Notice that simply fixing the ends of a beam reduces 

the bending moment by a factor of two to three. The 
graph to the right shows that M_{max} is the greatest in 
the middle of a uniformly loaded, simply supported 
beam since this is the farthest point from the supports. 
From there it gradually reduces to zero at the ends, 
which can rotate slightly and thus do not experience a 
bending moment. Of course a beam can be loaded

Fig. 144  Bending moment 
nonuniformly which will affect the bending moment. 
diagram of a uniformly loaded, 
Only beams loaded in the middle or uniformly are 
simply supported beam 
treated in this lesson since they are the
simplest cases. 
