236 



PRACTICAL STRUCTURAL DESIGN 



Fig. 158 Braced Cantilever with Concentrated Load 

 at End 



The reactions are computed as follows, for the truss shown, 

 R = (300 X 36) + 600(30 + 24 + 18 + 12 + 6) = 36Q() ^ 



18 



which is equal to the total load on the truss, therefore the truss 



is exactly bal- 

 anced on the 

 support at joint 

 5. The author 

 has examination 

 capers in which 

 this roof truss 

 appears with 

 supports at the 

 two ends and 

 also at the right 

 end and (in 

 turn) each ver- 

 tical, which 



gives four different combinations. Some of the problems require 



the wind load to be computed while others assume all loads as 



vertical. With four different ways 



to support the truss, with and 



without wind and these various 



conditions varied by varying the 



amount of vertical load at each 



joint it is readily seen why ex- 

 aminers like this truss. Students 



preparing for architects' license 



examinations should work it with 



a number of changes in all the 



conditions. 



Fig. 158 represents a braced 



cantilever carrying a single con- 

 centrated load at the end. The 



dead load is neglected and the 



frame therefore is weightless. 

 Fig. 159 represents a braced 



cantilever with a load at each 



joint. This illustrates the general method for dealing with 



cantilever trusses. On the truss diagram the loads are shown 



Fig. 159 Braced Cantilever 

 Loaded on Joints 



