Vocational Training in Assessment of Buenos días Existing ...

22.6.2012

1

Vocational Training in Assessment of Existing Structures

Agreement number: CZ/11/LLP-LdV/TOI/134005

1 1

Vocational Training in Assessment of

Existing Structures Agreement number: CZ/11/LLP-LdV/TOI/134005

Milan Holický

Czech Technical University in Prague

Buenos días

2

The first meeting in Prague, 26.10.2011

P1: KI, Applicant co-ordinator, Milan Holicky

P2: SPSS, Associated p., Roman Gottfried

P3: HR, Core partner, Dimitris Diamantidis

P4: IET, Core partner, Angel Arteaga

P5: UOP, Core partner, Pietro Groce

P6: TNO, Associated p., Ton Vrouwenvelder

P7: PAU, Core partner, Selcuk Toprak

22.6.2012

2

The project stimulation

• Existing structures represent a huge economic asset getting larger and larger every year.

• Many existing structures do not comply with the requirements of currently valid codes.

• There is no European code for existing structures lined with Eurocodes.

• The assessment of existing structures requires knowledge beyond the scope of design codes for new structures.

• The ultimate goal is to limit construction intervention to a minimum, thus complying with the principles of sustainable development.

• Authorities, owners and engineers need guidelines how to deal with existing structures

4 4

Main results

30.9.2012

31.5.2013

31.5.2013

31.5.2013

30.11.2012

31.7.2012 31.12.2011 30.9.2013

30.9.2013

30.9.2013

22.6.2012

3

The third meeting in Barcelona

14 to 16 June 2012

Thank you for your attention – Gracias

Why existing structures?

Assessment of an existing structure in many aspects differs from

designing a new structure, the main differences include:

– effects of the construction process and subsequent life,

– alteration, deterioration, misuse, and other changes,

– economic and social aspects.

Two main principles of assessment are usually accepted:

1. Actual characteristics of structural materials, actions,

geometric data and structural behaviour should be

considered.

2. The original design documentation should be used as

guidance documents only and currently valid codes for

verification of structural reliability should be considered.

22.6.2012

4

7 7

Meetings - kick-off meeting, Prague, 26.,27.10.2011

- plenary meeting in Pisa, 8.,9.3.2012

- plenary meeting in Barcelona, 14.15.5. 2012

- plenary meeting in Regensburg, 11.12.10.2012

- plenary meeting in Pisa, 04/2013

- plenary meeting in Denizli, Istambul, Izmir, 06/2013

- final plenary meeting in Prague, 09/2013

Additional meetings between P1, and relevant partners

will be planned depending on work progress.

Bilateral meetings (for example between P1 and P2) or

other upon need.

8 8

Vocational Training in Assessment of

Existing Structures Agreement number: CZ/11/LLP-LdV/TOI/134005

The second meeting in Pisa on 8. and 9.3.2012

22.6.2012

5

The Fourth meeting in Regensburg

11 to 12 October 2012

1

Codes and Recommendations

Project number: CZ/08/LLP-LdV/TOI/134005

Seminar: Assessment of existing structures

Codes and RecommendationsDimitris Diamantidis

Regensburg University of Applied Sciences

• Need and criteria for codes and recommendationsE l d

Barcelona June 14, 20121

• Example codes• Example contents• Safety acceptance – performance criteria• Future tendencies

Structural failures experience

2

Requirements for a code on existing structures

•Applicability: the code should be applicable to typicalassessment casesassessment cases.

• Compatibility to codes for new structures: the codeshould use the same philosophy as current codes fornew structures.

• Flexibility: the code should be flexible to includeadditional information gained by inspection.

E f h d h ld b d d bl• Ease of use: the code should be understandable toengineers and easy to use in practice.

Use of codes for new structures?

• Under what conditions?• Under what conditions?

• Possible relaxations/safety measures?

• Required performance level?

• Uncovered aspects (inspections etc.)?

3

Regulatory tools for existing structures

• What topics are covered?• What topics are covered?

• What type of buildings are dealt with?

• Under which circumstances?

• Used methodologies (prescriptive or risk based)based)

• Specified performance level

Example: Building Code

• 1997 UBC: 2 pages• 1997 UBC: 2 pages

• 2000 IBC: 14 pages

• 2003 International Existing

Building Code:

67 pages +214 pages Anne es67 pages +214 pages Annexes

• 2012 new version 290 pages

4

Why reassess an existing structure?

• Deviations from original design• Deviations from original design

• Doubts about safety

• Adverse inspection results

• Change of use

Lifetime prolongation• Lifetime prolongation

• Inadequate serviceability

Typical questions

• What type of inspections are necessary?

• What type of measurements shall betaken?

• What analyses shall be performed?

• What is the future

risk in using

the structure?

5

How to find the Answers

• No classical code approach• No classical code approach

• New information becomes available

• New techniques can be implemented

• New material technologies can be used

Ne decision criteria nder ne• New decision criteria under new uncertainties

Prenormative and regulatory tools

• ISO 13822 2003• ISO 13822, 2003

• ICC Existing Buildings Code, 2009

• SIA 462 (Switzerland), 1994

• Danish Technical Research Council

• ASCE Seismic Evaluation, 2003

• ACI 437R -03, 2003

• JCSS Recommendations, 2001

6

ISO 13822

• General Framework of AssessmentGe e a a ewo o ssess e t• Data for assessment• Structural Analysis• Verification (Limit State)• Assessment based on satisfactory past performance• Interventions• Report• Report• Judgement and Decisions

New Information (Updating)

A) Proof Load

B) Variables (concrete ) (strength)

7

A) Example: Proof Loading (Survival of a load)> Updating of resistance

B) Example: Concrete strength data

Histogram

20

25

30

35

req

uen

cy

Frequency

Normal

Lognorm "0"

Gumbel

Lognormal

Gamma

0

5

10

15

0 30 42 54 66 78 90 102

F

8

JCSS Recommendations forExisting Structures

• Preface• Preface

• Part 1: General (Guidelines, Codification)

• Part 2: Reliability Updating

• Part 3: Acceptability Criteria

Part 4: E amples and case st dies• Part 4: Examples and case studies

• Annex:Reliability Analysis Principles

Safety Acceptance Criteria

European Experience (limit state- European Experience (limit state verification)

- New practice in the US (performance based design)

- Optimisation based on LQIOp Q

- Judgement

9

Methodology

a) Prescriptive rulesa) Prescriptive rules

(limit state verification by use of safety factors)

b) Performance based designg

(global check of structure)

PBD criteria

<pE . pNP|E < pA

pE :propability of event

pNP|E:conditional probability of no |performance given event

pA :acceptable probability

11

Conclusions regarding risk acceptance

• A lower safety level compared to a new• A lower safety level compared to a new structure is acceptable

• Various criteria have been proposed

• Acceptance criteria depend on cost of safety, consequences of failure, desired residual lifetimelifetime

• An increase of acceptable pF by a factor of 2 to 10 is recommended

Concluding remarks:1. Available codes: General, material, structures dependent2. Covered topics: inspection, maintenance, repair3. Implemented methods: Structural, reliability, collapse analysis

22.6.2012

1

Basic concepts of assessment of existing structures

Milan Holický

Klokner Institute, Czech Technical University in Prague

Background materials ISO, EN, JCSS

1. ISO 2394 General principles on reliability for structures, 1998

2. ISO 13822 Assessment of existing structures, 2008

3. ISO 13823 Design for durability, working draft

4. ISO 13824 Risk Assessment, working draft

5. ISO 12491 Statistical methods, 1997

6. EN 1990 Basis of structural design, 2002

7. EN 13791 Assessment of in-situ compressive strength in structures and precast concrete components, 2007

7. JCSS- RILEM Probabilistic Assessment of Existing Structures, 2001

8. JCSS Probabilistic Model Code, working draft

9. JCSS new activities on risk assessment a robustness, working drafts

10. FIP model code, 2007

22.6.2012

2

When assessment of existing structures ?

