracings are still very bad, some of the worst being done by candidates whose pencil sketches are very fair indeed. This would indicate that more attention should be given to tracing in the Schools. Many marks were lost through candidates' carelessly omitting to trace the printing and writing as well as the drawing. Full marks were gained by 176 students, while 127 were so bad that no marks could be given. Q. 2. Describe fully what you know of blue lias lime, its origin, manu

facture, preparation and the precautions to be taken in its use. This question was attempted by only 365 candidates, and was badly answered on the whole. Very few of those who tried the question seemed to be aware of the difference between blue lias and common lime. Only two candidates obtained full marks, 55 got none.

[ocr errors]

Q. 3. What are the essential properties of a good brick? Distinguish

between the following bricks, and state for what purpose they are chiefly used : Fletton, gault, red rubber, blue Stafford

shire. This was attempted by 1,066 candidates; the first part of the question as to the properties of a good brick was fairly well answered, but the latter part badly. Fletton bricks, though so largely used now, seemed to be unknown to all but a few, and the vaguest notions prevailed as to gaults. This shows the want of practical teaching. It should surely be possible to have in all schools specimens of the various kinds of brick's in ordinary use, so that the students might see and handle them for themselves. Full marks were awarded to 10 candidates, 40 obtained no marks. Q. 4. Show by a sketch on your squared paper how a pole should be

slung by a rope for lifting vertically. This eminently practical question, although attempted by 1,216

candidates, was answered very indifferently. Many quite misunderstood the question and sketched elaborate pictures of posts with guy ropes, or rough Derrick arrangements, and a very slight amount of consideration should have shown a number of the candidates that by no possibility could a pole



be lifted vertically by the methods indicated in their sketches. 117 answers were awarded full ‘marks, while the fact that of those attempting the question, 680, or 56 per cent., obtained no marks speaks for itself. Q. 5. What is the size of a countess slate ? Describe clearly and fully

what is meant by “lap," and “gauge” in a slated roof, and

illustrate your answer by sketches. This was attempted by 3,004 candidates, or 90 per cent. of the whole number, and 205 obtained full marks. Attention was called last year to the total ignorance displayed by many candidates as to what “lap” in a tiled or slated roof means, and the same lack of knowledge was very apparent this year. It is extraordinary how many candidates showed both by their descriptions and their sketches that they were under the impression that “ lap" is the amount which the tail of one slate projects beyond the head of the course immediately below it, so that over a large portion of a roof there would be only one thickness of slates and never more than two. This ignorance on such a simple practical matter is not creditable to the teachers. As there were three parts to this question, most of the candidates obtained some marks, but 225 failed altogether to get any. Q. 6. Draw to a scale of 1(1” to a foot) the plans of two consecutive

courses of a square three-and-a-half-brick pier in Flemish bond :

the joints may be shown by single lines. This was the most difficult question in the whole paper, and though it was attempted by 1,905. candidates, the results were very poor, Marks were given for any intelligent attempt to keep a face of Flemish bond and to minimize the number of straight joints. But in a large number of cases no bond whatever was shown in the thickness of the pier and no attempt made to break the vertical joints. Only 77 obtained full marks, and 547 failed to get a mark. Q. 7. You have the choice of the following stones in building a mansion

with stables attached : state in what parts you would use them, giving your reasons : Granite, Whinstone, Hard York, Craig. leith, Portland whitbed, Box ground Hopton Wood, Derbyshire

marble. Very little attention seems to be given to the nature and characteristics of building stones, although the subject is distinctly mentioned in the Syllabus. The question was attempted by only 304 candidates, or less than one per cent., and nearly all the answers were poor ; five candidates got full marks, 24 none.

Q. 8. Sketch full size on your squared paper a vertical section through

the junction of two 3-inch round cast iron rain-water pipes, and

describe the method of jointing. This was attempted by 2,241 candidates of whom only 35 obtained full marks. The descriptions were generally very meagre and the sketches poor; also carelessness in reading the question led several candidates to draw the junction between two lead pipes. It is curious that in many cases the pipes were shown with their ends simply butted together and secured by an iron collar. 412 candidates failed to get any marks, Q. 4. A York stone sill is described as "7" x 4.5" rubbed, weathered,

and throated.” Draw to ą scale of } (1?" to a foot) a cross section of this sill, and describe in their proper order the

operations of the mason in preparing it. 2,064 candidatos attempted this question, and tho drawing of the stone Bill was generally good, but the desoription of the proper order of the mason's operations in preparing it were generally poor and showed a lack of practical knowledge, 33 obtained ful! marks, 41 none

Q. 10. If lead weighs 710 lbs. per cubic foot what is the thickness of 6 lb.

sheet lead? What weight lead should be used for flats, dormer cheeks, flashings, hips and valleys, soil pipes ?

