Fig. 214 shows an arched rib used in the construction of the vaulted roof of the South Park Conservatory, Chicago, 111. This building is a steel and glass structure about 417x58 feet in extreme dimensions and 31 ft. in greatest height. It consists of a rectangular centre pavilion and two rectangular end pavilions with connecting wings 115 ft. long and 39 ft. wide. Fig. 213 shows a plan of one of the end pavilions and a portion of one of the connecting wings. The arched rib shown by Fig. 214 is one of the ribs shown in plan at F, F. These ribs were spaced about 7 ft. 8 ins. apart. The rafters or curved ribs, H, H, of the end pavilions are built in a similar manner to those at F, but their tops are connected by a horizontal top chord section, 10 ft. 4 ins. long, field riveted to them. The ribs H, H, were built of 4-3 1/2x2 1/2x3/8 -inch L's, with 2"x5/16" lacing. The diagonal ribs, K, K, were built to the curve formed by the intersection of the vaulted sides. These ribs are 15 inches deep, and the members are of the same size as those used in the ribs H, H. The entire covering of the building is of glass. Details of the ribs H and K, were published in the Engineering Record for Dec. 24, 1898.
Fig. 217. Detail of Supporting Brackets.
Fig. 218. Detail at A, Fig. 215.
Mr. D. H. Burnham was the architect of the building and the steel work was designed and constructed by the Kenwood Bridge Co., Chicago.
Figs. 215 and 216* shows a section and plan of a ceiling dome in the Appellate Court House, New York City. This dome is supported by a circular plate girder 24 5/8" deep, and 30 ft. 8 ins. in diameter, to which sixteen solid web radial brackets are attached, which carry the framework of the dome. The dome itself is built of curved T-bars, arranged as shown by the quarter plan, Fig. 216, with a circular ring formed of a 5"x3 1/2"x 3/8" L at the bottom of the ribs and another near the top formed of a 6-inch bent channel. Details of the supporting brackets, and of the connections to the upper ring are shown in Figs. 217 and 218.
*Redrawn from illustrations in the "Engineering Record" of April 14, 1900.