Page 362 - 360.revista de Alta Velocidad - Nº 5

Campos Zaldiernas, Javier. Díaz García, Sarai. Galán Alguacil, Álvaro. González Pérez, Javier.

Identification of the influence level of each risk factor is crucial in order to determine the
optimal remedial works to be undertaken in each asset.
Failure consequences

The main purpose of the consequence analysis is to identify the effects of the hazards on the
element at risk. The consequences of the culvert failure can be described as the socioeconomic
impact produced by subsequent traffic disruption. Those consequences are divided into two
main categories:
• Consequence for risk to life: qualitative analysis of the risk to life assessed as the combi-
nation of the specific vulnerability (track speed limit, height of fill, security level) and the
temporal probability (linked with the average railway traffic intensity).

• Consequence for risk to property and socioeconomic impacts: consequence with respect to
property damage and other consequential effects (traffic disruption) of the failure are to
be assessed by a quantitative analysis of the economic repercussion caused by each specific
failure mechanism. The type of damages and adverse effects are different depending on the
nature of the mechanism. In general terms, these consequences can be divided into two
main categories:
- Direct economic costs: there are some consequences that directly affect the railway
administration such as rehabilitation and repair costs.
- Indirect economic costs: on the other hand, some impacts are not directly assumed by
the competent administration but they affect society as a whole. These costs include:

• Traffic disruption costs: linked with the increase in travel times derived from circula-
tion by alternatives routes of the rail network (Perrin and Jhaveri, 2003).
• Compensation costs derived from landslide impact on near properties due to em-
bankment slope instability: in this case the economic impact depend on many factors
such as: height of fill, type of property affected, distance from the element to the
failure influence area and general nature of adjacent development.
• Compensation costs derived from flooding upstream the culvert: in many cases the
flooding is caused by the insufficient hydraulic capacity of the culvert so the compen-
sation must be held by an insurance company or the proper administration. Upstream
nearest crops and constructions may be affected as long as the flood remains.

• Traffic disruption costs in upstream adjacent transport infrastructures (other rai-
lways or roadways) caused by floods.

Global socioeconomic impact will be assessed for each failure mechanism considering that the
consequences of failure may depend on the nature of the failure itself. Where there are mul-
tiple consequences, the total should be considered, as it may increase the consequence class
above that derived from the individual effects. Note that the consequence classes used for
loss of life (combined vulnerability and temporal probability) are not considered equivalent in
economic terms to those for the damage to property and consequential effects, reflecting the
lower tolerance which exist in society for loss of life compared to pure economic losses.

Culvert failure risk analysis
Once the annual probability of failure linked to each of the ten mechanisms studied is obtained
and knowing the level of economic and social impact associated with each culvert, it is possible
to determine the preliminary risk level of the asset. The risk level associated with a particular
culvert is the direct result of the integration of the annual failure probabilities and the eventual

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