Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

178 JIOTÆSWORTH S POCKET-BOOK American Truss Bridge. L = Total load distributed. N = Number of panels or bays. W = — = Load at each point of suspension. S = Span. A Xj __ (Distance of any point of suspension from BXJ ( abutments A and B. R = Length of tension rod. r = Length of counter-tension rod, D = Depth of trass. • WLA. X R Strain on tension rod R = —-—— x —. • W R X Strain on counter-tension r = —-----—- . 8 Strain of perpendicular strut = W. SL 81)’ Strain on top at centre The thick lines are in compression. The fine lines are in tension. D is usually . [For continuation see next page.]