Steel Chimneys for Mercantile Buildings.
Steel chimneys are being erected in connection with some of Chicago’s tall buildings. The Fair building has at present the tallest under construction. The chimney when completed, will be 250 feet high, being considerably higher than any other in the city, the highest at the present time being the one at the Gottfried Brewing Company’s plant at Archer and Stewart avenues, which is 175 feet. The outside diameter is 9 feet 5 inches, while the steel varies in thickness from at the top to ⅜-inch at the bottom. The lower 75 feet of the chimney is lined with fire brick 8 inches deep, formed 10 fit the shell compactly all around. Above this it is lined with hollow tile. This lining is supported at intervals of 25 feet by angle riveted to the steel shell; in other words, the chimney is lined in a manner similar to blast furnaces and foundry cupolas, and no expansion by heat can lessen its strength. The joints are all hot riveted. The steel shell is carefully protected from corrosion and from any attacks by the weather by painting inside and out. The weight of the chimney is spread to the foundations in the same general way as that of the columns of the building, the base or foundation on which it rests being constructed in the same manner. The ground is first covered with a layer of cement, then two layers of steel rails in cement and one layer of I-beams, on which the cast-iron shoe which takes the shell of the stack rests. The capacity of the chimney is 12 60-inch boilers 20 feet in length.
This is the first time this material has been used in the construction of the chimneys of mercantile buildings. The magnitude of the building and the necessity of economizing in space, the foundations for the columns occupying about all the ground, led the architects to adopt steel as the materia! for this purpose. Brick has been used almost entirely heretofore, but upon investigation it was found that the weight of a brick chimney of this size would be almost 700 tons, while of steel construction it would weigh, including the linings, a little less than 250. The outside diameter of the present chimney is 9 feet 5 inches, while, were it constructed of brick, it would be 16 feet 6 inches, thus making a great saving in space. Another consideration was the time consumed in construction. A brick chimney of this height, 250 feet above the sidewalk, should not be built faster than 2¾ feet a day on account of the settlement and the setting of the mortar, while of steel it can be erected at the rate of 20 feet a day. Another important consideration is that it costs only about 60 per cent of what a brick chimney would cost. Steel has been used in the construction of chimneys for iron mills and factories.—Am. Gaslight Journal.