SIST-TS CEN/TS 17440:2020

SLOVENSKI STANDARD
01-oktober-2020
Ocenjevanje in obnova obstoječih stavb
Assessment and retrofitting of existing structures
Bewertung und Ertüchtigung von bestehenden Tragwerken
Evaluation et rénovation des structures existantes
Ta slovenski standard je istoveten z: CEN/TS 17440:2020
ICS:
91.010.30 Tehnični vidiki Technical aspects
91.040.01 Stavbe na splošno Buildings in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TS 17440
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
July 2020
TECHNISCHE SPEZIFIKATION
ICS 91.010.30
English Version
Assessment and retrofitting of existing structures
Évaluation et rénovation des structures existantes Bewertung und Ertüchtigung von bestehenden
Tragwerken
This Technical Specification (CEN/TS) was approved by CEN on 3 May 2020 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 17440:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
1.1 Scope of CEN/TS 17440 . 7
1.2 Assumptions . 7
2 Normative references . 7
3 Terms, definitions and symbols . 8
3.1 Terms and definitions . 8
3.2 Symbols . 11
4 Principles of assessment . 13
4.1 Reliability management . 13
4.2 Methods of assessment . 13
4.3 Assessment situations . 13
4.4 Using available information . 14
4.5 Updating available information. 14
4.6 Structures with new elements and retained elements . 14
4.7 Assessment of heritage structures . 14
5 Assessment process . 15
5.1 General. 15
5.2 Initiating the assessment . 15
5.3 Agreeing the assessment scope and objectives . 15
5.4 Developing the assessment approach . 17
5.5 Establishing the structural condition . 17
5.6 Undertaking the assessment . 19
5.7 Reporting the assessment findings . 20
6 Assessment by calculation . 20
6.1 General. 20
6.2 Assessment of action effects . 20
6.3 Assessment of resistances . 21
6.4 Verifications . 21
7 Basic variables and updating . 22
7.1 General. 22
7.2 Geometrical data . 23
7.3 Actions and environmental influences . 23
7.4 Material and product properties . 26
8 Structural modelling, updating and analysis . 28
8.1 Structural layout and boundary conditions . 28
8.2 Structural analysis principles . 28
8.3 Selection of structural analysis methodology . 28
8.4 Testing and monitoring . 29
9 Verifications . 30
9.1 General. 30
9.2 Verification methods . 30
9.3 Partial factor method . 30
9.4 Assessment value method . 32
9.5 Probabilistic method . 33
9.6 Risk assessment method . 33
10 Assessment based on past performance . 34
11 Interventions . 35
11.1 Developing proposals for interventions based on the assessment results . 35
11.2 Immediate interventions . 36
Annex A (informative) Flowchart of assessment processes and interventions . 37
A.1 Use of this informative Annex . 37
A.2 Scope and field of application . 37
Annex B (informative) Updating procedures . 39
B.1 Use of this informative annex. 39
B.2 Scope and field of application . 39
B.3 Updating the basic variables . 39
B.4 Updating the failure probabilities . 42
Annex C (informative) Target reliability and partial factors . 43
C.1 Use of this Informative Annex . 43
C.2 Scope and field of application . 43
C.3 Target reliability . 43
C.4 Partial factors . 44
Annex D (informative) Assessment of heritage structures . 47
D.1 Use of this Informative Annex . 47
D.2 Scope and field of application . 47
D.3 Principles of assessment . 47
D.4 Assessment process . 47
D.5 Assessment based on past performance . 48
D.6 Structural modelling and analysis . 48
D.7 Verification . 49
D.8 Interventions . 49
Bibliography . 50

European foreword
This document (CEN/TS 17440:2020) has been prepared by Technical Committee CEN/TC 250
“Structural Eurocodes”, the secretariat of which is held by BSI. CEN/TC 250 is responsible for all
Structural Eurocodes and has been assigned responsibility for structural and geotechnical design matters
by CEN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under Mandate M/515 issued to CEN by the European Commission
and the European Free Trade Association.
This document has been drafted to be used in conjunction with relevant execution, material, product and
test standards, and to identify requirements for execution, materials, products and testing that are relied
upon by this document.
This document recognizes the responsibility of each Member State and has safeguarded their right to
determine values related to regulatory safety matters at national level through the use of National
Annexes.
