6 BOVBY ON SHEAR PEODUCED BY LIVE LOAD. 



assuraiug that the weights are collected at the pauel points, and that the distance of 

 transfer is a pauel length, 



I — a^ first r panels 



I total number of panels. 



Similar results may be obtained when the chords are not horizontal. For example, 

 consider a diagonal between the r"" and the (r+1)"' weights, iu the case of a truss AB, in 

 which only the lower chord is horizontal. 



Let the corresponding panel length of the upper chord produced meet the lower 

 chord produced in the point C. 



Let CA = h. 

 " p be the perpendicular from C upon the diagonal in question. 

 " i2], i?2, be the reactions at A duo to the first and second distributions, respectively. 

 " -D^, I>2, be the corresponding diagonal stresses. 



Suppose, for simplicity, that no weights either leave or advance upon the girder. 



. • . Mil = wfii+ .... +?('„«„. 



I)jP=^MJi — w^{h-\-l — a) — .... — iv,.(h+l — «,.). 

 Ii.,p = w^(a,+o;)+ .... w„{a„-{-x'). 



D2P =: B-z.h — w,{h+l — flj — x) — . . . — w,{h-\-l — (7,. — x) . . . — iv,-+iifi+l — a,.+i — x) 

 . . . —ic,+,j{h+l — ar+g — x). 



Hence, Z)i > < D.,, according as 



x(iVi+W2+ . . . +w,-\-io,.+i+ . . . w,+g) + w,.+i(h+l — a,+i)+ . . . -\-Wr+,j{h-\-l — a,.+,j) 



><{S2—iiiyh, 



h 



or a:(F;.4-r)+^',X^+/0 > < W„-x-, 



I 



R'.j{t+h) being the algebraic sum of the moments of the weights transferred with respect 



to a 



If no weights are transferred, this relation reduces to 



h I ' 



