An inspection cofferdam is typically 2 meters wide and can be built up according the requested inspection depth. This cofferdam fits on the back of a truck and can be transported as such. An inspection of a quay wall in detail will be executed with reference setups (decided in a joint decision between the client and Acotec) where the cofferdam will be placed. This will generally be on the locations where damage can be seen such as holing or even a subsidence of the quay.
An inspection can be performed by Acotec, by the client itself or by a third party which is mostly an engineering company.
When Acotec performs the inspection, a typical setup includes:
- visual inspection,
- cleaning of the biofilm and vegetation,
- remaining steel thickness measurements on every inpan, flange and outpan for every meter below the waterline,
- potential measurements,
- coupon analysis to determine corrosion from the backside,
- test to determine bacterial corrosion,
- remaining film thickness of possible old coatings,
- inspection of former corrosion protection tools present,
- possible repairs when requested by the client.
An inspection in the dry gives a number of advantages:
- The infrastructure is clearly visible
- You can wash away the biofilm and vegetation and collect any loose material
- You don’t depend on the diver’s interpretation, but you can inspect yourself
- By taking away the front pressure on the waterside, any leakage and holing will become visible, even the smallest
- Any holing found, can be repaired immediately, during the inspection
A detailed cofferdam inspection is often required prior to a full renovation project or refurbishment of a jetty or bulkhead structure. The results of the inspection can be a direct input to determine the size and budget for the project.