ARCHES 



55 



structed with CD =-. This is shown by the area surrounded 



y 

 by heavy lines in Fig. 36a. 



U L{H *- 



3 4\L 6 ___ .__ai,_ d ._^, w , 



^p^ran^tL > 



it = distance frcjm led support to the load}. 



Tang^-1 Tang 2 -^ Tang0,-f 



FIG. 366. DIAGONAL U,U 

 FIG. 36. 



The expression for H is 



*-** 



This indicates that fl" varies directly as the distances of the 

 load from the supports and hence the influence diagram 



