Creating Unisphere

Unisphere & crowds
 Unisphere - Largest representation of earth ever made

Unisphere -- the largest stainless steel structure in the world -- had quite a heritage to live up to.

Modern World's Fairs usually revolve around a symbol that captures the awe and imagination of all who see it. The Paris Exposition of 1889 had the Eiffel Tower; the 1939 New York World's Fair -- its Trylon and Perisphere; and the 1962 Seattle World's Fair -- its Space Needle.

To this spectacular line-up -- add the Unisphere -- one of the most inspiring and by far the most difficult and intricate of Fair symbols to design and construct.

Fair authorities wanted a model of the earth; an open sphere esthetically pleasing inside and out; from any angle and under any lighting. It had to convey the impression of lightness, grace, simplicity -- and yet had to be engineeringly sound to face possible wind forces up to 100-m.p.h.

The structure also had to resist corrosion since it will remain as a permanent feature of the park.

Problems? It was like balancing a beach ball on a golf tee!

Some 1,500 unknown factors had to be resolved to determine unit stresses. Complex modern buildings sometimes force planners to solve thirty to forty simultaneous equations. The Unisphere had six hundred and seventy just for one of three sets of calculations into which the problems were divided. The equations, which would take men years to solve manually, were fed into advanced electronic computers. With the aid of the computers -- which performed the necessary calculations in minutes -- the answer was obtained in a matter of weeks. Only steel -- stainless steel -- could do the job.

The engineering talent and experience of U. S. Steel's American Bridge Division -- the people who built such structures as the Empire State Building, the U. N. Headquarters, and most of the world's great bridges -- were put to the test.

Supports could not be placed according to expediency. They had to follow the parallels and meridians of latitude and longitude to retain the desired visual impression.

Where no known fabrication technique sufficed, engineers would invent one!

Land masses were built up in layer-cake style -- like huge contour maps conforming with the topography of each continent. The finishing touch was the addition of 3-ton orbital rings, representing the paths of man-made satellites now circling the earth.

The entire stainless steel structure rests on a 70-ton open sculpture of high-strength U. S. S. Cor-Ten steel, anchored by U. S. S. "T-1" constructional alloy steel bolts.

The Unisphere, made practical by modern computers, was made possible by modern steels and the ingenuity of American industry. Fair President Robert Moses -- at the start of construction of the Unisphere March 6th, 1963 -- said: "What stronger, more durable and more appropriate metal could be thought of than stainless steel?"

The gleaming symbol -- unforgettable in its majesty -- stands among other great industrial attractions that echo the invitation, "Come to the Fair," to see and thrill to the imagination of America's builders.

Source: United States Steel Press Release, March, 1965

Lookin up, into Unisphere

Photo Source: United States Steel 1963 Annual Report


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