FReET-D

Feasible Reliability Engineering Tool for Degradation effects assessment in reinforced and pre-stressed concrete structures. It is an optional module of the probabilistic software FReET. FReET-D serves for probabilistic modelling of degradation phenomena due to environmental processes and can serve for design or performance-based specification.

FReET-D software enables:

• prediction of service life
• statistical analysis (statistical parameters of degradation measures)
• sensitivity analysis (sensitivity of output on different inputs)
• reliability analysis (assessment of reliability measures corresponding to target service life and different limit state functions)

FReET-D software consists of:

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

FReET-D supports new trends according to:

• fib Model Code 2010
• ISO 13823 (2008) General Principles on the Design of Structures for Durability

Degradation mechanism	Model notation	Output	Released
Carbonation	Carb1a Carb1b	Carbonation depth at time t; time to depassivation	2006 2006, amended 2010
	Carb2a Carb2b		2006 2006, amended 2010
	Carb3		2006
	Carb4a Carb4b		2006 2006, amended 2010
	Carb5a Carb5b		2006 2006
	Carb6		2006
	Carb7		2006
	Carb8a		2006
	Carb9		2006
Carbonation + mechanical load	Carb8b	Carbonation depth at time t; time to depassivation	2015
Choride ingress	Chlor1a Chlor1b	Depth of chlorination at time t; time to depassivation	2006 2006
	Chlor2a Chlor2b	Depth of chlorination at time t	2006 2006
	Chlor3a Chlor3b		2006 2006
	Chlor4		2008
Chloride ingress + mechanical load	Chlor5a Chlor5b Chlor5c	Concentration of chlorides at depth x and time t	2015
Corrosion of reinforcement	Corr1	Net rebar diameter at time t	2006
	Corr2	Pit depth at time t	2006
	Corr3	Net cross sectional area of rebar at time t	2006
	Corr4	Time to cracking due to corrosion	2006
	Corr5	Crack width due to corrosion at time t	2008
	Corr6	Time to cracking due to corrosion	2008
	Corr7	Strength and ductility of corroded steel	2012
	Scc1a Scc1b	Stress intensity factor at the pit tip at time t	2006 2006
Frost attack	Fros1	Actual degree of saturation	2008
	Fros2	Internal damage (relative dynamic modulus of elasticity)
	Fros3
	Scal1	Surface scalling
Sulphate attack on concrete in sewer collection systems	Sulf1a	Rate of concrete corrosion	2012
	Sulf1b
	Sulf1c
Acid attack on concrete	Acid1a	Depth of concrete corrosion for user defined concentration of the acid	2012
	Acid1b	Depth of concrete corrosion for user defined pH of mineral acid solution
	Acid1c	Depth of concrete corrosion for buffering media consideration

Detailed theoretical manuals including description of applied models as well as user's guide with tutorial and illustrative examples are available.

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 degradation processes in the course of time
2. the prediction of service life (for newly designed structures) or assessment of residual service life (for existing structures)
3. the assessment of reliability (safety) level for the particular limit state
4. based on (i) to (iii) the conclusions, decisions and optimization can 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 e.g. the initiation period (reinforcement depassivation) or propagation period (reinforcement corrosion, concrete cracking) and exposition conditions.

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

Demo version of FReET-D is available in section Download.