The presentation, in Notes to clauses, of national choice in this Technical Specification, does not
everywhere accord with the guidance established by CEN/TC 250 for use in the Eurocode ENs. The
presentation of National choice will be in accordance with the TC’s guidance in formal ENs.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Introduction
General
The Eurocodes comprise rules that are primarily intended for the design of new structures, although the
principles of EN 1990 can also be applied for existing structures, with additional or amended provisions.
CEN/TS 17440 is intended to supply those additional or amended provisions that can enable EN 1990 to
be applied to the structural assessment of existing structures.
Extending the life of existing structural assets is a key challenge for structure owners worldwide.
Investment in accurately assessing the resistance of structures can deliver substantial environmental,
economic and socio-political benefits. In order to fully realize these benefits, it is often necessary in
assessment to go beyond the simple, conservative methods typically used for design, so that reliability of
structures can be more accurately assessed.
In the design of new structures, it is generally necessary to use conservative values for basic variables,
and it is typical to use conservative models for structural analysis. However, when assessing an existing
structure, there is an opportunity to obtain updated data regarding the structure, including its geometry,
its material properties, the actions and environmental influences, and measures relating to its structural
behaviour. There can be significant benefits to be gained from using updated data in the assessment, and
by considering alternative structural analysis models that represent more accurately the limit states
being assessed. CEN/TS 17440 includes provisions related to using updated data and updated structural
models in assessment.
Older structures were often designed and constructed in a way that would not conform with modern
standards for structural design, material products or execution. They can often exhibit deterioration or
damage. A particular challenge in assessment is therefore how to accurately assess structures taking
account of the actual detailing arrangements, material properties, execution tolerances, and the
structural condition. CEN/TS 17440 includes principles for the assessment of structural resistance.
Often, an older structure could need to be modified, extended, repurposed, strengthened or retrofitted in
a way that reuses retained structural elements in combination with new structural elements. In such
schemes, there will be a need to assess the retained elements of the structure, which might not conform
to all the requirements for new design. CEN/TS 17440 includes provisions for the assessment of retained
elements, as well as for the assessment of complete structures.
This document is based on the recommendation of JRC Science and Policy Report on assessment and
retrofitting of existing structures. Upon the agreement of CEN/TC 250, this document can be converted
into a new Eurocode Part.
Verbal forms used in this Technical Specification
The verb “shall” expresses a requirement strictly to be followed and from which no deviation is permitted
in order to comply with the Eurocodes.
The verb “should” expresses a highly recommended choice or course of action. Subject to national
regulation and/or any relevant contractual provisions, alternative approaches could be used/adopted
where technically justified.
The verb “may” expresses a course of action permissible within the limits of the Eurocodes.
The verb “can” expresses possibility and capability; it is used for statements of fact and clarification of
concepts.
National annex for CEN/TS 17440
This document gives values within notes indicating where national choices can be made. Therefore, a
national document implementing CEN/TS 17440 can have a National Annex containing all Nationally
Determined Parameters to be used for the assessment of buildings and civil engineering works in the
relevant country.
National choice is possible in CEN/TS 17440 through the following clauses:
4.1(1), 4.1(3), 4.4(2), 4.6(3), 5.3(1), 5.3(2), 5.3.(3), 6.1(2), 6.3(2), 7.1(5), 7.3.1(4), 7.3.8(1), 7.3.9(1),
7.3.9(2), 7.4.1.4(1), 9.2(1), 9.3(2), 9.3(3), 9.4(4), 9.4(5), 9.5(2), 10(1), D.3.1(1).
National choice is possible in CEN/TS 17440 on the application of the following informative annexes:
• Annex A,
• Annex B,
• Annex C,
• Annex D.
1 Scope
1.1 Scope of CEN/TS 17440
(1)This document provides additional or amended provisions to EN 1990 to cover the assessment of
existing structures (see EN 1990:2002, 1.1(4)), and the retained parts of existing structures that are being
modified, extended, strengthened or retrofitted.
NOTE 1 The assessment of an existing structure is, in many aspects, different from the design of a new structure,
see Introduction.
NOTE 2 There can be some aspects of EN 1990 that are required for design but are not applicable for assessment.
The definition of those aspects of EN 1990 that are not applicable can be included in the definition of the assessment
objectives and the approach to the assessment, see Clause 5.
NOTE 3 This document is based on the general requirements and principles of structural reliability provided in
Eurocodes EN 1990 and EN 1991.
