Power Station Sea Wall Repair

The Challenge

We were asked by the Investment Delivery Team of an existing power station client to carry out concrete repair work to a 40-metre-long section of sea wall which included crane support and cantilever beams. The steel rebar had rusted, and concrete spalling was found to most of the beams and wall.

The challenge was access to the area to be repaired, which was in direct contact with the sea and no access possible from the station itself. 6-metre-high rising tides were another challenge to overcome.

The Approach

The first stage was to think innovatively about how to access the repair area. We worked with North East Safety Boats, who built a bespoke barge for the project using NATO pontoons. The barge was delivered to the site location via the Tees estuary in 3 sections, which were then rigged together and supervised by qualified personnel throughout the entire project, raising and lowering the barge as required in response to sea levels through means of a winch. The barge was fully calculated for stability and mooring analysis carried out to ensure safety and confidence of those working on the project.

These steps allowed the CSC team to work safely on the concrete repair, in the following stages:

Hammer test and cut to identify repair areas
Hydro-demolition to take out the defective concrete
Handover to engineering team to carry out full inspection of the rebar to be replaced
Cathodic protection using sacrificial anodes installed by our corrosion technician before being signed off by the engineering team
Area then repaired back to profile through concrete dry spraying process.
The Full repaired area including sections not repaired were overcoated to protect from future chloride ingress issues.

The work entailed a 12-man team, consisting of 6 concrete repair and corrosion specialists from the CSC team, with support from North East Safety Boats and Buxton Water over a project completion period of 14 weeks.