The 50,000 seat Busch memorial stadium in St. Louis combines the dimensions of a Roman coliseum with a suggestion of airy grace. This is achieved by the 96 circling arches which crown the building, the pattern of the half-suspended columns which surround the stadium. The two outer circles of columns support the highest (seventh) level which (like the sixth) was cast in place. The underside of this top level has a bold architectural pattern made with a great ring beam mold. To set and move the forms used here, a self-propelled vehicle was constructed to move on I-beam tracks suspended by cable from the surrounding columns. To place and move the arched roof forms set between each girder, a large carrier on wheels moving on the deck directly beneath the roof was contrived. It was raised and lowered by hand powered jacks at each of the four corners. The roof shell is 5 inch thick concrete weighing 110 pounds per cubic foot.