Client
Raymond Brown Construction Ltd
Value
£365,000
Sectors & Services
Highway Structures Marine Structures Concrete Repair Coatings Corrosion Control Cleaning & Preparation Projects Projects
Haslar Bridge is a nine-span, post-tensioned concrete structure crossing the Gosport tidal estuary and located within a designated Site of Special Scientific Interest. The bridge is a vital transport link on the south coast and its substructure is continuously exposed to a highly aggressive marine environment.
Detailed inspections identified significant deterioration to the reinforced concrete piers and crosshead beams, particularly within the tidal zone, with corrosion-related damage evident to the embedded steel reinforcement. To safeguard the structural integrity of the bridge and extend its operational life, a programme of major concrete repairs and cathodic protection works was commissioned, requiring careful sequencing and environmental sensitivity.
Services undertaken
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Sequenced reinforced concrete repairs to bridge piers and columns
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Installation of replacement steel reinforcement
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Flowable concrete reinstatement to tidal zone elements
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Flexible formwork systems to achieve high-quality repair finishes
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Installation of impressed current cathodic protection system
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Embedding of mixed metal oxide titanium anodes
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Zoning and commissioning of cathodic protection control systems
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Bonding of bridge bearings into cathodic protection system
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Application of protective coatings to bridge bearings
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Programme acceleration using additional resources and flexible tidal working patterns
CRL was appointed to undertake major, sequenced concrete repairs to eight piers comprising a total of 32 reinforced concrete columns located within the tidal zone. The marine environment and fluctuating water levels required a carefully planned methodology to maximise productive working time while maintaining quality and safety. Defective concrete was broken out in a controlled manner, with replacement steel reinforcement installed where required to reinstate structural capacity and continuity.
Repairs were completed using a high-quality flowable concrete, selected to ensure full encapsulation of reinforcement and consistent compaction within complex column geometries. To achieve a uniform and durable finish, CRL utilised a flexible formwork former strapped directly to the columns. This approach enabled excellent surface quality and dimensional control, while accommodating minor variations in column profile. The result was a high standard of finish appropriate for a prominent and environmentally sensitive structure.
In parallel with the concrete repairs, CRL installed a comprehensive cathodic protection system designed to arrest ongoing corrosion of the reinforcement within the piers and crosshead beams. The system was divided into 20 discrete anode zones and incorporated over 800 mixed metal oxide coated titanium anodes embedded within the original concrete. Power supply and control equipment was located at one end of the bridge to allow effective monitoring and management of the system. Electrical installation works associated with the cathodic protection were delivered by CRL’s sister company, Equilux, ensuring seamless integration and single-point responsibility.
Additional scope included bonding the bridge bearings into the cathodic protection system negative to mitigate the risk of stray current corrosion, together with the application of a protective coating to the bearings. Despite the repair quantities increasing by approximately 200 percent during the works, CRL successfully maintained programme delivery by deploying additional resources and adopting a flexible working pattern to maximise tidal access. This demonstrated CRL’s capability in delivering complex structural repairs UK within challenging marine and environmental constraints.
“CRL were very professional in their approach and with the execution of the works carried out.”
Rob Green | Site Manager | Raymond Brown Construction Ltd
The repair and protection strategy for Haslar Bridge was designed to deliver long-term durability and resilience within an aggressive tidal environment. High-quality surface preparation, controlled concrete breakout and the use of flowable repair concrete ensured effective reinstatement and long-term bond performance. The installation of a zoned cathodic protection system provides ongoing corrosion control to the embedded reinforcement, significantly reducing the risk of future deterioration.
By integrating bearings into the cathodic protection system and applying protective coatings, potential secondary corrosion mechanisms were also addressed. This holistic approach supports effective asset management by reducing future maintenance demands and extending the service life of the bridge. CRL’s ability to combine specialist concrete repairs with advanced corrosion prevention measures has preserved a vital south coast structure while ensuring long-term performance and reliability.
