Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

179 OF ENGINEERING FüKMULJS. American Truss Bridge—continued. The strain on toff at centre = is on the 8 D supposition that the diagonal bracing shown in the diagram is used, and that they are fixed to each other at the points of intersection. When the girder consists of a number of .separate tri- angles unconnected except by the top boom, the strain on the top boom will be uniform through- LS N2 —1 out, and = ,— ’ D 6 N2 Ikon Akchké» T — Strain at centre of arch. t — Strain at any point x. L = Total load on arch. I — Load between centre of arch and x. V = Versed sine. S = Span of arch. T = ^|. 4 = a/TH^ n V = 10 generally. n 2