Arch Roof

One having curved tru es without visible tie rods, so that the walls of the building are apparently subject to a lateral thrust. A groined roof is formed of two arched 364 ft. span, and that of the Liberal Arts building of the Chicago Exposition of 1893 a central span of 368 ft., the largest arch roof ever built. IMG:content-0248.png:[graphic] IMG:content-0249.jpg:[graphic]