- rehabilitation of an existing facility when new structural members are added to the existing load-carrying system;

- adequacy checking in order to establish whether the existing structure can resist loads associated with the anticipated change in use of the facility;

- repair of a structure deteriorated due to time dependent environmental effects or which has suffered damage from accidental actions, for example, impact;

- doubts concerning actual reliability of the structure.

General aspects

The following aspects seems to be the most significant:

- effect of construction, alterations, misuse;

- past performance, damage, deterioration, maintenance;

- actual actions, geometry and material property;

- reliability differentiation (consequences, cost of

safety measures, societal, political and culture aspects).

Assessment is in many aspects different from designing a new structure

ISO 13822

22.6.2012

3

Two main principles

• Actual characteristics of structural material, action (permanent load), geometric data and structural behaviour should be considered.

• Currently valid codes should be considered (models for actions and resistances), codes valid in the period when the structure was designed, should be used as guidance documents.

Main steps of assessment

Assessment is an iterative process consisting of:

• specification of the assessment objectives;

• scenarios related to structural conditions and actions;

• preliminary assessment including recommendations;

• detailed assessment including reliability verification;

• report including proposal for intervention;

• repetition of the sequence if necessary.

22.6.2012

4

Adopted from ISO 13822

General flowof assessment

22.6.2012

5

Target reliabilities indicated in ISO 13822

Target β for the reference period 50 years

1

1,5

2

2,5

3

3,5

4

4,5

1 2 3 4Consequences

Be

ta

EN 1990

JCSS PMC

ISO 2394

small some moderate great

3,8

and “moderate” (ISO) or “normal” (JCSS) relative costs of safety measures

10

22.6.2012

6

The optimum βopt and target in ISO β

ISO, β= 4,3, Table 2

ISO, β = 3,1, Table 2

ISO, β = 1,5, Table 2

βopt

q= 0,01 0,03 0,05

Cf/C1 1 10 100 1 .103 1 .104 1 .105 1 .106

1

2

3

4

5

6

JCSS, β = 4,7, Table 3

11

Probability and data updating

fX(x), fX(x|I)

X

prior distribution fX(x)

updated distribution fX(x|I)

updated xdprior xd

fX(x|I) = C P(I|x) fX(x)updated likelihood prior

22.6.2012

7

Partial factor

Assessment in case of damage

1) Visual inspection

2) Explanation of observed phenomena

3) Reliability assessment

4) Additional information

5) Decision if the reliability is still too low:• accept the present situation for economical reasons;

• reduce the load on the structure;

• repair the building;

• start demolition of the structure.

22.6.2012

8

The final reportThe final report on structural assessment and possible interim reports (if required) should

• be concise and clear and should include

• clear conclusions with regard to the objective of the assessment

• based on careful reliability assessment and cost of repair or upgrading.

A recommended report format is indicated in Annex G to ISO/CD 13822 [2].

Summary

• Assessment of existing structures is in many aspects different from designing a new structure

• Actual characteristics of structural material, action (permanent load), and geometric data should be considered.

• Currently valid codes should be considered (models for actions and resistances). Previously used codes as background documents.

• Target reliability level should be optimized taking into account residual life time, consequences and costs of safety measures.

• Partial factor method and probabilistic methods are recommended.

• Assessment based on satisfactory past performance may be used.

• Final report should include recommendations concerning intervention.

22.6.2012

9

The Charles Bridge in Prague – 650 years

In some cases assessment of existing structures is very difficult

Thank you for your attention - Gracias

17

Motivation of the project

• Existing structures represent a huge economic asset getting larger and larger every year.

• Many existing structures do not comply with the requirements of the EUROCODES

• The assessment of existing structures requires knowledge beyond the scope of design codes for new structures.

• The ultimate goal is to limit construction intervention to a minimum, thus complying with the principles of sustainable development.

• Authorities, owners and engineers need guidelines how to deal with existing structures

22.6.2012

10

The total cost κtot(x,q,n) and reliability index βoptfor q = 0,03 and n = 50 yeras

0 .6 0.7 0.8 0 .9 1 1.1 1 .2 1.30.6

0.7

0.8

0.9

1

1.1

1.2

0

1

2

3

4

5

6

x

κto t(x,q,n)

C f/C 1 =1

C f/C 1 =100

C f/C1 =104

C f/C1= 106

βo p t

βo p t

19

The main issues to be considered

• Terminology of EN 1990 concerning assessment of existing structures (taking into account ISO documents).

• Operational rules of assessment linked to EN 1990 principles and ISO general provisions.

• Additional procedures not included in EN or ISO (e.g. estimation of permanent load of existing structures).

• Reliability differentiation for assessment of existing structures including heritage architecture (revisions of ISO).

• Probabilistic approach to assessment including reliability updating (detailed practical guidance).

22.6.2012

11

Definition of the project Existing structures

• Terms and definitions (additional terms to EN 1990)• General framework (assessment procedures)• Data for assessment (actions, materials, dimensions)• Structural analysis (models, uncertainties, deterioration)• Reliability verification (limit states, target reliabiloities) • Assessment based on satisfactory past performance• Interventions (alternative approaches)• Report (inspection and maintenance)• Annexes (updating, time dependence, target reliability, …)

Material independent document, linked to 1990

Foreseen main chapters

Basic concepts of assessment of existing structures

Milan Holický

Klokner Institute, Czech Technical University in Prague

Backgrounds: EN 1990, ISO 2394, ISO 13822, JCSS, RILEM

22/06/2012

1

Reliability Aspects

Ton VrouwenvelderDelft University / TNO

Leonardo da VinciAssessment of existing structuresProject number: CZ/08/LLP‐LdV/TOI/134005

Reliability

b l f f lf l ll d

EN 1990:

‐ ability of a structure to fulfil all required functions during a specified period of time under given conditions

Failure probability PFailure probability Pf‐most important measure of structural reliability

22/06/2012

2

Limit State Approach

• Limit states ‐ states beyond which the structure no longer fulfils the relevant design criteria

