. Spons' dictionary of engineering, civil, mechanical, military, and naval; with technical terms in French, German, Italian, and Spanish . places with the greatest ease, and form the face ofthe wall under water. Behind this facing hydraulic concrete is lowered under the water in largeboxes having movable bottoms, and is discharged in mass to form the body of the wall. To confinethis at the back before it has set, loose rubble stones are deposited and carried up simultaneouslywith it. The hearting of the pier, consisting of hard till, stones, and gravel, is deposited after-wards, and the whole
. Spons' dictionary of engineering, civil, mechanical, military, and naval; with technical terms in French, German, Italian, and Spanish . places with the greatest ease, and form the face ofthe wall under water. Behind this facing hydraulic concrete is lowered under the water in largeboxes having movable bottoms, and is discharged in mass to form the body of the wall. To confinethis at the back before it has set, loose rubble stones are deposited and carried up simultaneouslywith it. The hearting of the pier, consisting of hard till, stones, and gravel, is deposited after-wards, and the whole carried up to the level of low water. The entire mass, piles and stone facing, concrete backing and hearting, is allowed to consoli-date for a sufficient time ; after which the heads of the iron piles and the granite facing blocks arecapped at the level of low water by a granite blocking or string course, and the upper portion ofthe walls is carried up in freestone, ashlar, and rubble. The remainder of the hearting betweenthe walls is then filled in, and the whole is finished with a granite coping and causeway. The 6 B 1842 HAEBOUE. 1843 walls are 33 ft. in height from the foundations, 11^ ft. thick at the concrete base, and they diminishto 5 ft. thick at the top. Particular care is taken with regard to the hydi-aulic lime. It is burnt at the quarries, but isbrought from thence in the shell by the railway in covered wagons, so as to preserve it from is ground at the harbour works, for which purpose, and for mixing the mortar, there have beenerected four vertical double-roller mills and two sieves, driven by an engine of 20 horse-power. In the part of the pier which has been already executed, the stone facing under low waterbeing made to slip into the groove formed by the flanges of the iron piles, the outer flange is leftexposed to the action of the salt water, which no doubt will in the course of time exert an injuriouseffect upon the iron, Figs. 3878 and 3881
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Keywords: ., bookcentury1800, bookdecade1870, bookidsp, booksubjectengineering
