L-iy 



Light Box 



UJ 



Dim 



Area 



Y 



AY 



Light Box 

 2' X 4' 



1, 152 



60 



69, 120 



Z-1/2" (6 

 steel pipe 



180 



36 



6,480 



2-1/2" ^ 

 steel pipe 



180 



36 



6, 480 



SA = 1, 512 



SAY = 82, 080 



2-1/2" (6 steel pipe 



Prob: Find load per in which will produce yielding of post at base. 

 Assume: 



S 



I post 



ID 



OD 



C 



^D 



y 

 y 



M 

 M 



p 

 p 



V 

 V 



= 30 KSI 



= 1.18 in4 



= 2.468 



= 2.875 



= 1.437 



= 0. 35 



SA 



y 



82, 080 



SA 



1,512 



54.2" 





SI 



(30,000) (1. 18) 



1. 437 



= 24, 600 in-lb 



M 24,600 



y 2A (54. 2) (1512) 



43. 2 Ib/ft^ 

 (2) (43.2) (32.4) ^ 

 (.35) (64) 



11.2 ft/sec 



54. 2' 



3 lb/in 



11. 2 ft/sec 



Figure 222 Calculation of wave force required to bend a light box 

 normal to the plane of the diagram. (from Tudor, I96U) 



346 



