64 MOVING LOADS ON BEAMS 



Now S 1 will be greater than 5* 2 if PI L is greater than W a, or if 



The criterion for maximum shear at any point therefore is as 

 follows : 



The maximum positive shear in any section of a beam occurs when 



D T 



the foremost load is at the section, provided W is not greater than l - 



P T 



If W is greater than ^ , the greatest shear will occur when some 



succeeding load is at the point. 



Having determined the position of the moving loads for maxi- 

 mum moment and maximum shear, the amount of the moment and 

 shear can be obtained as in the case of beams loaded with stationary 

 loads. 



