GRAPHIC STATICS 



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A form of truss used for exhibition halls, drill halls, etc., is 

 shown in Fig. 144 with Whipple framing of web members, and 

 in Fig. 145, with the web members framed as in a Warren truss. 



Fig. 144. Crescent Roof Truss. Whipple Framing. 



On the load line the loads are set off vertically to scale and from 

 each point a line is drawn parallel with the top chord. The loads 

 being symmetrical it is really necessary to draw but one-half of 

 the force diagram. With trusses having as complicated a fram- 

 ing as these curved, crescent shape trusses, it is difficult to trans- 

 fer all the lines from the truss diagram to the force diagram and 

 have them truly parallel. In such cases it sometimes pays to 



Fig. 145. Crescent Roof Truss. Warren Framing. 



compute the angles of slope by trigonometry and set the lines 

 off with a protractor or by using a table of chords. 



The hog-back truss shown in Fig. 146 is in common use and 

 sometimes the upper chord is curved instead of straight. No 

 difficulty should be encountered in obtaining the stresses in such 