• Ultimate limit states

– loss of equilibrium of a structure as a rigid body

– rupture, collapse, failure

– fatigue failure

• Serviceability limit states

– functional ability of a structure or its part

– users comfort

– appearance

Uncertainties

Density Plot (Shifted Lognormal) - [A1_792]

0.005

0.010

0.015

0.020

Relative frequency

‐ randomness ‐ natural variability

‐ statistical uncertainties ‐ lack of data

model uncertainties simplified models

210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 4200.000

Yield strength [MPa]

‐model uncertainties ‐ simplified models

‐ vagueness ‐ imprecision in definitions

‐ gross errors ‐ human factors

‐ ignorance ‐ lack of knowledge

22/06/2012

3

R

EXAMPLE

R

Resistance: R = d2 fy / 4Load effect: E = V

Failure if E>R or: V > d2 fy / 4Limit state: V = d2 fy / 4

E

y

Limit state function: Z = R-E = d2 fy / 4 - V

R

distribution mean sd R resistance Lognormal 100 10

Statistical models

E

gE load effect Gumbel 50 5

0 .06

P ro b ab ility d en sity E (x ), R (x )

L o ad e ffec t E , G u m bel d is trib u tio n , E = 5 0 , E = 5 R esis tance R

lo g-n o rm al d is trib u tio n ,

40 60 8 0 100 120 1 40 0 .00

0 .02

0 .04

R an d om va riab le X

g R = 10 0 , R = 10

22/06/2012

4

R

distribution mean sd R resistance Lognormal 100 10

Partial factor approach

E

gE load effect Gumbel 50 5

0 .06

P ro b ab ility d en sity E (x ), R (x )

L o ad e ffec t E , G u m bel d is trib u tio n , E = 5 0 , E = 5 R esis tance R

lo g-n o rm al d is trib u tio n ,

E k R k

40 60 8 0 100 120 1 40 0 .00

0 .02

0 .04

R an d om va riab le X

g R = 10 0 , R = 10

Rk/m > Ek Q

Z = R ‐ E

derd)e()r()0Z(PP

R

Probabilistic approach

0)X(Z

ERf derd)e()r()0Z(PP

E Techniques:

Numerical integration (NI)

Monte Carlo (MC)Monte Carlo (MC)

First order Second moment method (FOSM)

Third moment method (accounting for skewness)

First Order Reliability Methods (FORM)

22/06/2012

5

R

First Order Second Moment method

Z = R - E

E

Z = R - E = 100 – 50 = 50

= Z /Z = 3.54

22E

2R

2Z 14σσσ

Pf = P(Z 0) = Z(0) = 0.0002

0,04

Probability density Z(g)

= Z /Z = 3.54 Pf = P(Z 0) = Z(0) = 0.0002

0,02

0,03

1 pf

Z

10 0 10 20 30 40 50 0,00

0,01

Z

pf

22/06/2012

6

Reliability index

Probability of Failure = (‐) 10 ‐

1.3 2.3 3.1 3.7 4.2 4.7

P(F)=(-) 10-1 10-2 10-3 10-4 10-5 10-6

Relation Partial factors and beta‐level:

γ = exp{α β V – kV} 1 + α β V

α = 0.7‐0.8

β = 3.3 ‐ 3.8 ‐ 4,3 (life time, Annex B)

k = 1.64 (resistance)

k 0 0 (loads)k = 0.0 (loads)

V = coefficient of variation

22/06/2012

7

Extensions

• load fluctuations• systems • degradation• inspection• risk analysisy• target reliabilities

Target levels Reliablity

Eurocode EN 1990, Annex B

Reliability index Reliability

classes Consequences for loss of human life, economical, social and environmental

consequences

a for Ta= 1 yr

d for Td= 50 yr

Examples of buildings and civil engineering works

RC3 – high High 5,2 4,3 Important bridges, public buildings

RC2 normal Medi m 4 7 3 8 Residential and officeRC2 – normal Medium 4,7 3,8 Residential and office buildings

RC1 – low Low 4,2 3,3 Agricultural buildings, greenhouses

= exp [(-k)V] ~ 1 + V

22/06/2012

8

JCSS TARGET RELIABILITIES for a one year reference period

Consequences of failure

Minor Moderate Large

Large =3.1 (pF10‐3) =3.3 (pF 5 10‐4) =3.7 (pF 10‐4)

Cost toincrease safety

Normal =3.7 (pF10‐4) =4.2 (pF 10‐5) =4.4 (pF 5 10‐6)

Small =4.2 (pF10‐5) =4.4 (pF 5 10‐5) =4.7 (pF 10‐6)

Cost optimisation / design versus assessment

PF = 10 ‐

22/06/2012

9

Human life safety

• Include value for human life in D

• Still reasons for IR and SR• Still reasons for IR and SR

• Example: p < 10‐4 / year

optimal annual failure probability

0 15

0,2

0,2500

1

0

0,05

0,1

0,15

0 10 20 30 40 50 60

design working time [year]

tim

es 0

,0

Existing Structures (NEN 8700)

Reliability index in case of assessment

Minimum β < βnew – 1.0

Human safety: β > 3.6 – 0.8 log T

22/06/2012

10

Example NEN 8700 (Netherlands)

Minimum values for the reliability index with a minimum reference period

Consequence class

Minimum reference period

for existing building

-NEW -EXISTING

wn wd wn wd

0 1 year 3.3 2,3 1.8 0.8

1 15 years 3.3 2,3 1.8a 1.1a

2 15 years 3.8 2.8 2.5a 2.5a

3 15 4 3 3 3 3 3a 3 3a3 15 years 4.3 3.3 3.3a 3.3a

Class 0: As class 1, but no human safety involved wn = wind not dominant wd = wind dominant (a) = in this case is the minimum limit for personal safety normative

Condition

Inspection en monitoring

limit

Time

22/06/2012

11

Updating

1) Updating distributions (eg concrete strength)

Observations

x x

2) Updating failure probability PF | I

Observations

Information ( I )Rk at design

2) Updating failure probability PF | I Example: I = {crack = 0.6 mm}

see JCSS document on Existing Structures en ISO13822

)P(B)BP(AB)P(A Two types of information I:

equality type: h(x) = 0

inequality type: h(x) < 0; h(x) > 0

)I)P(IP(F I)P(F

)(

)()(

IP IF PIFP

inequality type: h(x) < 0; h(x) > 0

x = vector of basic variables

)0)((

)0)(0)(()(

1

12

thP

thtZPIFP

22/06/2012

12

Fatigue steel structures

Find

d crack a

P(a(t+t) > d | a(t) = .. of a(t)<..)

0.4

0.6

0.8

1.0

PO

D

alpha = 1 ; beta = 3 alpha = 3 ; beta = 10

no cracks found, but? measured 1 mm, but?

