300 SUPPLEMENT TO CHAP. XTV. [CHAP. 



From the exact formula above we have the following tables. 

 VALUE OF M 00 . 



VALUES OP B AND O. 



Here, as always, a negative moment denotes tension in lower or inner 

 flange. We see at once from the table that the maximum compression in 

 this flange at crown does not occur for full load, but for load extending 

 from both ends towards the crown as far as about 8 ths of the span or $tha 

 of the half span. Within the middle half of the arch, then, a load any- 

 where causes tension in lower flange at crown outside of this middle half 

 a load anywhere causes compression in the lower flange at crown. For 

 ;vrge central angles, K may be disregarded, and we have simply M = M o. 



