HOMOGENEOUS BEAMS 



147 



The first of the following tables gives the properties of 

 standard I beams. The bevel on the inside of the flange 

 is always made 1 to 6. The same bevel is also used for 

 channels. 



The tables dealing with I beams and channels give two 

 columns dealing with the deflection, or sag, of beams. The 

 use of these columns will be explained on page 174. The 

 other values given in the tables will be readily understood. 



FIG. 6 



Frequently, steel beams are built up of several steel sec- 

 tions riveted together. To find the strength of a beam of 

 this kind it is first necessary to determine the moment of 

 inertia of the entire section about its neutral axis. This is 

 done by the methods previously described on page 97, but 

 it may probably be best illustrated by an actual problem. 



