Client
Octavius Infrastructure Limited
Value
£105k
Sectors & Services
Highway Structures Concrete Repair Coatings Corrosion Control Cleaning & Preparation
The M25 Ship Lane Overbridge, constructed in 1977, carries the M25 motorway over Ship Lane and features twin simply supported solid reinforced concrete slabs, each 600 mm thick. Its reinforced concrete cantilevered abutments rest on spread foundations at either deck end.
In early 2021, a detailed investigation by WSP identified leakage through the central deck joint, alongside extensive spalling and delamination on the soffit and abutments. The defects, primarily caused by water ingress, posed a risk to the bridge's structural integrity and required comprehensive remedial works.
CRL was commissioned via Octavius Infrastructure Limited to replace the deck joints, install a complete waterproofing system, and repair all affected concrete areas in compliance with Highways specifications, ensuring long-term durability and safety for one of the region’s critical transport links.
Services undertaken
- Hydrodemolition of defective concrete on soffit and abutments
- Installation of CPT Patch Gard galvanic anodes
- Reinstatement of concrete using Weber DS & RS spray
- Replacement of longitudinal and expansion joints
- Installation of full deck waterproofing system
- Phased soffit repair sequencing
- Formwork to maintain ribbed abutment features
- Test panel cores for compressive strength assessment
- Traffic management and 24/7 road closure supervision
- Use of scissor lifts for safe access to works face
CRL’s remedial works were carefully planned to minimise disruption while addressing all structural deficiencies. Following the closure of the underpass, works were delivered over eleven 12-hour shifts. Initial activities included hydro demolition of defective concrete around the soffit expansion joint and abutment walls, removing all spalled, delaminated, and cracked material. CPT Patch Gard galvanic anodes were installed within the prepared patches to provide corrosion protection to the embedded reinforcement, before reinstatement with Weber DS & RS spray-applied concrete.
The soffit repairs were executed in a phased sequence (1, 3, and 5 followed by 2, 4, and 6) as per the designer's requirements, while abutment repairs were carried out concurrently. Maintaining the ribbed profile of the abutment walls was critical; straight-edge timber formwork was used to replicate the original architectural features precisely. Test panel cores were extracted and tested for compressive strength to confirm the performance of the sprayed concrete system. Access to the works face was facilitated by scissor lifts operated by CRL’s IPAF-trained personnel under a 24/7 traffic management system, ensuring safe and efficient delivery. The works also included the replacement of longitudinal and expansion joints and the installation of a full deck waterproofing system to prevent future water ingress and associated concrete deterioration.
"The tight programme and having to work 24/7 was a tough ask, but I am glad to say out Team were up to the task and performed well."
Kevin Hodgson | Senior Contracts Manager | CRL
CRL’s intervention not only restored the structural integrity of the M25 Ship Lane Overbridge but also significantly enhanced its durability and operational resilience. Installation of galvanic anodes and a comprehensive deck waterproofing system provides long-term corrosion protection, reducing maintenance frequency and safeguarding the superstructure against further water-related damage.
The careful reinstatement of architectural features, combined with phased, safely managed works, ensured minimal disruption to traffic while delivering a technically robust solution.
This proactive approach supports asset management objectives, extends service life, and demonstrates CRL’s expertise in structural repairs in the UK, combining high-quality workmanship, detailed planning, and innovative techniques to protect a vital transport asset for decades to come.
