Art. 89. 



POINTS OF CONTRARY FLEXURES. 



141 



It is sometimes con- 

 venient to imagine a beam 

 having points of contra- 

 flexure, to be made up of 

 beams simply supported at 

 their ends and cantilever 

 beams. There being no 

 moment at the points of 

 contra-flexure, the cutting 



FIG. 93. of the beam at these points 



does not affect the stresses, provided the loads or reactions at 

 these points are taken equal to the shear at these points. This is 

 illustrated in Fig. 93 for the case of a beam fixed at both ends. 

 This resolves the case of Fig. "99 into those of Figs. 96 and 94. 



