15 



Table V. — Safe loath, in pound.*, for tongleaf-pine (Finn* pcUustris) beams uniformly 



loaded, and 1 inch in width, 



[For other species multiply those loads by the ratio of the safe modulus of rupture for the species as 

 given in Table IV, divided by 1,550. Thus, for shortleaf pine these loads should be multiplied by 



,'- r .,- For other widths, multiply by the width. For single load in middle of beam, divide these 



loads by 2. To avoid danger of shearing along the neutral plane, the ratio of length to height of 

 uniformly loaded beam should be at least 10; for beam with single load in middle, not less than 8.] 



where 



Safe-load formula. 



Uniform load, S=i Rblfi 



■At 



Single load in middle, S= 



2 R b It? 

 31 



R=modulus of rupture. (See Table IV.) 

 S=safe load in pounds. 

 b= breadth of beam in inches. 

 /i=height of beam in inches. 

 Z=length of beam in inches. 



Deflection formula. 



Uniform load, &-- 



Single load in middle, A 



5RIJ 

 24 E h 



Rl* 



GKh 



A=deflection at center in inches. 



E =mouulus of elasticity. (See Table IV.) 



Other quantities same as for safe-load formula. 



Tabic V gives the safe load on longleaf-pine beams, uniformly loaded 

 and 1 inch thick. By a uniform load is meant a constant load per run- 

 ning foot of beam. 