1,003 candidates tried this question, and a considerable number worked out the thickness correctly, but the second part of the question was badly answered, many having no idea of the weight of sheet lead for practical purposes. 24 Ib. and 30 lb. lead for flats, and 10 lb. for flashings, being instances of what must simply have been wild guessing. If the schools were only provided with a few specimens of 5lb., 6lb. and 7 lb. lead for the students to see and handle such ignorance as is displayed in the answers to this question would be impossible. 112 got full marks, 82 failed to get any. Q. 11. A window opening 3 feet wide is spanned by a wooden lintel

4" deep with 6" bearing at each end. Draw to a scale of it (1" to a foot) an elevation of the opening and the lintel with a

segmental discharging arch over it in two half-brick rings. This was the favourite question, and was attempted by 3,054 candidates, and on the whole was well answered, though the mistake was too frequently made of letting the arch spring from the lintel, instead of forming a proper skewback quite clear of the end of the lintel. This mistake, which is very common in inferior work, ought to have been avoided. 846 answers were given full marks ; 286 failed to gain any marks. Q. 12. A compound girder is composed of a 12" x 5" rolled steel joist with

a 9" x 1" steel plate top and bottom. Sketch on your squared paper one quarter full size (3” to a foot) a section through this

girder : the rivets need not be shown. This question, which was intended to test the knowledge of the students as to what a rolled steel joist is, was attempted by 2169 candidates Although some of the sketches were excellent, 100 obtaining full marks, many candidates had no idea of the shape of a R.S.J., and sketched the most preposterous forms. It would have been thought that no ambiguity could possibly exist in this question as to what was required, and yet in a large number of cases two joists were combined either alongside or on top of each other. 513 obtained no marks.


Results : 1st Class, 605 ; 2nd Class, 1,437 ; Failed, 655; Total, 2,697.

The work, as a whole, in this stage was a decided improvement upon that of last year, but many of the attempts were so bad that the candidates would have failed to pass even in the previous stage. It cannot be too often repeated that a candidate for any of the higher stages should have previously passed first class in the one below. It would also be a great advantage to students if in the course of their instruction they had occasional short test examinations for practice in drawing up intelligible descriptions and preparing drawings to given conditions. Q*21, Make a neat tracing in ink of the drawing, Figure 21, with the

writing and figures, The lines should be firm and solid and

should finish accurately at the proper points, About threo per cont, obtained no marks, and only 11 per cent, full marks, It was on the whole fairly well done, but the printing and dimensions were, as is usually the case, very weak. This may have arisen in somo instances from the position of the candidate with regard to the light in the examination room, but it was probably more often due to want of practice

Q. 22. Describe fully the preparation of the trench, the mixing and laying

of the concrete, and the laying and jointing of the pipes in a straight run of 4-inch glazed stoneware house drain laid at an average depth of 3 feet. Draw, half-full size, a longitudinal

section through one of the joints. Attempted by 1,986, of whom 25 failed to obtain any marks and 4 obtained full marks. Such parts of the question as were covered by textbook knowledge were well answered, but the practical parts, such as boning the trench to a regular fall, driving pegs for the level of the concrete, and leaving a hand-hole under the sockets, were very weak. The drawing of a finished joint in section was disgraceful, not more than half a dozen out of many hundreds being even approximately correct. The majority rounded over the bottom of the socket into the bore of the pipe and showed the socket about four times too deep. Some specified that the joints were to be made with concrete, but nearly all gave neat cement instead of adding a small portion of sand, up to, say, j, as a provision against expansion. Many assumed 4" as the outside diameter of the pipe. Q. 23. Draw to a scale of 11 (1" to a foot) the elevation of 4 feet run of

a half-brick honey-combed sleeper wall 8 courses high including footing, and the ends of 4 joists suitable for a span of 6 feet; also draw a cross section of it showing the sleeper and joist. Show the joints of the brickwork and state under what circum

stances a damp proof course would be required. Attempted by 1,298, of whom 33 failed to obtain any marks and 15 obtained full marks. This was, on the whole, fairly answered but many omitted the wall plate and carried the openings into the top course, giving no stability. The joists proposed for the span of 6 feet varied from 3" x 11" to 9" x 3" the proper size being about 5" x 2".

