Cornbrook

Cornbrook Structure Assessments

ESL carried out a series of surveys to the viaduct to determine the extent of the corrosion issues which had been identified and to fully dimension and understand the nature of the problems being experienced. The defects identified during the inspection included severe corrosion and section loss, deteriorated protective coating, spalled masonry and open joints.
Following the surveys, we produced a detailed survey report and a quantitative Form BA assessment of five of the structures. This assessment involved producing a detailed model of the structures and all the loads acting in STAAD Pro. Using the model, we carried out calculations in accordance with both historic standards from the early twentieth century and modern-day Eurocode methods.
Unfortunately, our calculations indicated that strengthening works were required to the structures. We therefore followed up our Form BA with an Option Selection Report which detailed the different strengthening options available to the RAM team with the advantages, disadvantages and risks of each. We presented our findings to the Network Rail team over a series of workshops which succeeded in driving engagement with the poor condition of the structures and assisted the OLE teams with structural understanding of their assets.
We are particularly proud of the collaborative manner in which we approached this project. On carrying out the Form BA assessment, we initially identified that the structures were not fit for purpose and recommended to Network Rail that they be replaced. However, following a collaborative process with the structures and OLE RAMs, it became apparent that there was not budget to carry out this replacement in the short term. In order to assist in managing the asset safely, we therefore identified a more limited scope of works that could be carried out and that would prevent any catastrophic failure of the structures. Taking this approach involved an understanding of the principles of asset management and prioritising the problems that we found rather than providing a purely engineering assessment that was not achievable within the constraints that were faced by our client.

Project Description

The overhead line structures between Manchester Piccadilly and Trafford Park are approximately eighty years old and were showing signs of severe corrosion, with certain structures having been highlighted as at particular risk. This project was undertaken to identify the magnitude of the problems with the structures and identify possible remedial works.