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

½FG² × EF = LA
RL × GA × m;

whence

FG = √(2GA × LA
EF × RL × m).

The following table has been calculated for the use of builders and engineers, giving the thickness of abutments for different spans and heights.

255. THICKNESS OF RECTANGULAR ABUTMENTS.
	Semicircular arch.				Basket-handle arch.
	The height being.
Span.	5	8	10	15	5	8	10	15
6	3	3	3¼	3½	3½	4	4	5
8	3½	4	4¼	4½	4	4½	5¼	6
10	4	5	5	5	4½	5¾	6¼	7
15	4½	5¼	5½	6	5	6½	7¼	8
20	5	5½	6	7	6	7¼	8	9
25	5½	6	6½	7¼	7	7½	8¼	9½
30	6	7	8	8½	8	8½	9¼	10
35	6½	7	8¼	9	9	9¼	10	11
40	7	7½	8¾	9½	9½	10	11	12
45	7½	8¼	9¼	10	10	10¾	11½	12½
50	8	9	10	11	10¼	11½	12¼	13

Fig. 121.       Fig. 121 B.

Fig. 121 A.

256. The form of a bridge abutment will depend upon the locality and upon the use to which the bridge is to be put, whether used for a railroad, or for common travel; whether near a large city, or in a location where appearance need not be regarded. Where a river acts dangerously upon a shore, wing walls will be necessary. These wings may be curved or straight, and may be simply the abutment produced, or may be swung around into the bank at any required angle, until the winged abutment, as in figs. 121, 121 A, 121 B, becomes the U abutment, fig. 124; or by moving the walls, W and W, parallel to themselves, takes the form of the T abutment, fig. 122.