fib 2006

Regression Based Criteria Determining for Preservation Strategies of Early RC Buildings

Maria BOSTENARU DAN

ROSE School / IUSS di Pavia

2nd fib Congress, Napoli, 5-8 June 2006

Overview

Introduction

Historic concrete

Problem statement

Concrete today

Innovative uses of concrete

Lessons learned

Decision considerations

Conclusions


Introduction

Story of construction technique (ex. Ostia: roman concrete > the vault)

Existing buildings: stories on construction concepts, materials, techniques

testimonials of innovation and spread

Requirements and decay > intervention need

„The stones of Athens would not tell us the story of the urban life in the city,wouldn‘t have all the written heritage remained.“

Lewis Mumford



Historic concrete


Concrete today


Concrete in time

Gap between use in antique and today

Natural stone for spatial structures in Gothic

19th century: reinforcement

RC in housing construction started to be employed during the Avantgarde

Some European capitals (RO, GR, PT):high-rise in central areas – luxury flats

Advanced construction technology was employed but not all possibilities researched



Problem statement

Condominium buildings

Higher amount

Less experiment on material use

1930s

Across Europe

Romania, Italy, Greece, Portugal

Compared to Germany and France



Innovative uses of concrete

Architecture office Kramm εt Strigl, Darmstadt, Germany

Housing construction since 1975

International recognition since 1983

Potential for lessons learned:housing construction with qualities above common buildings – like Modern Movement


Innovative use of concrete

Texture-modenature

Morphology and surface of glass and concrete:Pallaswiesen street, Darmstadt, DE

Role of concrete in the structure

Various materials, employment in concordance with the spatial feelingTechnology park and future centre, Herten, DE

Technology

Spatial cellshousing, Sauerland estate, Wiesbaden-Dotzheim, DE




Innovative use of concrete

Existing built substance

Bürgerparkviertel, Darmstadt, DE

Recycling procedure (TU Darmstadt)

Technical and economic value



Lessons learned

Recycling: testimony of the composition of the material (demolition and rebuild)

Spatial cells: frame serving as a shelf

Ottokar Uhl, Hollabrunn, Austria

Individual measures for units in condominium


Decision considerations

Decision – element in a management process

Decision – control options in operations

Management dimensions Processural > decision

Structural: organisational and operational structures

Personal: system

System: object | process Finding an optimal system for each group of actors

Regression technique > instruments for systematic decision


2 Project objectives

Development of a decentralised decision model Methodologic approach

modularisation of a collaborative decision model Non-measurable criteria, pairwise comparison

Decision making on two levels: actors and actors‘ criteria

Ways of solving contradictions between objectives of single actors in the retrofit implementation strategy Methodologic approach

development of a basis system to administrate modules on different levels of detail included in the urban strategical planning


Actors and groups of interests

Organisational – architecthistorical, building, element, material

Social – inhabitantexecution, acceptability, use, residential val.

Technical – engineervulnerability, structural performance,retrofit, strategy

Economic – investormanagement, availability (of technology,materials, funds), indicators


[Nr.]

Criterion [from] [to] [unit] [weight] Observations (on the units)

