368 SPECIFICATIONS 



Aggregates. The sand shall be clean, and not contain over 

 3% of loam. Broken stone and gravel shall be hard and 

 close-grained, and free from dust and dirt; they shall be of 

 such size as to pass through a ring 1 in. in diameter. 



Reinforcing Steel. The steel for the reinforcement shall 

 be manufactured by the open-hearth process. This steel 

 should have an ultimate tensile strength of from 60,000 to 

 70,000 Ib. per sq. in. and an elastic limit of at least half that 

 amount, with an elongation of at least 20%. A bar shall 

 bend cold through an angle of 180 and close down on itself 

 without showing signs of fracture. High-carbon steel or 

 steel with an elastic limit greater than 45,000 Ib. per sq. in. 

 shall not be used. 



The beam and girder reinforcement shall consist of square- 

 twisted or approved type of deformed bar, while the slab 

 reinforcement may be of square-twisted bars, deformed bars, 

 or of an approved form of expanded metal or woven or 

 electrically welded wire fabric. The column rods may be 

 of plain round or square-twisted bars. The girders and 

 beams must have the rods so bent and arranged as to provide 

 amply for the bending moments throughout their length and 

 also to take care of the negative bending moments near the 

 bearings and supports. Sufficient stirrups must be provided 

 near the bearings or throughout the length of the beams and 

 girders to resist the horizontal, oblique shearing, and tensile 

 stresses. 



Floor and Test Loads. The floors and columns throughout 

 shall be designed to sustain a live floor load of 150 Ib. per 

 sq. ft. The finished floor systems shall be tested in two 

 places, to be designated. The test load shall be equal to 

 one and one-half times the amount of the live floor load. 

 The test loads shall be so placed as to fully load the girders 

 and beams of one bay. 



