No doubt the Clifton Bridge trustees would be able to identify the weakest part of the bridge to meet David Neale's request to keep the bridge open for crowd loading (NCE last week).
In about 1960 I was part of a team at Bristol University who tested the original end under road wrought iron cross beams, when Clifton College asked that the bridge axle load be increased to allow the school bus to cross to the playing fields on the far side.
The test terminated prematurely, when the test rig failed. Eventually it was shown that the wrought iron beams were in excellent condition.
In practice the cross beams were shallow riveted trusses with deep chords so that some of the shear was carried by the chords.
Much later I was part of another team that devised a method for repairing the eyes of the wrought iron tie bars connecting the links to the plate girders alongside the road.
Using a helical spread of weld metal inside the eye it was possible to fuse to the iron between the layers of oxide and build up several weld layers. The hole was then drilled to the original dimension.
John Jubb, Tanglewood, Barton, BH25 5PW