CONCENTRATED LOAD STRESSES 



53 



Wind Load 

 Rollers Windwi 



point of intersection of the vertical reaction R r and the line drawn 

 through o parallel to the closing line of the equilibrium polygon, with 

 the lower end of the load line. 



Since the vertical components of the reactions are independent of 

 the conditions of the ends of the truss, the vertical components of the 

 reactions in Fig. 33 and Fig. 34 are the same. It will be seen that the 

 load PI produces stress in the members of the truss with rollers wind- 

 ward. If the line of action of R 2 drops below the joint P 5 the lower 

 chord of the truss will be in compression, as will be seen by taking 

 moments about P 5 . 



Concentrated Load Stresses. The stresses in a Fink truss due 

 to unequal crane loads are calculated by graphic resolution in Fig. 35. 



The reactions were found by means of force and equilibrium poly- 

 gons. The truss is reduced to three triangles for the loading shown. 

 The solution of this problem is similar to that for ceiling loads in Fig. 



