6. Notion of limit states and service life

In general, when we talk about the service life of a structure, we consider the period during which the structure provides its required level of service under normal loading and with routine maintenance (we're only considering structural elements here).

We have seen that corrosion degradation of concrete structures can be described in two stages: the incubation period and the propagation period. Generally speaking, the service life of structures is defined as being equal to the incubation period. This is a safe (conservative) approach, because when the propagation phase starts with the first corroded sites, the structure still has a significant safety margin.

• Limit states

  This service life is therefore to be considered as the "nominal" end-of-life of the structure, bearing in mind that it...