CHAP. Xra.] . ANALYTICAL FORMULA. 



MOMENTS AT SUPPORTS OF LOADED SPAN. UNDJORM LIVE LOAD 



OVER ANY SINGLE SPAN. 

 Coefficients of to P given in triangle. 



,, , 153 x4- 41 571 , 



Thus for seven spans, ^^ _ _ = ^, and so on. 



The triangle above gives the moments for uniform load over any 

 span, both right and left. For left supports we have simply 

 to count the span from right to left. Thus for seven spans for 

 load in the sixth span from left, we have moment at left-hand 



627 

 support = - w Z 2 , counting the spans from left to right in 



triangle. For the moment at right support of same loaded 

 span, we count six the other way from right to left, and find 

 571 

 1165 "* 



139. Moments at Supports of Unloaded Spans. The 

 triangle and formulae above give the moments at the supports 

 of the loaded span only, both positive that is, always tending 

 to cause tension in upper flange and compression in lower. 



If m represents the number of any support counting from 

 the left, the moments at any support generally may be found 

 by the following formulae : 



When m<r + l, M m = 1 



* 



When m>r, M^ = 1 w P 



If we make in these formulae m = r in the first, and m 



