Bridge Scour Management to CS469 Limited is a small civil and maritime consultancy with over 40 years of international experience.
Please NOTE: My e-mail address; info@praeparatus.com has crashed due to the C-Panel server company going out of business. Use praeparatus52@gmail.com
Note: This web site has now been updated to reflect the new (Jan 2025) rebranded company; “Bridge Scour Management to CS469 Limited from the earlier, “Praeparatus Limited” Company.
The company usually specialises in Project Management and Design Co-ordination. However, in response to the increasing threat from Climate Change and extreme weather events, the new company has developed a highway bridge scour risk assessment package. The scour risk assessment process we provide fully complies with the requirements of the UK D.M.R.B. Standards for Highways, Inspection and Assessment, version 1.0.0 CS469 – “Management of scour and other hydraulic actions at highway structures”. This document came into effect in April 2024 and supersedes BD97/12 – “The Assessment of Scour and other hydraulic actions at Highway Bridges.”
All Highway Authorities have a programme of bridge maintenance and Inspections. For Special Inspections on road over river bridges, underwater examinations are necessary to determine the condition of the river bed at the bridge foundations. This is all well and good, but it does not assess how resilient the bridge structure is to the effects extreme flooding events. Recent flooding events from the major storm Desmond in Cumbria in 2015 and from around the world, show the catastrophic effects of flood water. The resulting storm waters can create bridge scour, foundation undermining and ultimately bridge collapse. This causes a threat to life and property and cuts off communities by destroying our vital infrastructure.
To carry out the CS469 scour risk assessments, Bridge Scour Management to CS469 will issue an individual site inspection proforma for the bridge inspectors to use to gather the site data. In the majority of cases, a topographical survey & an underwater examination is required. The bridge data is then entered into a Level 1 scour risk assessment workbook to determine the Level 1 Scour Risk Rating. If this initial assessment scour risk rating is a score of 10 or less then it is deemed to be a Low Risk structure, and there is no need to progress further. If however, the scour risk rating is over 10 then then it is recommended to undertake a Level 2 assessment, using the Level 2 SRA workbook. The Level 2 SRA work involves the use of the FEH web site to establish the catchment and then uses the WINFAP software to determine the 0.5%AEP or a 1:200 year return period storm flow at the bridge. The hydraulic characteristics of the river and the geometry of the bridge are used to determine the flow velocity and hence the theoretical depth of scour. If the Level 2 SRA gives either a 40 or 60 risk rating then the structure is deemed at medium risk. With a scour risk rating of 80 or 100 then the bridge is deemed to be a high risk structure. Advice is then given on how to improve the resilience of the bridge and how to protect it from extreme weather flooding events.
Don’t let this happen to one of your bridges!
Completed Assessments To Date
This Consultancy has previously completed 155no. Level 1 and 92no. Level 2 BD97/12 bridge scour assessments for Warwickshire C.C. and 11no. Level 1 and 2 scour assessments for Solihull Met. B.C.
In early 2024 we have completed fifteen BD97/12 level 1 & level 2 SRA’s for Inertia Consulting. In light of the Standards for Highways new document, all structures will now be assessed in accordance with the CS469 code.
What We Offer
The bridge scour assessments to CS469 can be arranged for example, by using a Supplier Consultancy contract directly with the Highway Authority. These bridge scour assessments are a very cost-effective method for prioritising the needs of the Local Authority and for planning works to protect the infrastructure.
Bridge Scour Management to CS469 can also offers Project Management and Design Co-ordination services. We can arrange all types of bridge examinations, Special Inspections as underwater examinations with STE07 qualified diving teams and small craft boat surveying.