Operability and transitability verifications of bridges and viaducts

Operability and passability inspections of existing bridges and viaducts are crucial processes to ensure the safety and functionality of road and rail infrastructure, as well as its durability over time. Inspections are carried out periodically to survey, identify and keep monitored the evolution of complex wear and tear and degradation phenomena in order to ensure the safe use of the work and to plan over time maintenance and improvement works on the infrastructure causing limited inconvenience to the traffic of people and goods.

These activities are governed by the Guidelines drawn up by the Ministry of Infrastructure and Sustainable Mobility – with technical advice from the Superior Council of Public Works (CSLP) – and are conducted through a multilevel approach, at the end of which it is possible to determine whether the bridge or viaduct can be used with load and/or geometric limitations or whether it already complies with the provisions of the Technical Construction Standards defined by the Ministerial Decree of 17 January 2018.

The approach used consists of several levels of risk analysis, starting with the census of bridges and viaducts (Level 0) and visual inspection of the area (Level 1), and continuing with the determination of the infrastructure’s attention class (Level 2) up to the bearing capacity verifications (Levels 3 and 4) comprising all on-site diagnostic activities, static load tests, dynamic surveys and instrumental monitoring scheduled over time, with the aim of assisting the commissioned entity in the management and planning of maintenance interventions.