STRUCTURAL TABLES. 

 TABLE I. 



TOP CHORD SECTIONS. The top chord sections given in Tables 82 to 86 were calculated 

 to comply with the standard specifications which follow, unless otherwise noted in the tables. 



Specifications. All top chord sections shall comply with the following requirements. 



Thickness of Metal. The minimum thickness of metal shall be % in. for highway bridges 

 and % in. for railway bridges. 



Cover Plates. The cover plate shall have a thickness not less than one-fortieth (tg) the dis- 

 tance between gage lines of rivets in the flange angles on each side of the section. The cover 

 plate shall always have the minimum thickness that will comply with the above requirements. 



Web Plates. The web plates shall have a thickness not less than one-thirtieth (sV) the 

 distance between gage lines of rivets in the flange angles in the line of stress. As much of the 

 metal as practicable shall be concentrated in the web plates and flange angles. 



Proportions of Chord Section. There shall be a top cover plate which shall have a minimum 

 thickness permitted by the specifications. As much of the metal as possible shall be concentrated 

 in the web plates and flange angles. The top and bottom angles shall be so selected as to bring 

 the neutral axis of the section as near the center of the web plates as practicable. The moments 

 of inertia of the section about the two rectangular axes shall be approximately equal. 



