3. A beam of length l is loaded with a weight of w per unit length. Compute maximum bending moment and shearing force, and draw carefully to scale diagrams of bending moment and shearing force in each of the subjoined cases :— (a) Supported at each end. (b) Supported at the centre. (c) Supported at two points distant from the ends. 4. A beam of cast iron 1 inch square and 3 feet span broke with a central load of 800 lbs. Compute the strength of a beam of the same iron of circular section 3 inches diameter and 4 feet span under a uniformly distributed load. 5. Determine the modulus of section of a rolled girder of the following dimensions: 6. A tension bar in a bridge is 5 inches wide and inch thick. Make a full size drawing of a rivetted joint for this bar, and supply all necessary computations of strength and efficiency. 7. The piston rod of a steam engine is fixed to the crosshead by a cotter, the dimensions being as below:: Diameter of rod, 1 inches. Discuss the strength and factor of safety against all possible modes of fracture of this rod and cotter, the piston being 12 inches diameter and the pressure of steam 80 lbs. APPLIED MECHANICS. SECOND PAPER. The Board of Examiners. Only FIVE questions to be attempted. 1. A lattice girder consists of 10 panels, and has a double triangulation at 45°. Compute stresses under loads of 10 on each upper, and 5 on each lower intersection, and check your results by graphic statics. 2. Compute and also determine graphically the stresses on the above girder, with loads of 10 on the upper intersections for one-half the span, and 5 for the other half span. 3. What is the average statical tensile breaking stress per square inch of wrought iron and mild steel, and what should you consider the maximum permissible working stress in each of the following cases : (a) Steady load. (b) Load varying from 1 to 3. (c) Load varying from zero to a maximum. (d) Load varying from a given tension to an equal compression. Give reasons for your answers. 4. What are the general principles by which you would be guided in determining the form of an arch under any given distribution of load? Give sketches and brief descriptions of arches to carry the following loads: (a) Uniformly distributed along arch. (d) Small load distributed uniformly along arch itself, and a large concentrated load at quarter span. (e) Liquid load bounded by horizontal upper sur face. 5. What is meant by the funicular polygon? Show how it is drawn. 6. A beam 9 inches wide and 3 inches deep, deflects 1 inch under a given load. How much will a beam 3 inches wide and 9 inches deep deflect under the same load? Suppose the two beams so connected as to be constrained to deflect equally, what proportion of the total load will each bear? 7. Describe the process of testing a specimen of mild steel in the testing machine, and draw the stressstrain diagram, marking on it the yield point, extension, and breaking load. CIVIL ENGINEERING.-PART I. FIRST PAPER. The Board of Examiners. 1. Make a series of detailed sketches of a hydraulic dredging machine. Give the name and use of each part of the mechanism, and state under what circumstances such a machine can be profitably employed. 2. Write a brief essay upon modern explosives, and their use for rock excavation. 3. Make detailed drawings of one span of the ordinary type of small railway bridge used in Victoria, and point out what special precautions you would take to secure good material and workmanship. 4. Describe fully the process of making a steel girder for a bridge, and supply sketches of the various tools and machines used. What tests would you apply to the material and workmanship? 5. Describe fully the process of building a brick arched bridge of about 40 feet span, and supply a detailed dimensioned sketch and description of the centering required. 6. Write an essay on the manufacture, use and mode of testing Portland cement for engineering works. CIVIL ENGINEERING.-PART I. SECOND PAPER. The Board of Examiners. Supply working drawings and specification of material and workmanship of any two of the following (a) A picket fence and small gate for foot passengers suitable for a public park. Gate must admit perambulators but exclude cattle. (b) (c) A foot-bridge having iron girders and timber deck of the following dimensions Clear span 25 feet. Width 6 feet. The abutments are of brick and need not be shown in detail. A brick barrel culvert, 3 feet internal diameter, under a railway embankment, 20 feet high and 18 feet wide at formation level. CIVIL ENGINEERING.-PART II. FIRST PAPER. The Board of Examiners. 1. Give all the information you can as to the various kinds of stone used for road making, including the method of breaking, testing for gauge, and spreading. |