Engineering Wonders of the World
Volume I

REINFORCED CONCRETE CONSTRUCTION. 431 fittings to be added presently of postal matter and live load. Only 18 inches square on the ground floor, they are reduced to 9 inches in the topmost story. At the east and west ends of the main block the walls overhang the foundations con- siderably—at the east end by 12 feet 6 inches— being held up by immense longi- tudinal beams of 147 feet span, themselves sup- ported by a num- ber of cantilever beams forming continuations of the floor beams of the second story. Despite the enormous load, the settle- ment of these beams, after the wooden supports used during con- struction had been withdrawn, proved to be ab- solutely nil. The time occu- pied in actual construction was eighteen months. But for certain difficulties, quite apart from the system (the Hennebique) used, this period might have been curtailed considerably. So far as raising walls and columns was concerned, progress was regulated mainly by the rate at which the moulds and centerings could be placed in position. One notable feature of ferro-concrete con- struction is its great simplicity. The only Fig. 35.—REINFORCED WATER-TOWER, NEWTON-LE-WILLOWS. {Photo, Messrs. L. G. Mouchel and Partners.) materials needed were gravel, sand, Portland cement, steel bars, and the timber for the moulds. The carpenters led the way, making and fixing the moulds. Behind them followed the concreting gangs, who laid in their proper positions the col- umn and beam reinforcing steel rods, and round them rammed the concrete care- fully. The last was composed of one cubic yard of Thames ballast broken to pass through a f-inch mesh, to half a cubic yard of sand and 6 cwt. of Portland ce- ment, with a due addition of water. Highly - skilled labour was not needed here, as né» girders had to be ri vetted. Altogether, a- bout 3,000 tons of steel were used on this con- tract. Had steel girders and stan- chions been em- ployed, the weight of metal would have risen to 15,000 tons, and the total weight of the struc- ture from 33,000 to 70,000 tons. The offices as they stand are a monolith—that is to say, there is not a joint anywhere. From the topmost chimney to the lowest column footing, the. concrete forms one con- tinuous whole—a gigantic box pierced with openings for nearly three thousand windows.