ROEBUNG FLOOR 



293 



of i-io to y% the span. Tests have shown that the steel work in ex- 

 panded metal floors is not ordinarily affected by the cinder concrete. If 

 care is used when erecting the floor to coat the expanded metal with a 

 coating of Portland cement mortar before the metal has become rusted, 

 the protection against corrosion will be almost perfect. 



Roebling Floor. The floor shown in (c) Fig. 144 consists of a 

 wire cloth arch, stiffened by woven-in stiff steel rods $ to i-inch in 

 diameter, at about 9-inch centers, which is sprung between the floor 

 beams and abuts on the seat formed by the lower edge of the floor beam. 



"BUCKEYE" FIREPROOF FLOORING. 



MULTIPLEX STEEL PLATE FLOOR 



(a) 



(b) 



Roebling Fire-proof System 



rc) 



FIG. 144. 



(d) 



On this wire centering Portland cement concrete is filled in and is fin- 

 ished with a wearing coat of cement or a wooden floor as shown. The 

 beams are held in position by 24 or J^-inch tie rods, placed from 4 to 



