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Capital Projects:

Tower Impact Strengthening

The background to this scheme is that is has been recognised that there is a risk that the main towers could suffer an impact from an errant HGV resulting in structural damage. 

Recent work carried out by the Highways Agency in England has re-evaluated the loads that can be applied by an errant HGV impacting on highway structures, recommending that they be doubled in specific instances. 

The existing barriers at the towers are the original construction and would be ineffective in protecting the towers against the new impact loadings. However, it should be noted that as far as can be ascertained these new loads have not yet been incorporated in technical memorandum.

It must be stressed that the risk of this type of collision occurring has a low probability and no reports of this type of incident occurring at towers on other bridges in the UK or elsewhere in the world have been uncovered. 

Flint and Neil, consulting engineers, have been engaged to carry out a study to look at the possibility of strengthening the towers locally and upgrading the existing barrier.  From the initial evaluation it appears that due to the geometry, and the capacity of the towers and adjacent deck, only a limited amount of additional protection to the towers could be installed.

Given the above, this scheme is being reviewed and a further report will be brought to the Board in the near future.

The Bridge:

Facts & Figures

Opened 1964, 2.5 km long, Main span 1006 metres
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  • Roadworks on bridge both directions (20:04 BST 22/07/14)