342 



PLATE GIRDER PORTAL. 



Art. 170. 



From Eq. (183) 



/? 1 = i[4,450(20-0.87) 4- 9,900] = 11,880 

 R / = i [5,550(20 - 3.06) + 16, 130] = 13,770 



From Eq. (186) 



Stress in '=8,750 + 11,880=20,630 Ibs. 

 From Eq. (187) 



Horiz. Comp. 'F = 10,000 + 11,880 + 13,770 =35,650 Ibs. 

 From Eq. (188) 



Stress in FF' =5,550 + 13,770 = 19,320 Ibs. 



Maximum stress in the posts occurs at F', but this comes 

 under case No. Ib. 



For connections see remarks under Case Xo. la. 



170. Case No. 2. Plate Girder Portal. \ 



Case No. 2a. Posts Fixed Top and Bottom. In this case 

 i(#+P)a. 



From equation (118) 



e=0 anda=c and 



From equation (106) 

 H=H'=y 2 (R+P) 

 From equation (122) 



From equation (126) 



= i-(B+P) (a+d-xj 



Bending moment in 



the posts at a, a', F and 



Fig. 220. (Case No. 2) 



d(R+y 2 P)dH(a. 

 BB^l=.(R-\-y 2 P)d+y i (R-{-P)a-Vx. 



The maximum stress 

 in the posts is at F' and 

 is found from equation 

 (135). 



To find the stresses 

 in the girder take any 

 section Im, with the cen- 

 ter of moments at m. 



