Impressed Current Cathodic Protection: Bridge 111

Reinforced concrete motorway bridge, Herstal, Wallonia, Belgium

BlueSpine is supporting the rehabilitation of a 1960s reinforced concrete motorway bridge affected by advanced corrosion of its cantilever beaks. Discover how a mixed system of drilled MMO titanium anodes and a carbon-based electroconductive coating, sized with the help of a full-scale 3D digital twin, made it possible to design an effective impressed current cathodic protection system on this complex structure.

The structure

Bridge 111 is a reinforced concrete motorway bridge dating from the early 1960s, located in the municipality of Herstal in Wallonia, Belgium. It spans several railway lines as well as two surfaced roads, carrying the A13 motorway that links Antwerp to Liège.

The brief

Recommendation and sizing of the impressed current cathodic protection system.

Project stakeholders

Owner: Service public de Wallonie (SPW)

Our work

BlueSpine was commissioned to carry out the sizing study for an impressed current cathodic protection (ICCP) system on the cantilever beaks and beams of Bridge 111.

The corrosion diagnosis

The diagnosis carried out by the SPW had revealed advanced corrosion on the cantilever beaks, in the degraded expansion joint zones, initiated by chlorides. In addition, significant carbonation depths were affecting the stirrups of the longitudinal beams and the cross-beams of the central span.

A full-scale 3D digital twin

Given the geometric complexity of the structure, a full-scale 3D digital twin was built to simulate the distribution of the protection current and to size the installation precisely.

A mixed anode system

The recommended system combines two types of anodes:

• Drilled MMO titanium anodes
• Carbon-based electroconductive coating

The simulations confirmed that this mixed system places all the reinforcement at least in cathodic prevention, and the vast majority in active cathodic protection, in accordance with the criteria of standard EN ISO 12696.