The Architect and engineer of California and the Pacific Coast (1916) (14577075619)

How the "Snail-Shell" Stairway Gets Its Name — Looking Down Four Flights of Uninterrupted Concrete Spiral
Identifier: architectenginee4416sanf (find matches)
Title: The Architect & engineer of California and the Pacific Coast
Year: 1905 (1900s)
Authors:
Subjects: Architecture Architecture Architecture Building
Publisher: San Francisco, Calif. : Architect and Engineer Co
Contributing Library: San Francisco Public Library
Digitizing Sponsor: San Francisco Public Library



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terms used in defining consistency are altogether too indefiniteto the ordinary contractor. Consistency could probably best be definedby describing how concrete should act and the form it should take whendeposited. Until some form of apparatus is devised and a systematic method ofinspection established little can be done to overcome the present imsatis-factorv consistency specifications. Having concrete too wet should beespecially guarded against, since wet concrete gives a material inferiorin quality and strength to concrete of a medium or quaking consistency.Experiments with hydrated lime in concrete seem to indicate that it de-creases the percentage of voids, produces a more impervious concrete,reduces expansion and contraction imder moisture changes, and preventssegregation. In spite of the wonderful progress that has been made inconcrete work we are evidently still ver\ considerably in the dark as toits scientific preparation. The Architect and Engineer 97A Snail-Shell Stair
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The only spiral concrete staircase of its kind in the world has just been placed in the tower of the Southwest Museum in Los Angeles. Similar stairways exist elsewhere, as in the tower of St. Tauls and the tower of the cathedral in the City of Mexico, but they were built before the age of concrete. When viewed from above, its resemblance to the shell of a snail at once gave it a name. Says Irank Reed of that city, writing in The Engineering Record: It is, for its purpose here, an improvement over Sir Christopher Wren's masterpiece — the spiral stairway ascending the interior wall in the tower of St. Pauls Cathedral, London. The South-west Museum helical staircase is built inside a well in the center of the tower, thus not only preserving for shelves or mounted objects the entire interior wall-space of the tower, but also supplying on its own exterior wall additional space wh