The map below displays, for all countries for which data is available, the inspection intervals in months.

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Inspection intervals in months

The change in the state of preservation compared to the last inspection event (inspection/testing) is determined, documented and assessed. This is usually done by visual inspection, unless components are to be inspected more closely in accordance with special inspection instructions. A competent engineer, appropriately trained (e.g. internal training of the owner, education and training) or experienced technical personnel (e.g. bridge foreman) is to be entrusted with the execution.

Maintenance strategy and limits

Inspection procedures can be assigned to the preventive maintenance strategy since there is the intention to a continuous observation of the condition class development. However, if the structure is already in a certain poor condition class, some countries prefer to apply a corrective maintenance strategy.

Time intervals

Inspections are mostly carried out at intervals of two to four years or, if the condition of the object requires it, at shorter intervals. After extraordinary events such as floods, earthquakes, avalanches or debris flows, landslides, accidents (fire or impact of vehicles), the affected structures are specifically checked for their possible impact. The inspection intervals are more or less closely related to the routine monitoring considerations and the associated time intervals are determined according to the information from the (COST TU1406) surveys and the D1.3 Annex 2 information based on the occurring damages, climatic conditions, traffic load and winter maintenance, the available budget and manpower.


Based on the result of the inspection, the following is in general documented:

  • Condition of the object compared with the last finding,
  • Usability of the traffic route in the previous scope depending on the condition of the object,
  • Newly detected defects/damage,
  • Immediate measures based on the detected defects/damage,
  • Arrangement of an inspection, if defects/damage cannot be assessed in the course of the inspection,
  • Special instructions for the next inspection/testing,
  • Year of next inspection.