0.0

0.2

0

0 5 10 15 20 25

Scheurafmeting [mm]

22/06/2012

13

Reliabilty level Beta (one year periods)given a crack found at t=10 a

8fully correlated

2

4

6

reli

ab

ilit

y in

dex

after inspection

00 5 10 15 20 25

time [year]

without inspection

Updating distributions

P(x|I) = P(x) P(I | x) / P(I)

fX (x|I) = C fX(x) P( I | x)

fX(x), fX(x|I)

updated distribution fX(x|I)

updated prior likelihood

X

prior distribution fX(x)

updated xdprior xd

22/06/2012

14

)L()fC)|(f |ˆ|(ˆ '''

Formal Updating formulas

q)xL(q)fC)x|(qf QQ ||(

dq)x|(qfqxfxf QXUX

ˆ)()( ''

)L()fC)|(f |ˆ|(ˆ '''

Formal Updating formulas

q)xL(q)fC)x|(qf QQ ||(

dq)x|(qfqxfxf QXUX

ˆ)()( ''

Ask the expert !

22/06/2012

15

Example: Resistance with unknown mean mR and known stand. Dev. sR =17,5

Assume we have 3 observations with mean mm = 350Then mR has sm = 17,5/√3 = 10.If the load is to 304 then:

mZ= 350‐304=46sZ =(17,52 +102) = 20,2=2,27Pf=0,0116

Now we have one extra observation equal to 350.In that case the estimate of the mean mm does not change. h d d d f h h /( )The standard deviation of the mean changes to 17,5/(4) = 8,8

mZ= 350‐304=46,sZ =(17,52 +8,82) = 19,6,=2,35Pf=0,0095

Summary Reliability aspects

Uncertainties exist

Probability Theory may be helpful

Reliability targets depends on consequences of failure

Reliability targets depend on costs of improving

Existing structures may have a lower target reliabilityg y g y

Reliability may be updated using inspection results

There is a relation partial factor – reliability index

1

Assessment and Procedures


Seminar: Assessment of existing structures

Assessment and ProceduresDimitris Diamantidis

Regensburg University of Applied Sciences

• Assessment process

Barcelona June 14, 20121

• Phases and procedures• Decision criteria• Examples

Assessment Process

2

Phase 1: Preliminary Assessment

• Visual inspection• Visual inspection

• Review of documentation

• Code compatibility

• Scoring system:1. age of the structure

2. general condition

3. loading (modifications)

4. structural system

5. residual working life

Phase 2: Detailed Assessment

• Quantitative inspections• Quantitative inspections

• Updating of information

• Structural reanalysis

• Reliability analysis

• Acceptance criteria

Histogram

30

35Frequency

Normal

Lognorm "0"

Gumbel

Lognormal

Gamma

0

5

10

15

20

25

0 30 42 54 66 78 90 102

Fre

qu

ency

Gamma

3

Phase 3: Expert team asessment

• Additional inspections• Additional inspections

• More detailed analyses1. progressive collapse

2. full probabilistic

3. sensitivity analyses

4 risk analyses4. risk analyses

Decision Criteria

• Target reliability• Target reliability

• Economical considerations

• Time constraints

• Sociopolotical aspects

Codes and standards• Codes and standards

• Complexity of analysis

• Experience in other fields

4

Old Railway Bridges(single span systems)

Railway Bridges

• 100 years old• 100 years old• Scoring system

verification (foundation, corrosion, joints, supports)

• R (steel resistance) from code on old bridgescode on old bridges

• S (train load) from DB(German Railways)

• Durability problems

5

Example Concrete floor structure(Phase 2 Procedure)

Reassessment of r.c. floor structure

flexural limit state functionflexural limit state function

g = Mu - Ma

Mu: Ultimate Bending Moment

Ma: Acting Bending Moment

6

Two Cases for Updating

• Case a) Updating of random variables• Case a) Updating of random variables

(due to destructive tests)

• Case b) proof load = 4x design load

Variable Distribution c.o.v.

Steel strength

Lognormal 0.06

Case a) Updating of random variables(due to destructive tests)

strengthg

Concrete Strength

Lognormal 0.14

Cover thickness

Lognormal 0.25

i i i i ß i i f 3 0Reliability index ß is increased from 3.70(prior information) to 3.80, due to

reduced variability of the parameters

7

Case b) proof load

• Partial proof test until collapse resulted to a• Partial proof test until collapse resulted to a very high proof load

• Artificial limit state function

g = Mproof – Mu<=0

• Computation of conditional failure probability

=> Reliability index ß is increased from 3.70

to 4.90

Typical limit states

- extreme load

Steel road bridges

(Phase 3 Procedure)

- extreme load

- Fatigue

Which measures are necessary in order to meet acceptance criteria (residual life time 20 years)?

8

Fatigue models

• Fracture Mechanics approach• Crack growth propagation• Influence of inspections (measurement of

cracks)

Sr25m 30m 25m

2ca

Wf

A

Bb

2c

Sr

Wf

b

WcpL

5m

Detail locationCover plate detail

Variable Distribution Type

ad POD* Inspection

Fatigue assessment: Random Variables (examples)

0 8

0.9

1

DetectionP b bili

DPI

ag Uniform Repair

afail Derived Mixed

Sr RayleighLoad

Smax Gumbel

* POD for MPI used in case study

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.5 1 1.5 2 2.5 3 3.5

Crack size (mm)

Probability

ECT

CWMPI

ACFM

9

1,00E-01

1,00E+00

GIADI

DI

Fatigue assessment: typical results

1,00E-04

1,00E-03

1,00E-02

Pf

GIADI

LTIADI

GLTIADI

Prior

1,00E-05

30 60 90 120T (Years)

I: Inspection, D=DetectionIA: Invasive Action, LT=Load Truncation, G=Weld Toe Grinding

• Inspection and crack detection at T=30y

Alt ti id d

Fatigue assessment: scenarios

• Alternatives considered:1. Load truncation (LT)

2. Weld toe grinding (G)

3. Load truncation + weld toe grinding (LT+G)

LEONARDO DA VINCI PROJECT CZ/11/LLP-LdV/TOI/134005

SEMINAR ON ASSESSMENT OF EXISTING STRUCTURES Barcelona. 14-06-2012

ON THE ASSESSMENT OF DETERIORATING STRUCTURES

Peter Tanner. Carlos Lara. Miguel Prieto

Assessment of existing structures

MOTIVATION

– The need to assess the reliability of an existing structure may arise from different causes

– All can be traced back to doubts about the structural safety– All can be traced back to doubts about the structural safety

Reliability ok for future use ?

