II OF COVER PLATES 17 



m th. moment of the external force* moment of 



internal stresses 



Kur -0) -P,(x -6) +etc. -SA, . (4) 



in which e\vry juantity U known e\eept i. 



To apply this to any point n between the first con- 

 c -lit rated and the end the above becomes 



irj- 

 - 



in which A', and N/ui are known, and the solution of w 



18 a inplr matter. It should IH- tinted that tin- 



proper position for the live load Ls that which makes RI 



.\inium. 



To apply it to any point q between two loading |* 

 the formula IH 



. . . . 



The position of tin live load inti-t be taken, 6*1*1,80 

 as to make the U-ndin^ moment at /', a maximum; seeond, 

 80 as to make the U-n-lini: moment at /' a a maximum. 



Thi> L'iv- tu< i-.|uations of the form of (4") each of 

 \vhieh mu.-t IN- >olvei| for x. 



The value of .r, which is least, i.e., the one requiring 

 tlu longest cover, i- to be taken. 



The lengths of rover plates are rtadily found by a 

 graphic method which needs no explanation U-yond the 

 following .sketch: 4c. The full line is drawn to n j.rvaent 



