Structural bridge assessment of the Effensebrug in Breda

As part of its ‘Openbare Ruimte op Orde’ programme (i.e. a programme for maintaining safe and reliable public spaces), the Municipality of Breda is investigating bridges for which no structural calculations are available. The aim is to establish the structural capacity of these assets. Given the damage already identified, the Municipality of Breda selected the Effensebrug as one of the first bridges for investigation under the programme.

Under a framework agreement, Iv is carrying out several of these investigations for the Municipality of Breda. For the structural assessment of the Effensebrug, Iv combined the findings of previous inspections with additional concrete investigations of the existing structure.

Therefore, to properly assess the remaining structural capacity, Iv first had to establish the properties of the existing structure in greater detail. The reinforcement was scanned non-destructively and investigated locally to determine its configuration and bar diameters. In addition, Iv tested concrete cores and material samples to establish aspects including concrete quality, chloride ingress and carbonation.  On Iv’s recommendation, an underwater inspection was carried out to assess the condition of the pile-to-cap connection. This revealed that contact between the pile and pile cap had been lost in some locations.

Using the results of these inspections, Iv was able to carry out the structural assessment and assess the load-bearing capacity of the frame and supporting structure. For the frame, this involved refining the calculation model, redistributing forces and taking operational restrictions into account.

The structural assessment provided the Municipality of Breda with the concrete information needed to take immediate action. Iv recommended a load restriction and road narrowing, and the municipality immediately implemented both measures.

In addition to these immediate measures, the assessment at rejection level showed that further measures would be required within one year. Given the technical condition of the Effensebrug, Iv recommended replacing the bridge in the short term. Following this recommendation, the Municipality of Breda has scheduled the bridge for replacement.

Until the bridge is replaced, the operational restrictions that have been put in place will help control its use. In this way, Iv’s investigation provides the technical basis for both the short-term measures and the future replacement of the Effensebrug.