project: Haslar Bridge Cathodic Protection

client: Raymond Brown Construction Ltd
location: Gosport Docks
duration: 5 months
value: £365,000

scope of works:

Concrete repairs
Reinforcement replacement
Installation of an impressed current cathodic protection system
Bonding and coating of corroded bridge bearings
Application of a protective coating

“CRL were very professional in their approach and with the execution of the works carried out.”

Rob Green
Site Manager
Raymond Brown Construction Ltd

Haslar Bridge is a nine span post-tensioned bridge in the Gosport tidal estuary, in a Site of Special Scientific Interest (SSSI).

CRL carried out major sequenced concrete repairs to the eight number piers (32 columns) in the tidal zone installing replacement steel reinforcement where needed and using a flowable concrete to reinstate. A high standard of repair finish was achieved by using a flexible formwork former strapped to the columns.

The cathodic protection system was installed to protect the steel reinforcement in the piers and cross head beams from further corrosion. The system was divided into 20 anode zones and over 800 discrete mixed metal oxide coated titanium anodes embedded in the original concrete. The power and control system located at one end of the bridge. The electrical systems for the CP system were installed by CRL’s sister company, Equilux.

Other works included bonding the bridge bearings into the CP system negative to avoid stray current corrosion and applying a protective coating to the bearings.

Despite the quantity of repairs increasing by 200% CRL were able to complete the works within the original time frame using additional resources and a flexible work pattern to maximise tidal working time.