Staged evaluation procedure, improving accuracy of data

Influence of updated information

ASSESSMENT WITH PARTIAL FACTOR METHOD

– Probabilistic methods are most accurate to take into account updated information

But they are not fit for use in daily practice– But they are not fit for use in daily practice

– Partial factor method should be available for assessment

kact,E E act,act,kR

act,R

Influence of updated information

ASSESSMENT WITH PARTIAL FACTOR METHOD

– Updated characteristic value of X

f(X) Updated information

XXX

Prior information

information

– Updated partial factor X,act

Can not be derived directly

Link between probabilistic and partial factor methods: design point, the most probable failure point on LS surface

XkXk,act

kact,E E act,act,kR

act,R

Work done for sound structures

DEVELOPMENT OF PRACTICAL TOOLS FOR THE ASSESSMENT

– Identification of representative failure modes and LSF

– Adoption of partial factor format for assessment

Definition of reference period– Definition of reference period

– Deduction of default probabilistic models

– Establishment of required reliability

– Updating of characteristic values and partial factors

Xd,act (PDF; X,act; X,act; X,act; req)Updated

f(X)

X

Default model, Xk

pmodel, Xk,act f(X)

X

Xact*Xd,act

Xk,act

X

X


– IntroductionIntroduction

– Updated models for the assessment of sound structures

– Corrosion-damaged reinforced concrete structures

– La Laguna cathedral

– Final remarks

Tools developed

PARTIAL FACTOR FORMAT FOR ASSESSMENT

– Design value for action effects

t1kt1tjktjtSdtd ""Q""GEE

Updated partial factor for actions (statistical variation)

Updated partial factor for the models for action effects and for the simplified representation of actions

– Model uncertainties vary depending on the action effects disting ish bet een

i,act,fSd,act

1jact,1,kact,1,qact,j,kact,j,gact,Sdact,d ...QGEE

distinguish betweenBending moments

Shear forces

Axial forces

– Format differs from EC but is more accurate for evaluation

M,act,SdV,act,SdN,act,Sd

Tools developed

PARTIAL FACTOR FORMAT FOR ASSESSMENT

– Design value for resistance

tdact,i,k

itd a;X1

R

Updated partial factor for the material or product property

Updated partial factor for the resistance model

– Model uncertainties vary depending on the resistance mechanism distinguish between (RC structures)

m,i,actRd,act

act,dact,i,m

iact,Rd

act,d a;R

Bending moments

Tensile forces in the web

Diagonal compression forces in the web

Axial compression forces

– Format differs from EC-2 but is more accurate for evaluation

M,act,Rd

N,Rd

sV,Rd

cV,Rd,act

,act

,act

Tools developed

DEFAULT PROBABILISTIC MODELS COMPLYING WITH THE FOLLOWING REQUIREMENTS

– Representation of physical properties of the corresponding variable 4

5

6Gumbel Probability Plot

of the corresponding variable

– Consistency with JCSS models

– Representation of the state of uncertainty associated with code rules

Representation of

f(X)

30 40 50 60 70 80 90 100 110-3

-2

-1

0

1

2

3

X

-log(

-log(

F))

– Representation of uncertainties by means of random variables, suitable for practical applications

X

X

X

Xk

XFORM

Xd = X·Xk

ii XXi TypeX ;

Tools developed

2.50

UPDATED PARTIAL FACTORS

– For example partial factor for concrete strength versus CoV

0.50

1.00

1.50

2.00

c

V i bl d i t

0.00

0 0.1 0.2 0.3 0.4 0.5 0.6Vc

V ariable dominante

No Dominante

act,d

act,i,m

act,i,ki

act,Rdact,d a;

X1R

Comparable

Definition

EC-2,cRdc EC-2,cc

EXAMPLE

– Assessment of existing RC structure for new conditions

– Site data collection has been decided, planned and carried out

Assessment with site-specific models

carried out

Sample of n test results is available for updating of reinforcement yield strength, fys

M-M+

PROCEDURE

1. Statistical evaluation of results of observations

PDF: f (x)

f(fys) Tests


PDF: fX(x)

2. Combination of the f(fys) Tests

fys

2. Combination of the results of observations with the available prior information (default probabilistic models)

fys

Default model

Updated information

PROCEDURE

3. Description of the updated distribution function by means of relevant parameters: Type; X,act; X,act; xk,act


f(fys)

fys,act

Updated information

Type: LN

4. Coefficient of variation for the relevant function of updated random variables, depending on the partial factor format for assessment

fys,act

fysfys,k,act

EXAMPLE

– Partial factor for reinforcing steel takes into account– Uncertainties related to the yield strength, fys

– Uncertainties related to the cross-sectional area, A


Uncertainties related to the cross sectional area, As

– fys and As enter the LSF as a product: tensile force

– Only fys has been updated

sysys AfF

ys

– Updated coefficient of variation for the tensile force2As

2act,fysact,Fys VVV

act,fys

act,fysact,fysV

Default value

02.0VAs

PROCEDURE

5. Updated partial factor, considering the updated variable dominating or non dominating (unknown in advance)


1.0

1.1

1.2

γs

γs,act,δ

γs,act,ν

0.8

0.9

0 0.025 0.05 0.075 0.1 0.125VFys

Dominating

Non dominating

VFys,act

PROCEDURE

6. Verification of structural safety with updated characteristic values and partial factors: xik,act; Xi,act


1.1

1.2

γs,act,δ

0 2

0.4

0.6

0.8

1.0Xrm

fys

d

fc

As

Vigas de cubierta Hormigón armado Momentos flectores

Regresión polinomial

Dominating variable unknown in advance trial and error or considering x

0.8

0.9

1.0

0 0.025 0.05 0.075 0.1 0.125

γs

VFys

Dominating

Non dominating

γs,act,ν

VFys,act -1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0 0.2 0.4 0.6 0.8 1

As

b1

Mc

Mp

Xem

Mq2

Número de vigas: 240

EXAMPLE

– Verification of bending resistance of RC element

– Only fys has been updated

D i ti i bl F


– Dominating variable: Fys

– Verification of structural safety: act,Rdact,Ed MM

b1

f

fA5.0d

fA1M

ckc

c

2

,act,s

act,k,yss

,act,s

act,k,yss

M,Rdact,Rd






– Final remarks

Performance of corroded elements

MAIN EFFECTS OF CORROSION OF REINFORCEMENT BARS

1. Decrease of bar cross-section

2. Decrease of ductility of steel u reduction of 30 to 50%)

3. Bond deterioration

4. Cracking of concrete cover (due to corrosion products)

3

4

corrosion prod cts

sound steel

a/2

cover, d

Corrosion may affect performance at ULS and SLS

concrete

1

2

products

a/2diameter, 0

ASSUMPTIONS

– Lower bound theorem of the theory of plasticity is validA load system, based on a statically admissible stress field which nowhere violates the yield condition is a lower bound to the


ycollapse load.

