Americas first thin-shell barrel roof: A world record-holder

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    Europeans, in particular the Germans, had been designing and building thin-shell concrete roofs since the early 1900s. But the first fullscale one built in the United States captured the world’s record as the largest barrel-shaped shell roof on its opening day in 1936—the Hershey Sports Arena in Hershey, Pa. This reinforced concrete facility came about through a series of unlikely and fascinating events.

    A daring, young, Austrian-born, German-trained engineer, Anton Tedesko (1903-1994), had been sent to the United States specifically to introduce thin-shell construction into the Western Hemisphere. The German company he worked for—Dyckerhoff and Widmann (D&W)—was worldrenowned for designing and building complex reinforced-concrete structures.

    It already held several patents for the design and construction of thinshell designs.

    In 1932, D&W aligned with a wellestablished Chicago consulting engineering firm, Roberts and Schaefer (R&S), to promote its shell designs in the United States. As part of the deal, 29-year-old Tedesko was put in charge of the German-United States joint venture’s shell-building program in America.

    Although R&S made and promoted many designs, few were built initially because the nation was still in the grips of the Great Depression and construction was slow. It wasn’t until the joint venture obtained a commission for the Brook Hill Farm exhibition at the 1933 "Century of Progress" World’s Fair in Chicago that one of its designs was built, yet then demolished right after the fair closed.

    The joint venture’s first permanent concrete shell was the Hayden Planetarium in New York in 1934, a small 81-foot-wide, 3-inch-thick hemisphere.

    Two years later it engineered the largest barrel-shell structure the world had ever seen—the Hershey Sports Arena. When it opened on Dec. 19, 1936, its 3-1/2-inch-thick shell had an arch span of 222 feet and a rise of 81 feet.

    It was stiffened at 39-foot intervals by massive, two-hinged arch ribs. A lot of skepticism preceded this accomplishment, yet the residents of Hershey proudly tagged it a "homemade structure, constructed by Hershey men," and local history is rich with details as to why.

    By the early 1930s, the number of hockey-loving residents in Hershey far exceeded the capacity of all area venues.

    In 1936, candy magnate Milton Hershey solicited plans to build a new, large ice rink. He had high hopes that this construction project would also boost an economy suffering from high unemployment.

    One of Hershey’s associates contacted the Portland Cement Company in Chicago and its people put Hershey in touch with R&S. On Jan. 21, 1936,R&S submitted plans for a huge concrete structure. At first, Hershey was skeptical about its practicality, but its innovative design excited him. He gave his approval with these caveats: only local workers and materials were to be used, and no out-oftown contractor or construction manager could be hired. As a result, R&S’s Tedesko ended up being the project’s planner/designer/architect/engineer/ construction manager.

    Once final drawings were completed, Tedesko employed Oscar Spancake, a local carpenter-foreman. He mobilized a crew of 250 men, four concrete mixers, and two elevators. The workers had no previous experience in concrete construction, which required the young Tedesko to supervise all aspects of the construction constantly.

    Workers placed the first concrete for the arena’s roof shell on July 2, 1936. Its formwork was made up of a patchwork of standard lumber sizes because Hershey had stipulated that all the lumber used had to be reused later to construct barns and homes in the town.

    Concrete placements started simultaneously from the bottom on both sides of the shell, and didn’t stop until the two sides came together at the top. Each 39- foot-wide section took 14 to 20 days to complete based on 24-hour working days. Workers placed concrete even when temperatures dropped to freezing.

    To keep the uncured concrete from freezing, they packed horse or cow manure around it.

    Once the first roof section was placed and cured, its forms were slowly lowered, first at the crown and then toward the sides. Local powers-that-be expected the whole massive structure to come crashing down.

    Much to everyone’s relief, the concrete shell held firm, with each subsequent section completed more skillfully than the previous one.

    The engineering significance of Hershey Arena has forever been etched in engineering history books.

    Richard Weingardt, P.E., is CEO and chairman of Richard Weingardt Consultants, Inc., a Denver-based structural engineering firm. He can be reached via e-mail at editor@gostructural.com.