FReET-D

Feasible Reliability Engineering Tool for Degradation effects assessment is an optional module of the probabilistic software FReET. FReET-D serves for probabilistic modelling of degradation phenomena in reinforced and pre-stressed concrete structures due to environmental processes. It enables prediction of service life, statistical analysis (statistical parameters of degradation measures), sensitivity analysis (sensitivity of output on different inputs) and reliability analysis (assessment of reliability measures corresponding to target service life and limit state functions).

FReET-D software consists of:

• the full M-version of the FReET software
• the special degradation module

FReET-D covers several important degradation mechanisms:

• carbonation of concrete: 10 models + 3 modifications (progress of carbonation depth over time, time to reinforcement depassivation)
• ingress of chloride ions: 3 models + 3 modifications (depth of chlorination, concentration of chlorides at specified depth, time to reinforcement depassivation)
• corrosion of reinforcement: 3 models (effects on net rebar diameter, depth of pit)
• cracks in concrete due to corrosion: 3 models (time to cracking initiation, corrosion induced crack width in concrete cover)
• stress corrosion cracking: 1 model + 1 modification (stress intensity factor at surface crack tip)
• implementation of additional models is in process.

Generally, durability is one of the decisive structural performance characteristics and is quantified as service life. Relevant assessment processes deal with:

1. the assessment of reliability (or safety) level of the particular limit state;
2. the prediction of service life (for newly designed structures) or assessment of residual service life (for existing structures);
3. the conclusions, decisions and optimization to be carried out for the structure under consideration.

FReET-D can serve for such purposes as a user-friendly tool. For the purposes of the assessment of target (design) service life the user may create different limit conditions relevant to initiation period (reinforcement depassivation) or propagation period (reinforcement corrosion, concrete cracking).

Papers on applications of FReET-D can be found in section Publications.