Engineering Wonders of the World
Volume I

STEEL-FRAME BUILDINGS. 3 Fig. 6.—DIAGRAM ILLUSTRATING THE PROGRESSIVE INCREASE OF HEIGHT IN STEEL-FRAME BUILDING CONSTRUCTION. saving of weight that can be effected by the aid of steel framing. They show that the skeleton and cage systems —especially the latter—enable the engineer to obtain far more interior space on a given site than is permitted by the or- Floor Space— . dmary method or design. Lest any of our readers should underestimate the importance of this feature, we take as an ex- ample the case of a twelve-story office building 100 feet long and 50 feet wide. Without going into wearisome calculations, we simply state the result—that more than 4,000 square feet of floor space can be gained by substituting thin curtain walls and a steel cage for the regulation thick masonry walls. This means that twenty-four additional offices, each about 13 feet square (or its equivalent), could be secured, and without paying any more ground rent or buying additional land. Again, we may take a five- And Value g^ory building as the basis of incrccisccl * comparison. It is obvious that tho cost of land per floor is reduced by 50 per cent, for a ten-story building ; by 75 per cent. for a twenty-story building ; and so on. The practical results are that in America office and warehouse rents have been reduced by one-half, and that nevertheless property owners have doubled the return on their capital. Con- sequently the difficult problem of pleasing everybody has been solved, and it is not sur- prising that the height of steel-frame buildings has increased progressively in numerous Amer- ican cities. Fig. 6 will give some idea of what has been done in this direction within the last few years. American engineers admit readily that the credit for inventing the steel-frame system is really due to England, as the first edifice illus- trating the system was the magnificent iron-frame cage ^h®^rystal built by Paxton for the Exhi- bition of 1851, which still survives as the Crystal Palace. This building (Fig. 7) is a genuine cage structure, whose outer walls are Fig. 7.—PART ELEVATION OF CRYSTAL PALACE. AN EARLY EXAMPLE OF STEEL-FRAME CON- STRUCTION.' merely sheets of glass. As they had before them this convincing proof that an iron cage formed a perfectly stable and self-supporting structure, it is indeed strange that British