SPECIFICATIONS FOR PLAIN AND REINFORCED CONCRETE. 273 



11. Chemical Analyses. Clu-mical determinations of the percentages of carbon, phosphorus, 

 sulphur and manganese shall be made by the manufacturer from a test ingot taken at the time 

 of tlu- pouring of each melt of steel, and a correct copy of such analysis shall be furnished to the 

 fii^iiu'i-r or his inspector. Check analysis shall be made from finished iu.iti-ri.il, if railed for liy 

 tin- railroad company, in which case an excess of 25 per cent above thi- required limits will be 

 allowed. 



12. Form of Specimens. Plates, Shapes and Bars: Specimens for tensile and bending 

 tests for plates and shapes shall be made by cutting coupons from the finished product, which 

 shall have both faces rolled and both edges milled to the form shown by Fig. i; or with both edges 

 parallel; or they may be turned to a diameter of J in. with enlarged ends. 



13. Bars shall be tested in their finished form. 



14. Number of Tests. At least one tensile and one bending test shall be made from each melt 

 of steel as rolled. In case steel differing f in. and more in thickness is rolled from one melt, a 

 test shall be made from the thickest and thinnest material rolled. 



15. Modifications in Elongation. For material less than ^ in. and more than } in. in thick- 

 ness the following modifications will be allowed in the requirements for elongation: 



(a) For each -fa in. in thickness below ^ in. a deduction of 2\ will be allowed from the speci- 



fied percentage. 



(b) For each \ in. in thickness above \ in., a deduction of i will be allowed from the specified 



percentage. 



16. Bending Tests. Bending test may be made by pressure or by blows. Shapes and bars 

 less than one inch thick shall bend as called for in paragraph 8. 



17. Thick Material. Test specimensone inch thickand over shall bend cold 1 80 degrees around 

 a pin, the diameter of which, for structural steel, is twice the thickness of the specimen, and for high 

 carbon steel, is six times the thickness of the specimen, without fracture on the outside of the bend. 



1 8. Finish. Finished material shall be free from injurious seams, flaws, cracks, defective 

 edges or other defects, and have a smooth, uniform and workmanlike finish. 



19. Stamping. Every finished piece of steel shall have the melt number and the name of 

 the manufacturer stamped or rolled upon it, except that bar steel and other small parts may be 

 bundled with the above marks on an attached metal tag. 



20. Defective Material. Material which, subsequent to the above tests at the mills, and its 

 acceptance there, develops weak spots, brittleness, cracks or other imperfections, or is found to 

 have injurious defects, will be rejected and shall be replaced by the manufacturer at his own cost. 



21. Reinforcing steel shall be free from excessive rust, loose scale, or other coatings of any 

 character, which would reduce or destroy the bond. 



WORKMANSHIP. 



22. Unit of Measure. The unit of measure shall be the cubic foot. A bag containing not 

 less than 94 Ib. of cement shall be assumed as one cubic foot of cement. Fine and coarse aggre- 

 gates shall be measured separately as loosely thrown into the measuring receptacle. 



23. Relation of Fine and Coarse Aggregates. The fine and coarse aggregates shall be used 

 in such relative proportions as will insure maximum density. 



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