Page 361 - 360.revista de Alta Velocidad - Nº 5

A railway culvert maintenance management approach based on risk assessment techniques

• Triggering event: on the other hand, once the precedent event has taken place, the
triggering event reveals the likelihood of the infrastructure to be affected by the failure
mechanisms. In this case the annual probability of failure may depend on the culvert
component geometry and configuration. Depending on parameters such as the height of
fill, the soil type and embankment configuration, the global failure probability may vary
according to the ability of the current configuration to potentiate or mitigate the adverse
effects of the triggering events.
A series of specific studies have to be carried out in order to assess the probability of certain
events previously mentioned. Some of which are:
• Hydrologic characterization of the drainage basin: a complete preliminary characterization
of the watershed must be undertaken. Hydrologic semi distributed models are applied in
order to proceed to the upstream peak flows calculation.
• Hydraulic characterization of the culvert: according to the culvert current configuration,
geometry and waterway characteristics, the hydraulic performance of the culvert in the
peak flow situations can be obtained.

• Embankment slope instability caused by afflux preliminary studies: considering the hydraulic
performance of the culvert previously obtained.

• Embankment slope instability caused by undermining at inlet or outlet preliminary
assessment based on experimental studies (Galan et al., 2016).

The integration of these specific studies on the global assessment of the failure probability
of each failure mechanism is crucial to identify pathologies linked to potential deficiencies
of the hydraulic capacity of the culvert. Additionally, each failure mechanism can be easily
decomposed into a series of risk factors, defined as the main pathologies that can lead to the
culvert failure. According to its nature, the risk factors are divided into five main categories:

• Partial or total blockage of the culvert barrel.
• Structural deterioration of the culvert barrel.
• Structural deterioration of the culvert headwall or/and wingwalls.
• Evidences of substantial erosion at the culvert outlet or inlet (undermining).
• Deficiencies found in the hydraulic capacity of the culvert.

Figure 2. Risk factors examples: structural deterioration of the culvert barrel, partial blockage of the culvert barrel, evidences
of substantial erosion at the culvert outlet.

International Congress on High-speed Rail: Technologies and Long Term Impacts - Ciudad Real (Spain) - 25th anniversary Madrid-Sevilla corridor 359