(2) This document covers general principles regarding actions for assessment complementing EN 1991.
NOTE Supplementary provisions for seismic actions due to earthquake are provided in EN 1998.
(3) This document includes general principles for the assessment of the structural resistance of existing
structures.
NOTE The specific models used to assess resistance are not provided in this document and will depend on the
materials and structure types.
(4) This document does not provide specific rules for initiation of assessment.
(5) This document does not provide specific rules on how to undertake interventions that can be carried
out as a result of an assessment.
(6) This document does not cover the design of new elements that will be integrated into an existing
structure.
NOTE For the design of new elements, see EN 1990.
1.2 Assumptions
(1) The general assumptions of CEN/TS 17440 are:
• the assessment of the structure is made by appropriately qualified and experienced personnel;
• adequate supervision and quality control is provided during the assessment process;
• the structure will be used in accordance with the assessment assumptions;
• the structure will be maintained in accordance with the assessment assumptions.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 1990:2002, Eurocode —Basis of structural design
EN 1991, Eurocode 1: Actions on structures
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1990 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
assessment
set of activities performed in order to verify the reliability of an existing structure
[SOURCE: ISO 13822:2010, 3.1 — modified]
3.1.2
assessment situation
physical conditions that could occur during a certain time period for which the assessment is intended to
demonstrate, with sufficient reliability, that relevant limit states are not exceeded
3.1.3
assessment value
value of a variable applied in the analysis and verification of the structural performance of an existing
structure determined from a characteristic or another representative value combined with partial and/or
conversion factors, or also directly defined values
3.1.4
damage
unfavourable change in the condition of a structure that can adversely affect structural performance
[SOURCE: ISO 13822:2010, 3.2 — modified]
3.1.5
defect
deficiency of a structure resulting from errors during design, construction, prior intervention or lack of
maintenance
3.1.6
deterioration
process that adversely affects the structural performance, including reliability, over time, for example
due to:
• naturally occurring chemical, physical or biological actions;
• repeated actions such as those causing fatigue;
• wear due to use
[SOURCE: ISO 13822:2010, 3.3 — modified]
3.1.7
deterioration model
mathematical model that describes structural performance as a function of time, taking deterioration into
account
3.1.8
existing structure
structure that physically (materially) exists, including its foundation and soil
3.1.9
heritage structure
existing structure or structural component that has been recognized by the relevant authorities for its
architectural or historical value
Note 1 to entry: Heritage structures can include all kinds of buildings, bridges and civil engineering works,
including their foundations.
3.1.10
inspection
on-site non-destructive examination of a structure and/or its components with the objective of
establishing the present condition of the structure and updating information as relevant
[SOURCE: ISO 13822:2010, 3.5 — modified]
3.1.11
investigation
collection and evaluation of information through inspection, document search, measurements, material
testing, load testing and other testing
[SOURCE: ISO 13822:2010, 3.6 — modified]
3.1.12
load testing
test of a structure or part thereof by loading to evaluate its behaviour or properties, to predict or
determine its load-bearing capacity
[SOURCE: ISO 13822:2010, 3.7 — modified]
3.1.13
material properties
mechanical, physical or chemical attributes of construction materials
[SOURCE: ISO 13822:2010, 3.9 — modified]
3.1.14
material testing
test of construction material to evaluate, or to predict its mechanical, physical or chemical properties
3.1.15
monitoring
frequent or continuous observation or measurement of structural conditions or actions
[SOURCE: ISO 13822:2010, 3.10 — modified]
3.1.16
reference period
chosen period of time which is used as a basis for determining values of variable actions, time-dependent
material properties and relevant reliability
[SOURCE: ISO 13822:2010, 3.11 — modified]
3.1.17
rehabilitation
structural intervention (repair, upgrade) to reach compliance with required structural performance
3.1.18
reliability
the ability of a structure or a structural member to fulfil the specified requirements during its remaining
working life
[SOURCE: EN 1990:2002 — modified]
3.1.19
remaining working life
period for which an existing structure is intended/expected to operate with planned maintenance
[SOURCE: ISO 13822:2010, 3.13 — modified]
3.1.20
structural performance
qualitative or quantitative measure of structural behaviour under expected circumstances in terms of its
safety, serviceability, durability or robustness
3.1.21
target reliability level
the value of reliability that is specified to be achieved in the assessment, indicating that a structure is able
to fulfil its specified requirements over the remaining working life
3.1.22
updating
process of supplementing existing knowledge with new information for assessment
3.1.23
upgrading
modifications to an existing structure to improve its structural performance
[SOURCE: ISO 13822:2010, 3.18]
3.1.24
utilization plan
plan containing the intended use (or uses) during the remaining working life of an existing structure, and
listing the operational conditions of the structure including maintenance requirements, and the
corresponding performance requirements
[SOURCE: ISO 13822:2010, 3.19 — modified]
3.2 Symbols
For the purposes of this document, the following symbols apply.
