The team at RAB recently completed a Residual Life Assessment (RLA) of Hamilton Wall, a 500m stretch of the Lowestoft sea defences in Suffolk. RLA’s are engineering evaluations that estimate the remaining service life of structures based on their current condition and operating history.
The work included a visual assessment and material testing of the sea wall, as well as defining the different compositional elements of the asset. The OBCAM method was used to conduct the visual inspection. This method split into their constituent elements with each element given a weighting depending on its importance regarding asset function. Elements with critical importance have a weighting of 9, whereas elements with minimal importance have a weighting of 1. Each element is then assigned a grade from 1-5 with 1 being ‘very good’ through to 5 being ‘very poor’ condition. The weightings are multiplied by the element grade and then divided by the sum of the weightings to get an overall asset score.
The continual high sea level and rock armour revetment in front of the wall make it impossible to safely inspect the sheet pile toe. To account for this there are over 80 inspection chambers along the length of the wall where ground levels are regularly monitored. Varying ground level beneath the wall would indicate failure of the sheet piling. RAB reviewed several years of data provided by East Suffolk Council to get an understanding of the expected annual change and also graded the inspection chambers.
The assessment and recommended future management programme we have provided will allow East Suffolk Council to forecast for maintenance and replacements that will improve efficiency, reducing timescales between repairs being identified and works taking place. The provided overall residual life of the asset has given a timescale for its eventual replacement, providing reassurance to the community and the council.
Construction Testing Solutions provided the material testing service by conducting surface tests and scans and extracting concrete cores and dust samples for off-site testing.
RAB deliver a wide range of asset management, public safety and engineering services for both public and private sector organisations. More information is available here on our website, or you can get in touch for an informal discussion on your specific project by email to enquiries@rabconsultants.co.uk or call our head office in Lichfield on 0330 223 6475.
