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. The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world. ms of structures usuallybuilt of iron or steel and steel and masonrycombined. It is well known that the averagelife of iron or steel railroad bridges is about 20years at the most, while a great many deterio-rate rapidly under the influence of heavy traffic,atmospheric conditions, and the effects fromgases from the locomotives, and have to be re-placed in a much shorter time; but, althoughthey cannot compete in durability with masonrystructur
. The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world. ms of structures usuallybuilt of iron or steel and steel and masonrycombined. It is well known that the averagelife of iron or steel railroad bridges is about 20years at the most, while a great many deterio-rate rapidly under the influence of heavy traffic,atmospheric conditions, and the effects fromgases from the locomotives, and have to be re-placed in a much shorter time; but, althoughthey cannot compete in durability with masonrystructures, the cheapness of iron and steel ren- in designing any one of these forms oftrusses the calculations may be grouped accord-ing to their application, to the web systemcomposed of the upper and lower chords, thevertical and end posts, the suspenders and themain and counter diagonals; to the floor sys-tems ; and to the lateral bracing and sway brac-ing. It is not practicable to give in this articledetailed descriptions of the various memberscomposing those systems, but Fig. 34 is intro-duced to show the complete details of a 100 foot «—iTtr.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectencyclo, bookyear1908