3.2.1 Latin upper-case letters
is the assessment value of the effect of actions
E
a
characteristic value of permanent action
G
kj,
target probability of failure for a given reference period
P
ft
characteristic value of prestress action
P
k
characteristic value of the leading variable action
Q
k,1
characteristic value of accompanying variable actions
Q
ki,
is the assessment value of the resistance
R
a
V coefficient of variation
characteristic values of the material or product properties
X
ki,
3.2.2 Latin lower-case letters
assessment values of the geometrical data
a
a
k independence period
n reference period
basic variable i
x
i
characteristic value of the basic variable x
i
x
ki
assessment value of the basic variable x
i
x
ai
3.2.3 Greek upper-case letters
φ
cumulative distribution function of the normal distribution
−1 inverse cumulative distribution function of the normal distribution
φ
3.2.4 Greek lower-case letters
sensitivity factor for load effect
α
E
sensitivity factor for resistance
α
R
target reliability index
β
t
partial factor of the variable x
i
γ
ai
partial factor for permanent actions, taking account of unfavourable deviations of the
γ
gj,
action values from the representative values
γ
partial factor for permanent actions, equal to γγ
Gj,
Sa g, j
partial factors to take account of the possibility of an unfavourable deviation of a
γ
mi,
material or product property from its characteristic value and the random part of the
η
conversion factor
γ
partial factors for the material or product properties, equal to γγ
Mi,
Ra m,i
partial factor for prestress actions, taking account of unfavourable deviations of the
γ
p
action values from the representative values
γγ
γ partial factor for prestress actions, equal to

Sa p
P
partial factor for the leading variable action, taking account of unfavourable deviations of
γ
q,1
the action values from the representative values
partial factor for accompanying variable actions, taking account of unfavourable
γ
qi,
deviations of the action values from the representative values
γ
partial factor for the leading variable action, equal to γγ
Q,1
Sa q,1
γ
γγ
partial factor for accompanying variable actions, equal to
Qi,
Sa q,i
γ
γ
partial factor for assessment (corresponding to for design) covering uncertainty in
Ra
Rd
the resistance model, plus geometric deviations if these are not modelled explicitly
γ
γ
partial factor for assessment (corresponding to for design) taking account of
Sa
Sd
uncertainties in modelling the effects of actions, or, in some cases, in modelling the
actions
mean values of the conversion factors, taking into account volume and scale effects,
η
i
effects of moisture and temperature and any other relevant parameters, which can in
γ X
some cases be incorporated in or included in
Mi, ki,
the mean of the basic variable x
i
µ
Xi
the standard deviation of the basic variable x
i
σ
Xi
combination factors for assessment relevant to the accompanying variable actions
ψ
0,i
4 Principles of assessment
4.1 Reliability management
(1) When assessing an existing structure, it shall be verified whether the structure has an adequate level
of reliability.
NOTE 1 For assessment of existing structures, the target value of reliability index β related to a reference period,
t
can be set by the National Annex for use in a country.
NOTE 2 When assessing an existing structure, the target reliability is not necessarily the same as for the design
of a new structure.
NOTE 3 Additional information concerning target reliability levels is given in Annex C.
(2) Different levels of reliability may be adopted for assessment of structural safety and serviceability.
(3) When assessing an existing structure, the risks associated with the structure being damaged to an
extent disproportionate to the original cause by events such as explosion, impact, the consequences of
human errors, or other unforeseen events, should be identified.
NOTE Requirements for the identification and control of risks associated with the structure being damaged to
an extent disproportionate to the original cause in a country can be set by the National Annex for use in a country.
4.2 Methods of assessment
(1) The method of assessment of an existing structure at the relevant limit states shall be either:
• assessment by calculation, or
• assessment based on past performance.
NOTE 1 For assessment by calculation, see Clause 6.
NOTE 2 For assessment based on past performance, see Clause 10.
