The Largest Masonry Dam in the World.

The Largest Masonry Dam in the World.

What is said to be the largest masonry dam in the world is situated about sixty-five miles north of Bombay, India, to impound water in the Tansa valley for the purpose of giving Bombay a new water supply. It is a little over two miles long, 180 feet high and about 100 feet thick at its greatest depth, with a top width of 15 1/2 feet. The bottom of the inside base is slightly battered for a short distance, the balance being perpendicular. The bottom of the outside base has a straight slope, above which it is curved, with a radius of 160 feet. The waste weir is three feet below the top of the dam and about 1600 feet long. The entire foundation of this dam is solid rock throughout, and in some cases has been carried forty-five feet below the original ground level. The whole of the masonry consists of uncoursed rubble, anything approaching horizontal joints being carefully avoided. Every stone was carefully laid in mortar and driven home with a light mallet. The top course of the dam was by the use of carefully selected flat top stones brought up to a uniform level, having the appearance of rubble paving. The quantity of loose rubble stone used amounted to 14.707.000 cubic feet. The mortar used in the masonry consisted of one port of kunkcr lime to one and one-half of washed sand, with the exception of the lower and thickest portion of the dam in the bed of the river, where a portion of Portland cement was added to the above. The total quantity of washed sand used in the works amounted to 3,000,309 cubic feet. The total quantity of lime used was 2,206,000 cubic feet. During the working season as many as from 700 to 900 cirts were employed in the conveyance of lime, sand, etc., to the work. Regularly during the process of the work portions of the mortar were sampled, by being made into four inch cubes and after drying for forty-eight hours submerged in water. These cubes, after being thus submerged from six to eighteen months. were tested by hydraulic pressure and the general results averaged from 400 to 1000 tons per square inch before crushing. The quantity of masonry originally estimated was 10,038,591 cubic feet, and the total amount actually executed was 11,030,000 cubic feet. During the working season on an average of from 9000 to 12,000 men were employed on the works. Before the work in connection with this scheme was started, the whole country for miles around was a dense forest and jungle almost uninhabited, and it was necessary before operations could be commenced to build a macadamized road a distance of eight miles. In order to induce native laborers to come on the works and remain there a regular village had to be laid out and built. A regular police force was established and retained at the expense of the contractors for the purpose of maintaining order, etc. Medical and sanitary arrangements for the village were carefully arranged and organized, and complete arrangements made for the proper care of the inhabitants in every way. Operations were begun in the summer of 1886, and it took five and one-half years to complete the work, which was accomplished on April 3, 1891, fifteen months before the time specified in the contract.

THE GREAT BOMBAY DAM.

A FAST COM POUND LOCOMOTIVE.—A compound locomotive recently built by the Baldwin Locomotive Works in Philadelphia is for the Philadelphia and Reading railroad. The engine is carried on eight wheels, four coupled wheels placed close together under the boiler, a two-wheeled truck forward and a pair of bearing wheels under the firebox. For fast work this makes a compact and easy running engine. The work done by this engine has so far been very good. At the present time it is employed in running trains 503 and 512 of the Bound Brook line between Jersey City and Philadelphia. On train 512 the distance of 85.1 miles between Wayne Junction and Jersey City is made in 98 minutes, or at an average speed of 52.1 miles per hour; there are no regular stops, but it is necessary to slow down at several junction and crossing points. On train 503 the time is not so fast, the 85.1 miles requiring III minutes, or an average of 46 miles an hour. On this trip, however, there arc four regular stops, so that the time, making allowance for them, is, after all, nearly as good. This is done in regular daily work. On May 13 the train drawn by this engine left Philadelphia seventeen minutes late, owing to some delay between Baltimore and that city. Several stops arc required before reaching Wayne Junction, but after passing that point the run was made at high speed. The entire distance—85.1 miles—from Wayne Junction to Jersey City was covered in 87 minutes, or at an average speed of 85.7 miles an hour. At one pirt of the run 10 miles were made in 7.55 minutes, or at the rate of 79.6 miles an hour. The train consisted ol four heavy cars, and there was un adverse wind blowing.

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