HEAVY TIMBER 



Table H. Table of Safe Loads in Pounds Uniformly Distributed for 



Timber Beams. 



Limited by Resistance to Horizontal Shear Along the Neutral Axis. 



(Actual size) 



Horizontal Shearing Stress in Pounds 

 per Square Inch 



6x12 



8x12 



10x12 



12x12 



6x14 



8x14 



10x14 



12x14 



14x14 



6x16 

 8x16 

 10x16 

 12x16 

 14x16 

 16x16 



6x18 

 8x18 

 10x18 

 12x18 

 14x18 

 16x18 

 18x18 



20x20 



5y 2 xiiy 2 

 7y 2 xiiy 2 



9%xll% 

 Ili/ 2 xliy 2 



71/2x131/2 



9y 2 xi3y 2 



I3y 2 xisy 2 



9y 2 xl5i/ 2 

 Il%xl5% 



I3y 2 xi5y 2 

 I5y 2 xi5y 2 



9y 2 xi7y 2 



I5y 2 xi7y 2 



17%xl7% 



8432 

 11500 

 14566 

 17632 



9900 

 13500 

 17100 

 20700 

 24300 



11366 

 15500 

 19634 

 23766 

 27900 

 32032 



12834 

 17500 

 22166 

 26834 

 31500 

 36166 

 40832 



10540 

 14375 

 18207 

 22040 



12375 

 16875 

 21375 



25875 

 30375 



14207 

 19375 



24542 

 29707 

 34875 

 40040 



16042 

 21875 

 27707 

 33542 

 39375 

 45207 

 51040 



12648 

 17250 

 21849 



26448 



14875 

 20250 

 25650 

 31050 

 36450 



17049 

 23250 

 29451 

 35649 

 41850 

 48048 



19251 

 26250 

 33249 

 40251 

 47250 

 54249 

 61248 



14756 

 20125 

 25490 

 30856 



17325 

 23625 

 29925 

 36225 

 42525 



19890 

 27125 

 34359 

 41590 



48825 

 56056 



22459 

 30625 

 38790 

 46959 

 55125 

 63290 

 71456 



16864 

 23000 

 29132 

 35264 



19800 

 27000 

 34200 

 41400 

 48600 



22732 

 31000 

 39268 

 47532 

 55800 

 64064 



25668 

 35000 

 44332 

 53668 

 63000 

 72332 

 81664 



50700 63375 76050 88725 101400 



(Courtesy Southern Pine Association, New Orleans, La.) 



NOTE To use table for values of the horizontal shearing stress less than 

 100 pounds per square inch, multiply the safe load in the 100 column by the ratio 

 of the unit stress used to 100. For example: For 85 pounds per square inch, use 

 .85 of the load in the 100 column. 



Two formulas which are used widely are given below. The 

 first is the result of work done under the supervision of the 

 Division of Forestry, U. S. Department of Agriculture, and 

 is what is known as a "curved line formula." The second is 

 a formula proposed by Mr. Benjamin E. Winslow, Mem. Am. 

 Soc. C. E., and is of the "straight line" type. The Winslow 

 formula is used to quite a considerable extent in practice and is 



Page sixty-four 



