SPECIFICATIONS. 



213 





or on fillers, and their outstanding legs shall be not less than one-thirtieth of the depth of 

 er plus 2 in. 



80. Stays for Top Flanges. Through plate girders shall have their top flanges stayed at 

 rial of rvery tloorbeam, or in case of solid floors, at distances not exceeding 12 ft., by knee 



braces or gusset plates. 



TRUSSES. 



81. Camber. Truss spans shall be given a camber by so proportioning the length of the 

 members that the stringers will be straight when the bridge is fully loaded. 



82. Rigid Members. Hip verticals and similar members, and the two end panels of the 

 bottom chords of single track pin-connected trusses shall be rigid. 



83. Eye-bars. The eye-bars composing a member shall be so arranged that adjacent bars 

 shall not have their surfaces in contact; they shall be as nearly parallel to the axis of the truss as 

 possible, the maximum inclination of any bar being limited to one inch in 16 ft. 



84. Pony Trusses. Pony trusses shall be riveted structures, with double webbed chords, and 

 shall have all web members latticed or otherwise effectively stiffened. 



PART SECOND MATERIALS AND WORKMANSHIP. 



V. MATERIAL. 



85. Steel. Steel shall be made by the open-hearth process. 



86. Properties. The chemical and physical properties shall conform to the following limits: 



The yield point, as indicated by the drop of beam, shall be recorded in the test reports. 

 87. In order that the ultimate strength of full-sized annealed eye-bars may meet the 

 juirements of paragraph 163, the ultimate strength in test specimens may be determined by 

 ic manufacturers; all other tests than those for ultimate strength shall conform to the above 

 juirements. 



8. Allowable Variations. If the ultimate strength varies more than 4,000 Ib. from that 

 sired, a retest shall be made on the same gage, which, to be acceptable, shall be within 5,000 Ib. 

 the desired ultimate. 



89. Chemical Analyses. Chemical 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 the pouring of each melt of steel, and a correct copy of such analysis shall be furnished 

 to the engineer or his inspector. Check analyses shall be made from finished material, if called 

 for by the purchaser, in which case an excess of 25 per cent above the required limits will be 

 permitted. 



90. Specimens. Plate, shape and bar specimens for tensile and bending tests 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 |-in. for a length of at least 9 in., with enlarged ends. 



91. Rivet rods shall be tested as rolled. 



* See paragraph 96. f See paragraphs 97, 98, and 99. J See paragraph 100. 



