Elasticity and Strength of Materials Used in Engineering Construction Section V

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Excerpt from Elasticity and Strength of Materials Used in Engineering Construction Section V: Economic Theory of Steel Railroad Bridge DesignThe reduction in cost through reduced weight is enlarged by the use of fewer joints reduced field riveting simplification of the joints by the uni formity of the sections. Reduction 0 the. Number of different ieces to handle, thereby simplifying and reducing the cost of shop work an erection.Economic bridge design is so far removed from an exact science that the ideas of what should be the weight of long sim li(' spans varies between di¿'crent engineers from 50 to 100 percent. As in icated by the discussion Trans. Am. Soc. C. E. 1922, page 9135, where Mr Steinman states his. Careful estimate of a sim lo 775-foot span based on detail calculations of all sections under the A. It. A. Specifications shows a weight per lineal foot. Of pounds, while the writer estimates the weight of two similar spans at half that amount. Mr. Lindenthal in the same. Paper believes a two-span con tinuous truss saves 20 percent over two simple spans, whereas the author figures that the continuous truss spans are 40 percent heavier than two simple spans should be.This divergence in weight is not to he. Wondered at when we consider the A. R. E. A. Specification in its broader aspects, to wit: The. Depth of trusses shall not be less than one-tenth of the span, Art. 51. Art. 12, panel lengths shall not exceed l'/2 times the width center to center of trusses. Now the economic proportions for even the 200~feet through span are 2542 times as great as the limitations of this specification.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.