Service life prediction of concrete sructures (Methodologies for Service…
Service life prediction of concrete sructures
LCC (life-cycle cost), a methodology that accounts for the total cost of building elements during their life cycle
studies apply an average service life value for a given building element, without considering the specific conditions that it will be subjected to, thus introducing additional uncertainty
the service life of any given element may vary significantly from building to building, since each building is a prototype that responds to unrepeatable conditions.
(i) Physical service life
Degradation agents (whether physical, chemical or mechanical) and the natural ageing process. design and construction errors, or the application of inadequate materials.
(ii) Functional service life
The functional service life is directly related with the
expectations and demands of the users.
(iii) Economic service life
Economic service life can be deﬁned as the time elapsing since the construction is placed into use until the instant that it is replaced by a more proﬁtable solution.
Methodologies for Service Life Prediction
Easy to understand and apply;
can be easily implemented, and maintain their operability even when all the variables related to the modelled phenomena are unknown.
Unable to capture the random nature of the degradation phenomena.
Does not provide any information regarding the degradation process or related to the probability of transition from one degradation condition to another
Empirical methods have been developed to evaluate the durability under real conditions of service
Multiple non-linear regression analysis
Multiple linear regression analysis:
Simple regression analysis (linear and non-linear)
Three main drawbacks
complexity of the mathematical expressions
large amount of data required necessary to validate the model, which should preferably be collected over a long period of time.
the great dependence of the fieldwork.
Most literature focus one type of material only—usually reinforced concrete—subjected only to a degradation agent (usually chloride attack)
Markovian transition matrix
Trend plots method
MEDIC method : evaluating the residual service life of the buildings
The European project Energy Performance Indoor Environment Quality Retrofit (EPIQR)
Failure Modes and Effects Analysis (FMEA)
Performance Limits method: to evaluate the durability of
building components by simulating their performance over time.
Engineering models possess an acceptable level of
complexity and are implemented using probabilistic data, leading to simple deterministic equations
Fuzzy logic systems.
Artificial neural networks