9) consists of a steel braced tower, on which revolves a large horizontal double cantilever; the forward part of this cantilever or jib carries the lifting crab, and the jib is extended backwards in order to form a support for the machinery and counter-balance.
The Taff is spanned by two bridges, one a four-arched bridge rebuilt in 1858-1859 leading to Llandaff, and the other a cantilever with a central swinging span of 190 ft.
There are two high-level footways for use when the bascules are raised, the main girders of which are of the cantilever and suspended girder type.
- Typical Cantilever Bridge.
(e) Cantilever Bridges.
The exceptional local conditions at the site of the Forth bridge led to the adoption there of the cantilever system, till then little considered.
The length of the cantilever bridge is 5330 ft., made up thus: central tower on Inchgarvie 260 ft.; Fife and Queensferry piers each 145 ft.; two central girders between cantilevers each 350 ft.; and six cantilevers each 680 ft.
This is due to the half weight of centre girder, the weight of the cantilever itself, the rolling load on half the bridge, and the wind pressure.
(4) The Red Rock cantilever bridge over the Colorado river, with a centre span of 660 ft.
21 shows a typical cantilever bridge of American design.
The girder spans are 525 ft., the cantilever spans 547 ft., and the shore spans 201 ft.
The central double cantilever is 360 ft.
The cantilever rests on two river piers 120 ft.
The counterweight is a depressed cantilever arm 12 ft.
Since the erection of the Forth bridge, cantilever bridges have been extensively used, and some remarkable steel arch and suspension bridges have also been constructed.
The great cantilever bridges have been erected in the same way, and they are specially adapted for erection by building out.
58, 5 q and 60 show an independent girder, a cantilever, and a cantilever and suspended girder bridge.
The cantilever and suspended girder types are as economical and free from uncertainty as to ' ??` the stresses.
In long-span ¦ bridges the cantilever system permits erection FIG.
Farther down the river are two railway bridges, the Michigan Central's cantilever bridge, completed in 1883, and the (lower) single steel arch bridge (completed in 1897, on the site of John A.
The Pasig river is crossed by two modern steel cantilever bridges.
The river is spanned here by a cantilever railway bridge 1895 ft.