294 FLOORS 



r 



6 feet apart. The concrete is commonly composed of I part Portland 

 cement, 2.y 2 parts sand and 6 parts clean cinders, and is laid with a 

 thickness of not less than 3 inches over the crown of the arch. The 

 weights and safe loads for floors constructed on this system are given 

 in the manufacturer's catalog. 



The Roebling Construction Company also makes a floor with flat 

 construction as follows : A light framework is made of flat steel bars 

 set on edge and spaced 1 6-inch centers, with %-turn at both ends 

 where the bars rest on the steel beams ; braces of half round iron are 

 spaced at intervals to brace the bars. The Roebling standard lathing 

 with ^4 -inch steel stiffening ribs woven in every 7^2 inches, is then 

 applied to the under side of the bars and laced to them at each inter- 

 section. On this wire lathing cinder concrete from 3 to 4 inches thick 

 is deposited. 



"Buckeye" Fireproof Flooring. The steel flooring shown in (a) 

 Fig. 144 is manufactured by the Youngstown Iron & Stetl Roofing Co., 

 Youngstown, Ohio. This floor is made in two sizes, one for bridge 

 floors and the other for building floors. The flooring shown in (a) is for 

 buildings, is made in sections of four triangles each in lengths 

 up to 10 feet, and will lay a width of 21 inches. Each triangle is 5^4 

 inches wide and 2^2 inches deep. The flooring when complete with a 

 concrete filling and a 1^2 -inch wearing surface will weigh from 32 to 

 35 pounds per square foot. The weights of the metal troughs laid in 

 place are given in the following table : 



WEIGHTS OF METAL TROUGHS 2^ INCHES DEEP BY 5% INCHES WIDE, 



INCLUDING SIDE LAPS. 

 GALVANIZED TROUGHS. BLACK IRON TROUGHS. 



No. 16386 Ibs. per 100 square feet. No. 16363 Ibs. per 100 square feet. 



No. 17350 " " " " " No. 17327 " 



No. 18313 " " " " " No. 18290 " 



No. 19278 " " " " " No. 19254 " 



No. 20241 " " " " " No. 20218 " 



No. 22204 " " " " " No. 22181 " 



No. 24168 " " " " " No. 24145 " 



