Concrete Foundations.

Progress, Volume III, Issue 4, 1 February 1908, Page 135

Concrete Foundations.

Concrete piles are being used to replace timher piles in a large number of modern factories and other large buildings in America, and, to a less extent, in this country also. The reason is that concrete has the advantage of permanence and immunity from decay, while at the same time being comparatively cheap. In wet or filled-in areas where the ground water level is more than 6 ft. below the sujface of the ground, and the character of the soil is such that it is necessary to go still deeper for a suitable bearing stratum, a concrete pile foundation (says Carpentry and Building) is much cheaper than any other type of construction. Undei these conditions a solid masonry pier on a timber pile foundation would require, first, an excavation to below water level properly sheeted and braced. Second, driving of piles and cutting them off below the water level. Third, would be capping of the piles and building the solid pier to grade. Fourth, continuance of pumping through most of the operation. Fifth, baqkfilling the excavation. The whole constituting a long, tedious cpeiation, lasting seveyal days for each pier. In contrast to this, a pier of simplex concrete piles is built from the surface of the ground, no excavation being necessary except for the cap itself. An extra heavy pile-driver, especially equipped for this work, drives a hollow steel form of suitable length, 16 in. in diameter, and equipped with a special driving point to resistance. A small batch of 1 2 4 Portlarid cement concrete is then dropped into the feteel form, which form is raised about a foot by a pulling arrangement attached to the leads, and a heavy rammer dropped on the concrete. The effect of this impact is to open the jaws of the driving point and foice the concrete out of the pipe and into the adjoining soil. Another batch of concrete is then inserted, the form raised a short distance, and the concrete rammed. These operations are repeated until the form has been raised above the ground, and the space it occupied in the ground has been tilled with concrete. The time taken to instal one pile may run from fifteen minutes to one hour, depending on citcumstances. Twenty-eight piles 20 ft. long were driven, on a recent contract, by one machine in six hours. Thus a four -pile pier to support 120 tons can readily be built in one half a day, as against the time (several days) required by the other method. The Simplex concrete pile thus foi mcd of the same diameter throughout acts as a column, and ?lso develops a very great skin friction frcm the extreme roughness of its exterior surface caused by the ramming of the concrete into the surrounding material. The use of the Simplex concrete piles is increasing, not only in New York, but all over the States, and some installations have been made in England, Germany, and France. In some of the foundations built on Simplex concrete piles in New York City, the Building Department tested the piles with a loading of pig-iron amounting to 50 tons per pile without any settlement. In practice the piles are designed to carry 30 tons each.

The Russian Imperial Technical Society is preparing for an International Exhibition in December, 1908, of modern appliances for heating and lighting. The object of this Exhibition, which will last about two months, is to show the actual state of these appliances to the public and to determine their relative value. A congress of specialists will meet at the time of the Exhibition to study certain questions appertaining thereto. The Exhibition will comprise : Appliances for gas lighting, petrol, acetylene, gasoline, electricity, etc. ; portable heating appliances of all kinds ; various appliances for security against accidents caused by these methods of heating and lighting ; lastly, measurement instruments, meters, indicators, etc., for gas and electricity. If the exhibitors so desire the objects exposed may be submitted to the decision of a jury composed, partly, of persons elected by themselves. Medals issued by the State, ss well as medals and diplomas of honour, issued by the Societe Technique and others, will be awarded to the best appliances shown. The list of the members of the jury and the prizes ttey will award will be submitted for ratification to the Minister of Commerce and Industry. Articles sent to the Exhibition will enjoy a special tariff or the German, French, Austrian and Belgian railways. The same special tariff will rule on their return. Customs duties, which will have to be paid on the passing of the goods, will be refunded on their r eturn, provided the return is made within cne month after the close of the Exposition. In addition to the congress mentioned above, the Societe Imperiale Technique Russe intends to organise at the exhibition a series of technical and scientific conferences on the subjects of lighting and heating, accompanied by experiments and demonstrations.

The capital expended by the London County Council up to the end of March in the provision of accommodation for the working classes amounted to £2,498,000, z.vA housing has been erected for 41,602 persons. The sinking fund accumulated was £95,173, an increase on the previous year of £16,662. The gross rental for the year was £157,000, and the amount irrecoverable w?s only £396, or about 0-25 per cent. Loss of income from empties, however, amounted to £14,988, or 9.55 per cent, of the gross rental, against 9.45 in the previous year. But a large portion of this loss was in respect to dwellings which the Council was under statutory obligation to erect in order to provide for population displaced by improvements. ****** Mr. William Woodward, F.R.1.8.A., has been calling attention to the nuisance arising from the dust raised by housebreakers engaged in the demolition of old buildings. This could be avoided if the contractors would use water sprinklers during the demolition and clearing away of the debris, and Mr. Woodward proposes that the L.C.C. and other authorities should follow the example of the City Corporation in making such precautions against dust compulsory. The Corporation of London, he points out, have appreciated the mischief which arises from dust, and in the by-laws, clauses 3 and 4, they have made it an absolute condition that suitable screens or mats and the constant use of water shall be provided during the demolition of buildings in th'> city