238 



FIRE-BOX GIRDER STAYS. 



and this is the Board of Trade equation — 



750 X ^3 X f 

 (TF-P) xDx WPxL 



in which the constant factor c = 750 for girders with two 

 supporting bolts. 



Next we have the case of the 



GIRDEH WITH THREE SUPPORTING BOLTS. 



yy 



Then assuming that the length of the girder, and the total 

 weight supported by the bolts, remains the same as in the 

 two previous cases, then the "Moment of Rupture" at the 

 centre of the girder will be equal to 



M = 



^w X jZ X iZ . ^w x^lxU ^iv x^lx^l 



I 



+ 



I 



M = 



UcxU^ . \io>^tI^ ^wx^l^ 



I 



+ 



I 



+ 



I 



-AT _1VXI IV Xl XV xl 



24 12 



24 



24 



M = 



IV xl 