– Stress field models can be establishedMuttoni et al., 2011

– Required information – Geometry, particularly remaining bar cross-sections

– Material properties

– Bond strength

SITE DATA COLLECTION

– Geometry and material properties can be updated


BOND STRENGTH

– Pull-out tests on specimens with accelerated and natural corrosion

Normalized bond strength depending on cross-section loss


Normalized bond strength depending on cross-section loss

8 0

10,0

12,0M. Prieto (corr > 5%)

M. Prieto (corr < 5%)

M. Prieto (No corrosion)

Lineal (corr > 5 %)

Lineal ( corr < 5 %)

Lineal (No corrosion)

Normalized bond strength for corroded bars

Linear Regression (corr > 5 % )

Linear Regression (corr < 5 % )

Linear Regression (No corrosion)

95 % fractile

0,0

2,0

4,0

6,0

8,0

0 1 2 3 4 5 6 7 8

τ/f ctm

a/

95 % fractile

5 % fractile

5 % fractile

5 % fractile

95 % fractile


SIMPLE MODELS FOR ESTIMATE OF PERFORMANCE OF CORRODED STRUCTURAL ELEMENTS

– Example: bending resistance

A

A

environmental action

Upper bound: active

Lower bound: disregarded(spalling)

A - A

Similar rules for other failure modes and SLS 0

aa/2

a/2

As(t) = n (0 - a(t))2

4

ESTIMATION OF MODEL UNCERTAINTIES

– Available tests from a research project on the residual service life of RC structures [Rodríguez et al.]

– Bending tests on 41 beams some with accelerated corrosion

Validation of the model

– Bending tests on 41 beams, some with accelerated corrosion

2,3

Cross-sectional loss:Top < 30,3%Bottom 9,75% to 26,4%0,2

– Bending failure in 25 beams, 15 with corroded reinforcement

– Material properties and geometry have partly been determined for the tested beams

Estimation of model uncertainties

PARAMETERS FOR UNCERTAINTY VARIABLES

– Comparison test – model and statistical evaluation of results

U b d ti


Model

L b d

Distribution

LN

1 34

CoV

0 11

Upper bound: active

Lower bound: disregarded

Remaining cross-sections

– Model for lower bound is conservative

– Lower precision than in bending strength models for sound beams reasonable

Lower boundUpper bound

LNLN

1,340,97

0,110,11

CONSEQUENCES

– Higher model uncertainties lead to increase in pf

– Partial factor should be increased

X


Further studies are required, for example for members with– Larger dimensions

– Natural corrosion

act,d

act,i,m

act,i,ki

act,Rdact,d a;

X1R

ONGOING TESTS

– Industrial building in the northwest of Spain – Construction from the 40’s of the last century

– In disuse for 20 years


In disuse for 20 years

– Exposure to marine environment during 70 years

– Change of use– Transformation into cultural centre

Partial demolition required

ONGOING TESTS

– Selection of representative, corrosion-damaged members for testing

– 8 beams


8 beams

– 5 columns

– 1 frame

FIRST RESULTS

– Bending test on beam nº 1– Deformation control

– Ductile behaviour

A - A


Ductile behaviour

LVDT-2LVDT-1

A

80

100

120Ensayo de flexión 4 puntos viga 1 (LVDT-2)

4,84

1,0 1,0A

0

20

40

60

80

0 5 10 15 20 25 30 35 40 45 50

Ca

rga

(k

N)

Flecha (mm)

THEORETICAL LOAD BEARING CAPACITY

– Prior information – Geometry: measured on tested beam prior to the test

– Material properties: determined for members from the same


Material properties: determined for members from the same building

– Analysis based on prior information using stress field model and comparison to test

– Mult,t = 127 kNm

– Mult,e = 123 kNm

Muttoni et al., 2011






– Final remarks

SAN CRISTÓBAL DE LA LAGUNA

– Historic city located in Tenerife

– Typical urban structure developed in Latin America during colonisation

Context

colonisation

Declared a UNESCO World Heritage Site in 1999

CATHEDRAL

– Built over former church of Nuestra Señora de los Remedios

– Cathedral since 1818

Declared in ruins in 1897 due to settlements induced damage

Context

– Declared in ruins in 1897 due to settlements induced damage

Except neo-classical facade, it was completely demolished

CATHEDRAL

– Rebuilt between 1905 and 1913 in neo-gothic style according to engineering drawings by José Rodrigo Vallabriga

– Novel technology was used: reinforced concrete

Context

– Novel technology was used: reinforced concrete – Shorter construction time

– Lower costs

RISKS ASSOCIATED WITH SCANTILY PROVEN TECHNOLOGY

– Aggregates with inbuilt sulfates, chlorides, seashells, ...

– Concrete with high porosity and low resistivity

High relative humidity and filtration of rainwater

Motivation

– High relative humidity and filtration of rainwater

Ongoing deterioration mechanisms with severe damage to both, concrete and reinforcement

– Corrosion

– Spalling

– ...

RISKS ASSOCIATED WITH SCANTILY PROVEN TECHNOLOGY

– Less than 100 years after reconstruction, the cathedral was to be closed to the public again and was propped ...

Detailed assessment showed

Motivation

Detailed assessment showed – Impossibility to detain deterioration mechanisms

– Technical difficulties and uncertainties entailed in repairing roof

Recommendation to demolish and rebuild the roof maintaining the rest of the temple

WORLD HERITAGE SITE

– Authorities wish to save the existing main dome

– For this purpose, durability requirements are reduced Service period for normal building structures not for

Motivation

– Service period for normal building structures, not for monumental buildings

Future techniques might be suitable to fully detain deterioration mechanisms

GEOMETRY

– Global system

Description

1010

5,4

7,5

Spherical dome

Cylindrical “drum”

Lantern

– Structural members of the spherical dome – 8 arches

– Shells

– Tension ring

STRUCTURAL BEHAVIOUR

– No significant seismic actions

– Distributed loads produce mainly membrane forces

Thrust is equilibrated by tension ring forces

Description

– Thrust is equilibrated by tension ring forces

Mainly vertical loads are transmitted to the robust cylindrical “drum”

Assessment focuses on the dome

PRIOR INFORMATION

– Previous assessment of the existing building, particularly the lower roof

– Available information about

Information

– Available information about – Material properties

– Cross sections of main elements

– Deterioration mechanisms

Prior information for the main dome

DATA ACQUISITION PROGRAM

– Geometry – Overall system dimensions

– Cross sections of structural and ornamental elements

Information

Cross sections of structural and ornamental elements

– Self weight and permanent actions

– Material properties

– Qualitative and quantitative determination of damage

– Cracks

S lli

Outside Inside

– Spalling

– Carbonation and chloride ingress

– Corrosion velocity and cross section loss

– Material deterioration such as crystallization of salts, efflorescence, humidity

