Handbook of Railroad Construction; For the use of American engineers. / Containing the necessary rules, tables, and formulæ for the location, construction, equipment, and management of railroads, as built in the United States.

by George L. Vose

Fig. 63.

Let d b represent the weight; e h shows the tension. The triangles a c d, and a b e, are similar; as also e b h and d b c; whence

b e = a b, c d
a c, and e h = c b, b e
d c = tension.

In practice place w for b d; i. e. the actual weight.

In this plan, if the chord is able to resist the cross strain between A and D, it will also resist the tension. This cross strain is found by the formula already given and illustrated.

174. From what precedes, we have the following dimensions for bridges such as are shown in figs. 61 and 62. The details of 62, at f and c, and at E, 61, are shown in figs. 62 A, 62 B, and 61 C.

Fig. 62 A.

Fig. 62 B.