FARM STRUCTURES 



409 



one inch wide with loads uniformly distributed. If the load 

 be concentrated at the center, divide by two. 



For oak or Northern yellow pine, the tabular values may 

 be multiplied by 1%; for Georgia yellow pine, by 1%. 



For a discussion of the materials used in the construction 

 of farm machinery, see Chapter XXXI. 



Safe Load in Pounds for White Pine or Spruce Posts.* 



Size of post 



Length of post in feet 



in inches 



8 



10 



12 



14 



16 



4x4 ... 



4x6 



b}4 round. 



6x6 



6x8 



6x10 



1}4 round. 



8x8 



8x10 



8x12 



9J4 round. 



10x10 



7,680 



11,520 



12,350 



19,080 



25,440 



31,800 



24,220 



35,450 



44,320 



53,180 



40,000 



62,500 



7,033 

 10,550 

 11,730 

 18,216 

 24,290 

 30,360 

 23,380 

 34,300 

 42,480 

 51,450 

 39,000 

 55,400 



6,533 



9,800 

 11,180 

 17,352 

 23,140 

 28,920 

 22,540 

 33,150 

 41,440 

 49,730 

 37,860 

 53,960 



8,700 

 10,490 

 16,490 

 21,980 

 27,480 

 21,660 

 32,000 

 40,000 

 48,000 

 36,800 

 52,520 



15,620 

 20,830 

 26,040 

 20,820 

 30,850 

 38,560 

 46,240 

 35,730 

 51,080 



Oak and Norway pine posts are about one-fifth stronger, 

 and Texas pine and white oak are one-third stronger. 



Stone. Limestone and sandstone are the kinds of stone 

 generally used for building purposes. Granite is used to a 

 limited extent. Limestone is the most common stone used, 

 and when dense and compact is very durable. It often con- 

 tains certain substances which cause the stone to become 

 badly stained after being in use for a time. Limestone has 

 an average compressive strength of about 15,000 pounds per 

 square inch and weighs from 155 to 160 pounds per cubic foot. 



♦Kidder's Pocket Book. 