– Previous interventions

CROSS SECTIONS

– Parameters for different variables derived from a minimum of 4 measurements

Updated models

hNi,

2

hNi 1

hNi,3

h

hNi

As1,N As2,N

hm

3,L

bm,N

r2As

1,N

hm2

,N

riAs1,N

hl1 L

hl2,L

As,L

Nervio interior

Lámina

b1,Ni b3,Ni

bNi

b2,Ni

Ni,1

bNe

hNe

hL

rlAs1,N

rldAs2,N

r1As1,N

rAs2,N

rliAs2,N

hm1,L

hc,L

l1,L

rAs,L

Nervio exterior

A A

CROSS SECTIONS

– Equivalent cross sections for structural analysis

Updated models

0 19

Arches Shell

0,12

0,20

Ø13

Ø20

Ø20

0,19

0,06 0,06 0

,02

0,0

5

0,0

4

0,08

0,03

1Ø6c./0,22

1Ø6c./0,09

0,11 0,15

Tension ring

0,26

0,77 0,74As,T = 1.592 mm2

SELF WEIGHT AND PERMANENT ACTIONS

– For each layer, j, establishment of – Thickness, hj

– Density of material, j

Updated models

Density of material, j

Mean values and coefficients of variation for self weight and permanent actions

Updated partial factors, for example for self weight

06,1

18,11

,,

,,,,,

2,

2,,,

NENE

cccc

VNSdactNSd

acthactgactg

e

VV

MATERIAL PROPERTIES FOR REINFORCING STEEL

– Manufacture of specimens

– Execution of tensile tests

Updated models

MATERIAL PROPERTIES FOR REINFORCING STEEL

– Evaluation of test results and combination of information

Updated models

0.1Prior PDF

0

0.02

0.04

0.06

0.08

220 240 260 280 300 320

Tests

Predictive PDF

– Updated parameters: LN; fys,act; fys,act; fys,k,act; s,act

– Updated characteristic values– < 6 mm: fys,k,act = 304 N/mm2

– > 6 mm: fys,k,act = 262 N/mm2

fy [MPa]

MATERIAL PROPERTIES FOR CONCRETE

– Manufacture of specimens

– Execution of compression tests

Updated models

10

15

20

25

mp

resi

ón

(M

Pa)

Testigo 5645 T-102-A Galga 2

Rampa 1

Rampa 2

Rampa de rotura

0

5

-2500 -2000 -1500 -1000 -500 0

co

m

(x 10-6)

MATERIAL PROPERTIES FOR CONCRETE

– Evaluation of test results and combination of information

– Updated parameters Compressive strength: LN; ; ; f ;

Updated models

– Compressive strength: LN; fc,act; fc,act; fck,act; c,act

– Modulus of elasticity: Ec,act; Ec,act

– Updated characteristic values– Arches: fck,act = 6,8 N/mm2

– Shells: fck,act = 3,1 N/mm2

– “Drum”: fck,act = 4,9 N/mm2

REINFORCEMENT CORROSION

– Corrosion rate measurements require careful interpretation

– Mean velocity to be estimated from remaining cross sections

Updated models

P ti t M l it

t [years]

da/dt [m/year] a [m]

t [years]

acr

ai+1

a0

Initiation Propag.

dt

Propagation rate Mean velocity

Extrapolation for future service period: As,corr

Winter Winter

Td Ti Ti+1

t [years] t [years]

t0 tp

Td Ti Ti+1

TENSION RING AS AN EXAMPLE

– Relevant design situation for structural safety – Permanent actions and influences

Self weight structural elements

Structural analysis

Self weight structural elements

Self weight ornamental elements

Corrosion

– Leading variable action

Temperature increase

– Accompanying variable action

Wind

Non linear FE analysis

TENSION RING AS AN EXAMPLE

– Updated design action effects NEd,act = 175 kN

– Updated design resistance at the end of future service period

Verification of structural safety

– Updated design resistance at the end of future service periodNRd,act = 363 kN

– Verification NEd,act < NRd,act

RECOMMENDATION

– Structural reliability can be verified, but – Severe damage to concrete and reinforcement

– Impossibility to detain deterioration mechanisms

Decision

Impossibility to detain deterioration mechanisms

– Technical difficulties and uncertainties entailed in repairing dome

Demolition and reconstruction of the roof is advisable






– Final remarks

FINAL REMARKS

– In the safety assessment of existing structures, many uncertainties may be reduced

– Probabilistic methods are most accurate to take into

On the assessment of deteriorating structures

– Probabilistic methods are most accurate to take into account site-specific data

– Such methods are not fit for use in daily practice

– Rational decision making should be possible by using a partial factor format for assessment

Xd,act (PDF; X,act; X,act; X,act; req)Updated

f(X)

X

Default model, Xk

pmodel, Xk,act f(X)

X

Xk,act

X

X

Xact*Xd,act

FINAL REMARKS

– Tools have been developed to accommodate site-specific data by updating characteristic values and partial factors

– Further efforts are needed to extend these tools to the

On the assessment of deteriorating structures

– Further efforts are needed to extend these tools to the assessment of deteriorating structures

June 14-15, 2012 1

SEISMIC SEISMIC PERFORMANCE EVALUATION PERFORMANCE EVALUATION OF OF REINFORCED CONCRETE BUILDING REINFORCED CONCRETE BUILDING

IN IN TURKEYTURKEY

Assoc. Prof. Dr. Mehmet INELPamukkale University, Denizli, TURKEY

Leonardo da VinciAssessment of existing structures


June 14-15, 2012 2

OutlineOutline

Observed damages in past earthquakes

Turkish Earthquake Code-2007

Seismic Evaluation of a Typical School Building

Field Assessment

Office Work

Discussion of Results Observed Concrete Strength in Existing Buildings

June 14-15, 2012 3

Destructive Earthquakes in TurkeyDestructive Earthquakes in Turkey

Date(dd/mm/yy) Magnitude Location # of

deaths# of injured

# of heavily damaged buildings

Latitude (N)

Longitude (E)

Depth (km)

13.03.1992 Ms = 6.8 Erzincan 653 3 850 6 702 39.68 39.56 27

01.10.1995 Ms = 5.9 Dinar 94 240 4 909 38.18 30.02 24

27.06.1998 Ms = 5.9 Adana Ceyhan 146 940 4 000 36.85 35.55 23

17.08.1999 Ms = 7.4 Kocaeli 15 000 32 00050 000 or 100

000 residences

40.70 29.91 20

12.11.1999 Mw = 7.2 Duzce 845 4 948 15 389 40.79 31.21 11

03.02.2002 Mw = 6.5 Afyon-Sultandagi 42 325 4 401 38.46 31.30 6

01.05.2003 Mw = 6.4 Bingol 176 521 1 351 38.94 40.51 6

June 14-15, 2012 4

General ObservationsGeneral Observations

Mid-rise RC buildings with low technology engineered residential construction have been responsible for considerable life and property losses during seismic events

Structural damages were mostly due to repetition of well known mistakes of the past in the design and construction of reinforced concrete buildings

Damaged buildings generally had irregular structural framing, poor detailing, and no shear walls

Turkey has a modern seismic code that is compatible with the codes in other seismic countries of the world

June 14-15, 2012 5

General ObservationsGeneral Observations ((Cont’dCont’d))

Altering the member sizes from what is foreseen in the design drawings

Poor detailing which do not comply with the design drawings

Inferior material quality and improper mix-design

Changes in structural system by adding/removing components

Reducing quantity of steel from what is required and shown in the design

Poor construction practice

June 14-15, 2012 6

Turkish Earthquake CodeTurkish Earthquake Code--20072007

Following 1999 Kocaeli Earthquake, many strengthening and retrofit of damaged buildings are carried out without any fundamentaldocument.

