FOOTBRIDGES AT LIVERPOOL.
457
Detailed drawings of the bridge are exhibited in figs. 446, 447, and
448.
Footbridges at Liverpool.
Illustrations are given of two types of footbridge—the first constructed
in wood, and the second in iron. The wooden bridge (figs. 449, 450, and
451) which has a total length of 73 feet 6 inches, spans an opening of 50
Figs. 449 and 450. —Footbridge at Liverpool. Scale—16 feet = 1 inoli.
Fig. 451. —Footbridge at Liverpool. Seale—4 feet = 1 inch.
feet. The width of the footway is 4 feet, and in order to accommodate the
ballast the bridge is widened at the tail end to 8 feet 2 inches over all.
The ballast is composed of concrète laid in the floor and in the side panels.
Movement is made entirely by hånd. The iron bridge (figs. 452, 453, and
454) has a length of 96 feet, and covers an opening of 60 feet. It is
propelled by hydraulic power, by means of rack and pinion gearing on the
underside of the bridge floor. The bridge was tested as a cantilever with a
uniformly-distributed load of 7| tons.