CHAPTER XVIII. 



CORRUGATED STEEL. 



Introduction. Corrugated steel is made from sheet steel of stand- 

 ard gages, and is either galvanized at the mill or is left black. The 

 black corrugated steel is usually painted at the mill and is always paint- 

 ed after erection. Paint will not adhere well to the galvanized steel 

 until after it has weathered unless a portion of the coating is removed 

 by the application of an acid. The common standard for the gage of 

 sheet steel in the United States is the United States Standard Gage, 

 and this should be used in specifying the weight and thickness. The 

 thickness and weights per square of 100 square feet, for black and gal- 

 vanized sheet and corrugated steel are given in Table XV. The weights 

 of the corrugated steel given in the table are for standard corrugations, 

 approximately 2.^/2 inches wide and ^ of an inch deep. If black sheet 

 steel is painted, add about 2 Ibs. per square. 



TABLE XV. 

 WEIGHT OF FLAT, AND CORRUGATED STEEL SHEETS WITH 2^2-iNCH 



CORRUGATIONS. 



Corrugated steel is also made with corrugations 5, 3 and 

 inches wide approximately. Corrugated steel with corrugations 



