Exploring Telford

Site contents © Richard Foxcroft 1996-2002

Cound Arbour Iron Bridge, 1797

© Richard Foxcroft, August 2000

The bridge is formed from three ribs, a plated underside to the arch and the roadway. The original roadway is either missing or hidden under a modern concrete deck.

The outer ribs of the bridge are formed of two iron arches of different radii...

...and a horizontal top beam which carries the modern concrete road deck. The railings, though, appear to be the originals.

Cracks in the ribs have been repaired by bolting on plates.

The legend Cast at Coalbrookdale 1797 appears at the apex of the bridge.

The lower arch rests on a plate the width of the bridge...
...to which they are jointed.
The plate has a lip or sill over the edge of the stone, but where the stone is eroded you can put a finger in behind the lip and feel the bottom of the plate.
The upper arch also rests on a plate, which rests on a chamfer (?) cut in the stonework at the appropriate angle.
The three ribs are strengthened by a tie-bar, which is jointed, not bolted, to the outer ribs.
The inner rib, normally unseen, is plain and functional compared to the decorated outer ones.
The tie-bar is jointed to this also. The bolts in this photo support a plate fitted to repair the crack which can be discerned below the second bolt.
The plates which form the underside of the bridge rest on a ledge on the upper arch of the outer ribs, and are bolted to it (look closely in the shadow) and to each other...
..and to lugs on the middle rib.
The ribs are cast in halves and bolted together at the apexes.
The whole assembly can be made out here, with care: three ribs, two plates, tie bar, plates which form the arch.
Cound Arbour Br. Finite Element Analysis (large)
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