Art. 134. 



STRESSES IN A WHIPPLE TRUSS. 



257 



Here, as in the half-hip truss, the slope of the end diagonals 

 is only half that of the intermediate ones and this must be re- 

 membered in writing the chord coefficients and in using them. 



The center post is similar to the center post of the Pratt 

 truss with an even number of panels (Fig. 184) ; it has two con- 



Fig. 188. 



ditions affecting the stress. When the counter is acting as 

 shown 



. L., 



but when the bridge is symmetrically loaded, the counter will 

 not be in action, and 



The first case will usually govern in a through bridge. 



135. Stress Coefficients for a Double-intersection 

 Warren Truss. The double-intersection truss of Fig. 189 (a) 

 is treated as a deck structure. Whether or not there are joints 

 at the intersections of the web members, the stresses are statically 

 indeterminate according to equation (8), Art. 42. Upon the 

 usual assumption of two independent trusses as shown in Figs. 

 189 (b) and (c), the stresses are statically determinate and the 

 final stresses in the chords are equal to the sums of the stresses 

 in these two trusses. 



