MATERIALS AND WORKMANSHIP 49- 



being twisted, the hot-rolled bars shall meet the require- 

 ments of the structural-steel grade for plain bars shown 

 in this specification. 



197. Number of Tests. At least one tensile and one bending 

 test shall be made from each melt of open-hearth steel rolled, 

 and from each blow or lot of ten tons of Bessemer steel rolled. 

 In case bars differing f in. and more in diameter or thickness 

 are rolled from one melt or blow, a test shall be made from the 

 thickest and thinnest material rolled. Should either of these test 

 specimens develop flaws, or should the tensile-test specimen 

 break outside of the middle third of its gauged length, it may 

 be discarded and another test specimen substituted therefor. 

 In case a tensile-test specimen does not meet the specifications, 

 an additional test may be made. 



The bending test may be made by pressure or by light blows. 



198. Modifications in Elongation for Thin and Thick Material. 

 For bars less than ^ in. and more than f in. nominal diameter 

 or thickness, the following modifications shall be made in the 

 requirements for elongations: 



(a) For each increase of J in. in diameter or thickness above 



f in., a deduction of one shall be made from the specified 



percentage of elongation. 

 (6) For each decrease of ^ inch in diameter or thickness 



below ^ in., a deduction of one shall be made from the 



specified percentage of elongation, 

 (c) The above modifications in elongation shall not apply 



to cold-twisted bars. 



199. Number of Twists. Cold-twisted bars shall be twisted 

 cold with one complete twist in a length equal to not more than 

 12 times the thickness of the bar. 



200. Finish. Material must be free from injurious seams, 

 flaws, or cracks, and have a workmanlike finish. 



201. Variation in Weight. Bars for reinforcement are subject 

 to rejection if the actual weight of any lot varies more than 5 

 per cent over or under the theoretical weight of that lot. 



WORKMANSHIP 



202. General. All parts forming a structure shall be built 

 in accordance with approved drawings. The workmanship and 

 finish shall be equal to the best practice in modern bridge works. 



