CAMBRIA STEEL. 



221 



STRENGTH OF STEEL COLUMNS OR STRUTS. 



For various values of in which L = length in feet and r = 



radius of gyration in inches. 



P = ultimate strength in Ibs. per square inch. 



FOR MEDIUM STEEL. 

 Square bearing Pin and square bearing 

 50 000 50 000 



p _ 



1 + 



(12 L)* 



P = 



1 + 



(12 L) 2 ^ 

 24 000 r 2 



P = 



Pin bearing 

 50000 



1 



(12 L) 



36 000 r 2 

 To obtain safe unit stress: 



For quiescent loads, as in buildings, divide by 4. 

 For moving loads, as in bridges, divide by 5. 



18000 r 2 



