390 NOTE TO CHAP. XIV. [APPENDIX. 







91. Arch hinged nt Apex and at the Extremities of the 

 centre Line; Flanges A being retained, and only II re- 

 moved. The method of solution is precisely the same as 

 before, the only difference being that the span is now 175 ft. 

 instead of 170.6, and the rise 25 ft. instead of 29.5. The reac- 

 tions and thrust will then be somewhat different. Thus, for 

 the left abutment A, 



P 1 = 0.71, P 2 = 1.42, P 8 =2.14, P 4 = 2.85, P 6 = 3.57, 

 H i: =2.48, H.,= 4.97, Hs = 7.5, H 4 = 9.97, H 5 =12.5, 



P,= 4.28, P 7 = 5.00, P 8 = 5.72, P 9 = 6.43, P 10 = 7.15, etc. 

 H, = 14.98, H, = 17.5, Hg = 14.98, H 9 = 12.5, H w = 9.97, etc. 



We have therefore the following table : 



