The New York Subway - Its Construction and Equipment by Anonymous
page 43 of 199 (21%)
page 43 of 199 (21%)
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are the systems of terra-cotta ducts in which the electric cables are
placed. The cables can be reached by means of manholes every 200 to 450 feet, which open into the subway and also into the street. The number of these ducts ranges from 128 down to 32, and they are connected with the main power station at 58th and 59th Streets and the Hudson River by a 128-duct subway under the former street. [Sidenote: _Reinforced Concrete Construction_] The reinforced concrete construction substitutes for the steel roof beams, steel rods, approximating 1-1/4 inches square, laid in varying distances according to the different roof loads, from six to ten inches apart. Rods 1-1/8 inches in diameter tie the side walls, passing through angle columns in the walls and the bulb-angle columns in the center. Layers of concrete are laid over the roof rods to a thickness of from eighteen to thirty inches, and carried two inches below the rods, imbedding them. For the sides similar square rods and concrete are used and angle columns five feet apart. The concrete of the side walls is from fifteen to eighteen inches thick. This type is shown by photographs on page 41. The rods used are of both square and twisted form. [Illustration: LAYING SHEET WATERPROOFING IN BOTTOM] [Illustration: SPECIAL BRICK AND ASPHALT WATERPROOFING] [Sidenote: _Methods of Construction |
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