Concrete, its composition and use; a clear, detailed, complete statement of the fundamental principles of the basic process of the concrete industry, ... tables and data for the users of concrete

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909 Excerpt: ...about the question of design--especially as concerns the reinforcement. Practically all cracking of parts of concrete structures both at an early date and subsequently under heavy usage fall under this head. Early designers, failing to recognize the monolithic nature of the material, and thinking of it in terms of wood, brick, and steel rather' then in terms of itself, neglected to provide for many stresses with steel reinforcement. Some of these stresses--peculiar to the material--were fundamental and some unimportant. The fundamental ones were those existing over and approaching the supports, induced by the monolithic nature of the material. It was not sufficiently realized that with concrete there is no longer simple, isolated, disjointed action from support to support--as with timber and steel--but that action is continuous throughout the structure, and that if the design were not adapted to this continuity--of action, tensile stresses were going to be thrown upon the material in a place and manner with which it (un-reinforced) could not cope. The result was the development of cracks--some serious and all unsightly and undesirable--over and in the neighborhood of the supports. Many of the early structures (constructed 10 or 15 years ago, and even quite recently) evince faults of this kind, although nearly all are still carrying heavy loads. And several of the failures of concrete buildings within recent years, happily during the construction stage, were largely due to this lack. Notably the Bridgeman building in Philadelphia, which collapsed in 1907, and in which failure--in addition to utter lack of provision for stresses over the supports--there were manifested virtually all the faults peculiar to this class of work--the fruits, one and all, of ignora...