Science, Maths & Technology

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Tay Bridge disaster

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# 4.7 Photographs showing the detail: damage to pier 1

The final example of a partly collapsed pier is pier 1, photographed from the base of pier 28 and shown in Figure 32. Fracture damage to the flange at the top of the second tier is visible on the east-most column (top right); a large chunk of metal has broken off. The southern column (right of centre) exhibits a matching fracture where the parts are still held in position by the wrought iron strut. Propagation of the same crack has also released the top lug, with the tie bar and strut still attached, so they hang in the centre of the pier.

Figure 32 Pier 1, looking north, showing two upstanding tiers of columns and damage to column flanges

The damage overall is more severe than in the case of pier 3, but it is still possible to identify the pattern of fracture to the principal components. The second picture of pier 1 is shown in Figure 33: a view of the platform looking west towards the western columns. The image has been made lighter and the contrast increased to highlight parts lying on the platform and their fracture surfaces.

Figure 33 Fractured parts of pier 1 on the platform, looking west

## Question 5

Summarise and explain the damage to the principal parts of pier 1 visible on Figures 32 and 33, above. Be careful to survey the picture systematically, including any interesting features that might help to clarify how failure of specific components occurred. Distinguish between wrought iron and cast iron as the material of construction for those various parts you include in your survey. Include a comparison of the damage here with that visible on similar parts of pier 3.