Q. 24. Sketch on your squared paper a hand mortising machine for

working timber, and describe how it is used. Attempted by 676, of whom 18 had no marks and 24 full marks. This question was remarkably well answered ; the sketches were in general not only in fair proportion but showed very clearly the construction and manipulation. The information had evidently been derived at first hand, Q. *25. The diagram, Fig. 25, shows a three-light opening in a ground

floor room : the centre is to have a pair of French casements opening inwards and the side lights double hung sashes. Draw to a scale of (1" to a foot) a plan through the central and one side opening showing frames, casements, &c., and a vertical section to the same scale through the bottom rail of the French

casement. Attempted by 1,122, of whom 85 got no marks and only 3 obtained full marks. Although attempted by a large number there were very few good answers. The majority were unable to draw a passable section of the bottom rail and sill of the casement, and many designed it in such a way that the door would neither open or shut, nor keep the rain out. The left hand leaf of the casement was in many cases made to open first. Q. 26. Explain fully what is meant by the terms "render, float and set"

on brickwork. Describe the composition of the stuff used for

each operation and the mode of executing it. Attempted by 1,440, of whom 44 did not obtain any marks and 13 were awarded full marks. Fairly well answered but in many cases too briefly. An excess of sand for the lime to carry was frequently given. Portland cement was frequently specified instead of lime, whereas if cement had been intended the question would necessarily have said so. Q. 27. A cistern is required to hold 1,000 gallons; what should be its

length, breadth and height, and of what material should it be constructed if used for storing drinking water? What would be the weight of the water in the cistern when full ?


Attempted by 742 ; 47 had no marks and 16 full marks. Some of the answers to this questions were ludicrous, outrageous sizes being given. Very few allowed for a margin above the surface of the water for overflow, etc. No consensus of opinion existed as to the material of the tank; nearly every material was specified in turn. Q. *28. The diagram shows a block of stone being lifted by a sling chain

and dogs'; with a pull of 5 cwt. in the crane chain show graphically what the stress will be in each part of the sling chain surrounding

the letter A, assuming free play at the eye of the dogs. Attempted by 723 ; 112 had no marks and 22 full marks. This was a very elementary example but only a few candidates gave complete answers. They were nearly all wrong with the stress in the horizontal part of the chain which they worked without due regard to the result in passing through the dog. Very few realised that the stress in the horizontal part of the sling equalled that in the other parts. Practically no candidate appeared to have been taught that "lines drawn parallel to the forces acting at the angles of a frame in equilibrium form a closed polygon," and its corollary that " lines drawn from the angles of this polygon parallel to the sides of the frame must meet in a point and determine the magnitude of the stresses in the sides of the frame." Q. 29. An internal brick wall 12 ft. long has to be removed and replaced

by a fir beam which has to carry a distributed load of 4 tons. Calculate the scantling of the beam. If the same load, instead of being distributed, were concentrated at a point 4 ft. from one end, would you consider the beam strong enough? Give your

reasons fully. Attempted by 412 ; 65 had no marks, 17 full marks. There was, as last year, a general failure to comprehend the principles of the strength of beams. Some most elaborate answers ended with impossible results. Wrong formulie were frequently used, and fect and inches, tons and cwts. hopelessly mixed. Teachers should explain the general principle by leverage moments and not rely upon formulæ which are as likely as not to be wrongly applied. Q. 30. Draw to a scale of } (1}" to a foot) a section through two consecutive

spandril steps with moulded nosings of a hanging stone staircase

and describe clearly how such a staircase is constructed. Attempted by 1,154, of whom 37 failed to obtain any marks and 7 had full marks. This question was well answered by several candidates who knew the practical difficulties of fixing such steps and how they were overcome. Those who relied upon book knowledge indicated it very plainly and failed to give a reasonable description of the fixing, while in very many cases their section of the steps was absurd. Q. *31. The diagram is an outline plan of a first-floor room which is to

have a single-joisted floor : state the number, lengths and scantlings of the timbers which you would require for the plates

and joists--including trimmers--for this floor. Attempted by 1,973 candidates of whom 73 got no marks and 14 full marks. The same want of knowledge in determining the sizes of joists was shown as in last year's papers. The simple practical rule of take

" half the span in feet, add two and this gives depth in inches, one-third of depth gives thickness” would in many cases have made the difference between success and failure if it had been applied. Scantlings of different depths were often given. Q. 32. Explain clearly the various ways in which the water seal of traps

of sinks and w.c.'s is lowered and rendered ineffective, and state what precautions you would take to prevent this; illustrate your

answer by sketches. Attempted by 820, of whom 76 had no marks and 4 full marks. Sketches were not so frequently made use of as they might have been, and, owing to their absence, the descriptions were often not very clear. The


« AnteriorContinuar »