NOTE 3 The use of testing and monitoring can form part of the assessment using either assessment method (see
7.4, 8.4 and Annex B).
(2) The method of assessment at the relevant limit states should be as agreed for a specific project by the
relevant parties.
4.3 Assessment situations
(1) Assessment situations relevant to the structure and its assessment shall cover the critical conditions
and hazards that can reasonably be foreseen for the remaining working life of the structure.
(2) Assessment situations shall be classified as follows:
• persistent assessment situation (relating to the assessment of the structure according to the normal
conditions of use over the remaining working life);
• transient assessment situation (relating to temporary conditions, e.g. during structural interventions
or modifications);
• accidental assessment situation (relating to accidental actions such as impact, explosion, fire).
4.4 Using available information
(1) Available information from the original design and construction, inspections carried out during the
past working life, and the condition survey and further structural investigations should be taken into
consideration for the assessment of an existing structure.
NOTE 1 For the condition survey and further structural investigations, see 5.5.
NOTE 2 For the determination of basic variables from the available information, see Clause 7.
NOTE 3 Features to be considered to verify the completeness and correctness of the available information can
include: any previous intervention; signs of significant environmental, seismic or other extreme events in the past;
changes in soil conditions; and the influence of deterioration mechanisms.
(2) Relevant national documents that were applicable when the structure was designed may be used to
inform values for some basic variables in the assessment (such as material or product properties, initial
prestress values, prestress losses, etc.).
NOTE Details of relevant national documents can be set by the National Annex for use in a country.
4.5 Updating available information
(1) The values of basic variables may be updated in accordance with Clause 7.
NOTE Updating basic variables can improve the assessment results by removing conservative assumptions.
(2) The structural analysis model may be updated in accordance with Clause 8.
4.6 Structures with new elements and retained elements
(1) For projects where new structural elements are to be combined with retained parts of an existing
structure, the new structural elements should be designed in accordance with EN 1990, EN 1991 and the
relevant material-related Eurocodes.
(2) For projects where new structural elements are to be combined with retained parts of an existing
structure, the assessment of the retained elements shall be in accordance with this document.
NOTE 1 The agreement of which retained elements are to be assessed is covered in 5.3.
NOTE 2 The assessment can consider intermediate stages of construction as transient assessment situations as
well as the persistent assessment situation for the completed structure (see 4.3).
(3) The approach to the verification of a whole structure comprising new and retained elements,
including the coordination of the design of new elements and the assessment of retained elements, the
target reliability level, the design working life, the durability requirements, and the interface design
philosophy, should be as specified by the relevant authority or, where not specified, agreed for a specific
project by the relevant parties.
NOTE Minimum requirements for the verification of a whole structure comprising new and retained elements
can be set in the National Annex for use in a country.
4.7 Assessment of heritage structures
(1) When assessing heritage structures of cultural significance and societally important existing
structures, structural performance and heritage value should both be taken into account in the
assessment and decisions involving possible structural interventions.
NOTE Guidance for the assessment of heritage structures is provided in Annex D.
5 Assessment process
5.1 General
(1) The assessment of a structure should be carried out following a stepped process with increasing levels
of detail and accuracy, as specified by the relevant authority or, where not specified, agreed for a specific
project by the relevant parties.
NOTE 1 The assessment process can typically include: initiating the assessment (see 5.2); agreeing the
assessment scope and objectives (see 5.3); developing the assessment approach (see 5.4); establishing the
structural condition (see 5.5), undertaking the assessment (see 5.6), and reporting the assessment findings (see
5.7).
NOTE 2 The assessment process is illustrated in Annex A.
NOTE 3 The process presented in Clause 5 can be applied to both the assessment of one specific structure and
the assessment of a group of structures.
(2) Where, at any stage of the assessment process, the structure appears to be in a situation that poses a
level of risk that could require immediate intervention to restore safety, this shall be reported to the
relevant authority or relevant parties so that relevant mitigation measures (see Clause 11) can be
implemented immediately.
5.2 Initiating the assessment
(1) Decisions relating to the initiation of structural assessments should be as specified by the relevant
authority or, where not specified, agreed for a specific project by the relevant parties.
