Democratic Sentinel, Volume 15, Number 27, Rensselaer, Jasper County, 24 July 1891 — THE LEANING TOWER. [ARTICLE+ILLUSTRATION]

THE LEANING TOWER.

A Proposed Building to Illustrate- Engineering skill Some mouths ago a proposition wasmade to the Worlu’s Fair Directory to build a leaning tower as one of the attractions for 1893. There have been many inquiries as to what the projector of the tower proposed to do, and we publish his own description of the proposed building. This engineering novelty is a massive tower having an elevation of 225 feet, about 70 feet square, and boldly leaning 100 feet from the perpendicular. The entire structure is of metal, principally steel, weighing about 500 tons above foundation, and of novel cantilever construction that affords all requirements of stability. It will be built to safely sustain a load of 160,000 pounds on floor of the story. The framework is of steel truss construction, forming a large cantilever of enormous strength and ligidity, which combines for support a superstructure of metal. The accompanying diagram, showing truss and foundation, will readily explain the principle of construction. It will be observed that the tower frame and superstructure as a whole resemble the letter L, making in principle an immense unyielding L, of which the lower part acts as a foot or offset to counter the lean of superstructure. Depth of superstructure, 48 feet; area, 165x115 feet. The construction of foundation is chiefly of plate-riveted

iron girder work imbedded in concrete, which forms a solid bed about eighteen feet deep. This girder-concrete foundation has the characteristics of being continuous in structure and rigid throughout, and is especially designed for building on yielding substrata, such as the deep clay of Chicago. On the girder-work there are bolted steel bearing plates, and on these plates the massive truss foot of the cantilever rests. This foot at left side will be attached to metal parts of bed by large steel pins and eye-bars, but these connections will not be brought into play unless the tower is heavily loaded. In the superstructure three lines of trusses constitute the main supports, two from sides of tower, the third has a middle position, and a lateral truss system braces them together. The walls of the tower are comparatively light, being simply a framing of small-sized aDgle-iron attached to the trusswork, aad having a facing of embossed sheet metal. The exterior will be painted a dark terracotta color. At Bologna, Italy, there is an old tower called the Garisenda. It is 130 feet high, eighteen feet square, and eight feet out of plumb. A better known tower of this character is the Campanile of Pisa. It was built in the twelfth century, and is a stone structure fifty feet in diameter, 179 feet high, and leans thirteen feet out of perpendicular. The leaning of this tower was due to a poor foundation while building; the tower had but reached one-third of its intended height when the foundation of one side began to sink and incline the work. The masonry was then strengthened with iron clamps which have kept the structure intact. By this accidental departure from the builder’s aim, what at first might have been a poor reflection of his work, made the tower of Pisa famous. In building the cantilever of L tower for exhibition purposes it will make the greatest leaning structure in the world and be unique in many particulars. Besides affording an attractive sight for visitors it will present a novel display of the application of metal to all building purposes. It will take eight months to build this structure, which includes shop work and erection. The cost will be about $5,000,000.

THE LEANING TOWER.