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Cathodic protection design

Well designed cathodic protection reduces safety risk and considerably increases the lifetime of underwater harbour structures.

Whether you are planning to build a new harbour or maintain existing steelworks, our team of engineers collaborate to ensure full corrosion control throughout the entire life of the structure.

Sheet pile walls and tubular piles can be protected by either ICCP or sacrificial anodes, optimised for each particular project.

Harbour potential measurement survey
Harbour potential measurement survey

Design codes

Cathodic protection of sheet piling and tubular support piles structures is designed based on established codes, but also a good share of experience. If not otherwise specified, design work by Cathwell will be conducted in adherence with the following codes:

NS-EN ISO 13174:2012: Defines the means to be used to ensure that adequate cathodic protection is applied to the immersed and driven/buried metallic external surfaces of steel port, harbour, coastal and flood defence installations.

DNV-RP-B401: Recommended practice for design, manufacture and installation of sacrificial anodes, primarily intended for CP of permanently installed offshore structures associated with the production of oil and gas.


Cathodic protection by impressed current cathodic protection is designed either by mounting ICCP anodes directly to the steelworks, or alternatively arranging anode sleds at the sea bottom underneath the jetty or beside the sheet pile wall. Both have advantages and disadvantages, and considerations should be taken to find the optimum arrangement for each project.

A proper monitoring system with reference electrodes will ensure full control and correct level of protection. The ICCP system is powered by an automatic regulated ICCP control panel.

Impressed current anode for harbour structures
Impressed current anode for harbour structures

Sacrificial anodes

A maintenance free system designed to meet applied specification requirements and requested design lifetime. The sacrificial anodes can be customised to fit any kind of harbour structure. The detail design includes detail drawings and procedures for installation. You may also read about sacrificial anodes for harbours.

Sacrificial anodes for sheet pile wall
Sacrificial anodes for sheet pile wall

Design basis

This section applies both for new structures and retrofitting, and are also relevant in verifying existing designs.

By providing the below listed information (for the system in question), we would be able to carry out a proper design. If not all details are available, we could start with what you have, and adjust as we go along.

  1. Geographical location.
  2. GA drawing or sketch with dimensional information.
  3. Sheet pile specification/type (if available).
  4. Water depth (MWL) along the structure(s).
  5. Sediment depth along the structure(s).
  6. Requested design lifetime of protection (typically 20, 25 or 30 years).
  7. System preference, if any (protection by ICCP or sacrificial anodes).

The inquiry should state whether it concerns a new construction or an existing structure.

Allowance for metal loss

It is generally most rational that sheet piles are designed for being cathodically protected on the sea side, but dimensioned with allowance for metal loss on the shore side.

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