The possibility of repairing the current structure was explored during the early stages of the Option Study process, prior to considering the replacement of the structure.
The structural form of the bridge, as well as its current condition, are prohibitive factors to undertaking effective structural repairs without replacing the structure as a whole. The bottom flanges of the transverse elements of the structure have deflected due to corrosion (refer to image 1). Replacing these elements would require the dismantling the inner deck apart from the main structural beams due to the configuration of the structure.
The main structural girders’ bottom flanges also present significant corrosion (refer to image 2). Due to the location and spacing of the rivets plate, bonding would not be effective to strengthen these elements and these beams would also require replacement.
In addition to the severely corroded steel beams, both abutments have large cracks from top to bottom (image 3 and 4). The north-east wingwall has also cracked and separated away from the abutment (image 5).
The rivets that give the structure its distinct look also prevent options to strengthen or effectively repair without the dismantling and replacing the entire deck.
Once these considerations were taken into account, the replacement options for the structure were included in the Option Study. Subsequent studies reflected this knowledge and also aim to address the additional issues that were being raised locally at the adjacent junction due to the tight highway space which has been a contributory factor in reported road traffic collisions.
For these reasons Boxted Bridge is deemed to be unviable for repair, and it would be uneconomical to do so. Investigations conducted during the feasibility study stage determined the replacement option was the best possible solution once it was established that repairing the existing structure was no longer considered a viable option.
The outcome concluded by Cleveland Bridge UK Ltd in May 2021, who were commissioned by Essex Highways to carry out an independent assessment report, was that a replacement bridge should be the preferred option.
The bridge was constructed in 1897 and is nearing the end of its natural lifespan, as can be seen by the visual deterioration on the structure. Proposals are being considered for replacing the structure as a long-term solution, with inspections to monitor the condition of the structure increased from every two years to every six months in the meantime.