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Case Study

Lilley Bottom Bridge

Lilley Bottom Bridge was constructed circa 1972 as part of the Lilley Bypass works. The structure comprises a carriageway and two footpaths over the A505 near Lilley.


Hertfordshire, UK


Hertfordshire City Council


July 2018



Lilley Bottom Bridge - icon problem

The Problem Identified

The structure incorporates a central deck section supported on half joints on cantilevered extensions to the side spans.

The existing expansion joints had deteriorated leading to water ingress and a risk of chloride induced corrosion of the congested steel reinforcement deep within the joint.

Lilley Bottom Bridge - icon solution

The Solution Developed

As the expansion joints were due to be replaced the opportunity was taken to install the ProtectorJoint™ system inside the joint cavity whilst access was available.

The ProtectorJoint™ anodes were pre-connected and installed at 400mm centres. The anode features a galvanic plate on one face and a compressed foam pad on the back which, when released, presses the anode onto the concrete surface and holds it securely as the joint expands and contracts. The anode material will sacrificially corrode in preference to the surrounding steel reinforcement.

The string of anodes was connected to the steel reinforcement via a surface mounted connection box, located at the side of the bridge, where measurements can be taken to monitor system performance.

Lilley Bottom Bridge - icon benefits

The Benefits Provided

The risk of corrosion related deterioration around the expansion joints at Lilley Bottom Bridge has been mitigated.

The simplicity and speed of installation meant that the ProtectorJoint anodes could be installed into two bridge joints during a single night closure

The ProtectorJoint™ system is self-powered thus minimising future maintenance requirements and associated life costs. The ProtectorJoint™ system will provide effective corrosion control for a life of up 20 years.

Lilley Bottom Bridge - PJ installation
Onsite installation of ProtectorJoint™
Lilley Bottom Bridge - PJ installation2
ProtectorJoint™ Solution

Learn more about PROTECTORJOINT™

PROTECTORJOINT™ - ProtectorJoint Banner


Utilises existing joint cavities for powerful long-term protection.

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