"The Hershey Arena... Tedesko designed a thin reinforced concrete, barrel-shell roof, three and one-half inches thick, supported across its width by eight arches. ...A roof posed a different problem than a bridge or dam. On a bridge, live load from traffic is significant, and a dam must resist the live load of water on its upstream face. On a long-span concrete roof, live load (mainly rain and snow) is a small fraction of the dead load of the structure itself. Tedesko realized that the supporting arches did not need to be of uniform depth. ...[he] designed the arches to be able to... support the entire roof load, including the thin shell and all of the live load. He also made calculations to show that the thin shell could carry its own weight and the live load without help from the arches, except near their lowest edges. It was thus a conservative design..."