NOTE The assessment of existing structures can be initiated under various circumstances such as:
• an anticipated change in use or extension of the design working life;
• changes in the structural system (e.g. retrofitting, modifications, extensions to the structure);
• a change of loads;
• a scheduled assessment as part of an asset management programme;
• structural deterioration due to time-dependent actions (e.g. corrosion, fatigue);
• structural damage caused by accidental events, seismic events, overloads, or induced by other change of
conditions (e.g. settlements);
• defects resulting from previously undetected errors during design or construction.
5.3 Agreeing the assessment scope and objectives
(1) The extent of the structure to be assessed should be as agreed for a specific project by the relevant
parties.
NOTE Minimum requirements for the extent of structures to be assessed can be set out in the National Annex
for use in a country.
(2) The conditions and requirements for the use of the structure and its behaviour during the remaining
working life should be established and recorded, including the following information:
• intended use;
• remaining working life;
• performance objectives concerning structural safety, serviceability, durability or robustness as
relevant;
• operational conditions;
• inspection and maintenance requirements.
NOTE 1 Minimum requirements for the use of structures and their behaviour during the remaining working life
can be set out by the National Annex for use in a country.
NOTE 2 The utilization plan can be used to record the conditions and requirements for the use of the structure.
NOTE 3 Operational conditions can include: maximum in-service wind speed, protection against environmental
influences, etc.
NOTE 4 Inspection and maintenance requirements can include: monitoring, application of protective coatings,
etc.
(3) The conditions and requirements for the use of an existing structure and its behaviour should be
converted into assessment objectives and recorded, including the following information:
• the actions to be included in the assessment;
• the assessment situations to be considered for the structure, including those related to possible
changes in structural conditions or actions;
• requirements for limit states to be assessed (e.g. requirements concerning structural safety,
serviceability, durability or robustness), and the methods of assessment for the relevant limit states;
• risks accepted without any countermeasures (e.g. relatively small risks);
• design provisions of EN 1990 that do not need to be satisfied for assessment, where relevant;
• the format for describing the result of the assessment.
NOTE 1 Minimum requirements for the assessment objectives can be set out in the National Annex for use in a
country.
NOTE 2 Criteria to determine the need for an assessment of serviceability can be set out in the National Annex
for use in a country.
NOTE 3 Assessment of serviceability limit states by calculation can provide useful information for a specific
project, for example: (i) when assessing for a change in use; (ii) when investigating existing serviceability problems;
(iii) when the assessment of structural safety relies on particular serviceability criteria being satisfied.
NOTE 4 For assessment situations, see 4.3.
NOTE 5 For methods of assessment, see 4.2.
(4) The objectives of the assessment of an existing structure should incorporate any requirements
specified by the relevant authority or, where not specified, agreed for a specific project by the relevant
parties.
5.4 Developing the assessment approach
(1) The general approach to be taken for the assessment shall be developed and recorded, including:
• the method of assessment (see 4.2);
• the approach to assessing the effects of structural condition and deterioration (see 5.4(2));
• the assumptions and data to be used in the assessment;
• the structural analysis methodology (see 8.3);
• the approach to assessing the effects of the construction process and subsequent changes to the
structure, where relevant.
NOTE An iterative process can be used to develop and record the approach for the assessment, for example
where the approach for a detailed assessment is developed following a preliminary assessment (see 5.6.2).
(2) The general approach for incorporating the effects of structural condition and deterioration into the
assessment should be agreed for a specific project with the relevant parties.
NOTE 1 Approaches for assessing the effects of structural condition can include:
• assessment of the structure in its current condition;
• assessment of the structure in its current condition and in its anticipated future condition for its remaining
working life.
NOTE 2 The approach taken to assess the effects of condition can depend on the management strategy for the
structure and the risk of future deterioration.
5.5 Establishing the structural condition
5.5.1 General
(1) The condition of the actual structure, including ongoing deterioration mechanisms and existing
defects, shall be established taking into consideration all available information, including prior
experience from comparable structures.
NOTE See 4.4 for the use of available information and 4.5 for updating available information.
5.5.2 Condition survey
(1) A condition survey shall be undertaken to update the knowledge about the condition of the structure,
its principal dimensions and boundary conditions with respect to the aspects that are of importance to
the structural behaviour and reliability.
NOTE 1 The aim of a condition survey is generally to update knowledge about the condition of the structure as
well as to verify the accuracy of as-built information. The main focus is often on those structural members which
most decisively influence the behaviour of the system.
NOTE 2 Visual inspections are generally undertaken to verify the completeness and correctness of the
information available and can be supplemented by quantitative ins
...