TEC-2007 includes a chapter for performance evaluation and seismic retrofit of existing structures adapted from FEMA-356.

June 14-15, 2012 7

Seismic Retrofit in TurkeySeismic Retrofit in Turkey-- Current Stage Current Stage Public Buildings: Hospitals, School and other public

buildings

Urban development –Urban transformation law in order to minimize potential earthquake losses.

June 14-15, 2012 8

Evaluation of a Typical Public BuildingEvaluation of a Typical Public Building Seismic Evaluation Steps

Building properties: geometry and element size

Material properties: concrete strength and steel properties, soil properties

RC element properties; amount of longitudinal and lateral reinforcement

Existing damage state

Laboratory work to determine concrete strength and soilproperties

Modeling of building

Performance assessment

June 14-15, 2012 9

Evaluation of a Typical Public BuildingEvaluation of a Typical Public Building Seismic Performance Evaluation

Whether the buildings satisfy performance objectives?

Seismic retrofit and strengthening required, economical / not economical, demolish and reconstruct.

June 14-15, 2012 10

TypicalTypical SchoolSchool BuildingBuilding

June 14-15, 2012 11

Foundation Details and Soil PropertiesFoundation Details and Soil Properties

June 14-15, 2012 12

Reinforcement DetailsReinforcement Details

June 14-15, 2012 13

Reinforcement DetailsReinforcement Details

June 14-15, 2012 14

Concrete StrengthConcrete Strength: : Core SamplesCore Samples

June 14-15, 2012 15

FinishingFinishing--ReparingReparing MortarMortar

June 14-15, 2012 16

Laboratory Testing of Core SamplesLaboratory Testing of Core Samples

June 14-15, 2012 17

ModellingModelling

June 14-15, 2012 18

Story Plan ViewStory Plan View

FRP

June 14-15, 2012 19

Performance EvaluationPerformance Evaluation

Deformation

Forc

e

A

B

C

D E

IO LS CP

June 14-15, 2012 20

Performance EvaluationPerformance EvaluationPerformance Level

Performance Criteria

Immediate Occupancy (IO)

1.There shall not be any column or shear walls beyond IO level. 2.The ratio of beams in IO-LS region shall not exceed 10% in any story. 3.There shall not be any beams beyond LS.4.Story drift ratio shall not exceed 0.8% in any story.

Life Safety (LS)

1.In any story, the shear carried by columns or shear walls in LS-CP region shall not exceed 20% of story shear. This ratio can be taken as 40% for roof story. 2.In any story, the shear carried by columns or shear walls yielded at both ends shall not exceed 30% of story shear. 3.The ratio of beams in LS-CP region shall not exceed 20% in any story.4.Story drift ratio shall not exceed 2% in any story.

Collapse Prevention (CP)

1.In any story, the shear carried by columns or shear walls beyond CP region shall not exceed 20% of story shear. This ratio can be taken as 40% for roof story.2.In any story, the shear carried by columns or shear walls yielded at both ends shall not exceed 30% of story shear.3.The ratio of beams beyond CP region shall not exceed 20% in any story. 4.Story drift ratio shall not exceed 3% in any story.

June 14-15, 2012 21

June 14-15, 2012 22

Concrete Strength in Existing Public BuildingConcrete Strength in Existing Public Building

Core samples taken from public buildings (schools, hospitals, etc) to evaluate concrete strength in existing building stock

Prepared for testing and subjected to uniaxialcompression in laboratory

Results converted into compressive strength of standard cylinder (150x300 mm)

1684 core samples tested from 168 buildings

June 14-15, 2012 23

Concrete Strength (AvgConcrete Strength (Avg.. Values)Values)

Avg=141.9

Avg-StDev=97.4

Avg+StDev=186.4

0

50

100

150

200

250

300

350

0 50 100 150 200Bld. Id.

fc (k

g/cm

2 )

June 14-15, 2012 24

COVCOV

Avg=0.24

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 50 100 150 200

Build. Id.

CoV

ar

June 14-15, 2012 25

Date of ConstructionDate of Construction

0

50

100

150

200

250

300

350

1930 1950 1970 1990 2010

Date Of Construction

fc (k

g/cm

2 )

163.0 122.5167.4

194.9

131.2

151.0

94.0

222.9

111.9

0

50

100

150

200

250

300

350

1930 1950 1970 1990 2010

Date Of Construction

fc (k

g/cm

2 )

June 14-15, 2012 26

STATISTICSSTATISTICS

29024520015511065

20

15

10

5

0

fc

Perc

ent

Loc 4.908Scale 0.3064N 168

Lognormal fc (All Buildings)

400

300

200

150

1009080706050

99.9

99

9590

80706050403020

105

1

0.1

fc* (A1&A2&A3)

Perc

ent

Loc 4.908Scale 0.3064N 168AD 0.808P-Value >0.250

Normality Check for fc distribution (All Buildings)Lognormal - 95% Confidence Interval

0.010

0.008

0.006

0.004

0.002

0.000

fc

Den

sity

91.4

0.9

Lognormal, Loc=4.9083, Scale=0.3064, Thresh=0Distribution Plot of fc (All Buildings)

June 14-15, 2012 27

STATISTICSSTATISTICS

2402101801501209060

25

20

15

10

5

0

fc

Perc

ent

Loc 4.782Scale 0.2297N 93

Lognormal fc (1970<Buildings<1990)

24021018015012090

40

30

20

10

0

fc

Perc

ent

Loc 5.075Scale 0.1934N 24

Lognormal fc (Buildings<1970)

300250200150100

25

20

15

10

5

0

fc

Perc

ent

Loc 5.068Scale 0.3228N 51

Lognormal fc (Buildings>1990)

June 14-15, 2012 28

Concrete Strength in Existing BuildingConcrete Strength in Existing Building

After May 19, 2011 Simav Earthquake, buildingswith moderate damage are investigated

Core samples taken from 148 buildings withmoderate damage

Prepared for testing and subjected to uniaxialcompression in laboratory

Results converted into compressive strength of standard cylinder (150x300 mm)

About 1600 core samples tested from 148 buildings

June 14-15, 2012 29

Concrete Strength (AvgConcrete Strength (Avg.. Values)Values)

0

2

4

6

8

10

12

14

16

18

20

22

0 25 50 75 100 125 150

In-s

itu c

oncr

ete

stre

ngth

(M

Pa))

Building ID

7 MPa

June 14-15, 2012 30

Concrete Strength Concrete Strength DistributionDistribution

0

5

10

15

20

25

30

35

<5 5-6 6-7 7-8 8-9 9-10 10-12 >12

Num

ber o

f O

ccur

ence

Concrete Strength Range (MPa)

Vocational Training in Assessment of Buenos días Existing ...

Documents

Transcript of Vocational Training in Assessment of Buenos días Existing ...