1 Reversibility 0 100 % 37,5 reversibility of the measure

2 Guidelines 1 5 points 37,5 for the complinance with maintenance guidelines

5 Facade 1 4 style points 9,0 for the architectural value of the façade

6 Interiors 1 4 spatiality points 9,0 for the architectural value of the space

7 Structural system 1 4 technology points 3,0 for the architectural value of the structure

8 Demolition 0 100 rebuild possibility 9,0 of the building following the original plans

9 Size change 0 50 cm 9,0 size change of a building element

10 Looks change 1 5 points 4,5 look change of a building element

11 Material change 1 2000 age (years) 9,0 of the construction material

13 Compatibility 0 100 % 4,5 collaboration with the existing construction material

14 Conservation 0 100 % 11,3 maintenance of the existing building material

15 Sustainability 1 500 years 2,3 lifetime of the building

16

AR

CH

ITE

CT

Maintenance 1 50 years 4,5 lifetime of the new construction material

17 Duration 1 100 weeks 4,5 of the measure

18 Noise 1 45 dB 1,5 noise during the measure

19 Move 1 100 weeks 12,0 duration of the relocation

20 Participation 0 15 decision steps 12,0 with possible participation of the inhabitants

21 Property form 1 5 points 7,2 lastingness of the inhabitance

22 Assurance 0 100 % coverage 33,6 earthquake damage through assurance

23 Own costs share 1 100 % 4,8 own costs/measure costs

24 Other advantages 1 5 points 14,4 for inhabitant advantages of the measure

25 During measures 0 200 spaces 9,0 usable during the measure

26 After measure 0 200 spaces 15,0 usable after the measure

27 After earthquake 0 200 spaces 6,0 usable after damaging in earthquake

29

US

ER

Value 1 20 points 30,0 for housing quality

33 Earthquake 1 12 EMS intensity 27,5 of the earthquake

34 Shape 8 10.10 scores 5,0 for seismic suitability of the conformation

35 Structure 0 8 scores 15,0 for seismic suitability of the structure

36 Material 1 6 scores 2,5 for seismic suitability of the construction material

37 Forces 0 1000 kN base shear 35,0 during the design earthquake

38 Remaining displacement 0 200 mm 105,0 at roof level after the earthquake

39 Maximal displacement 0 200 mm 105,0 at roof level during the earthquake

40 Strains -6 60 ‰ 105,0 in building elements during earthquake

41 Element replacement 0 300 number 25,0 replaced elements

42 New elements 0 300 number 7,5 new elements

43 Nonstruct>struct 0 300 number 10,0 nonstructural elements which become structural

44 Partial demolition 0 300 number 7,5 demolished elements

45 System completion 0 200 needed anchors 5,0 for a system completion measure

46 Strengthening/Stiffening 1 6 Sa_new/Sa_old 15,0 spectral acceleration new/old

47 Enhanced ductility 1 4 Sd_new/Sd_old 20,0 spectral displacement new/old

48

EN

GIN

EE

R

Reduced demand 1 6 damping actor 10,0 of the soil movement

49 Aggregate 1 44 nr. owners 8,0 of the building

50 Building site 0 24 hours available 12,0 for the work

51 Phases 1 44 simultaneous 12,0 conducted

52 Repeatability 1 200 nr. identical 8,0 retrofit measures

53 Material versus 10 40 price T€/app. 8,0 construction material price for measure at one housing unit

54 Technology v. 0 10 number 8,0 available technologies

55 Funding money 0 10 nr. programs 4,0 which could grant funding money

56 Replace space 0 5 eq. buildings 20,0 available for the relocation

57 Reparation/Rebuild 0 2 €/€ 5,0 costs/costs

58 Retrofit/Rebuild 0 0.5 €/€ 5,0 costs/costs

59 Reparation-save/Retrofit -5 5 €/€ 5,0 costs/costs

60

INV

ES

TO

R

Total costs/Rebuild-30% -0.3 2.2 €/€ 5,0 costs/costs


[Nr.]

Criterion [from] [to] [unit] [weight] Observations (on the units)

1 Reversibility 0 100 % 37,5 reversibility of the measure

2 Guidelines 1 5 points 37,5 for the complinance with maintenance guidelines

5 Facade 1 4 style points 9,0 for the architectural value of the façade

6 Interiors 1 4 spatiality points 9,0 for the architectural value of the space

7 Structural system 1 4 technology points 3,0 for the architectural value of the structure

8 Demolition 0 100 rebuild possibility 9,0 of the building following the original plans

9 Size change 0 50 cm 9,0 size change of a building element

10 Looks change 1 5 points 4,5 look change of a building element

11 Material change 1 2000 age (years) 9,0 of the construction material

13 Compatibility 0 100 % 4,5 collaboration with the existing construction material

14 Conservation 0 100 % 11,3 maintenance of the existing building material

15 Sustainability 1 500 years 2,3 lifetime of the building

16

AR

CH

ITE

CT

Maintenance 1 50 years 4,5 lifetime of the new construction material

17 Duration 1 100 weeks 4,5 of the measure

18 Noise 1 45 dB 1,5 noise during the measure

19 Move 1 100 weeks 12,0 duration of the relocation

20 Participation 0 15 decision steps 12,0 with possible participation of the inhabitants

21 Property form 1 5 points 7,2 lastingness of the inhabitance

22 Assurance 0 100 % coverage 33,6 earthquake damage through assurance

23 Own costs share 1 100 % 4,8 own costs/measure costs

24 Other advantages 1 5 points 14,4 for inhabitant advantages of the measure

25 During measures 0 200 spaces 9,0 usable during the measure

26 After measure 0 200 spaces 15,0 usable after the measure

27 After earthquake 0 200 spaces 6,0 usable after damaging in earthquake

29

US

ER

Value 1 20 points 30,0 for housing quality

33 Earthquake 1 12 EMS intensity 27,5 of the earthquake

34 Shape 8 10.10 scores 5,0 for seismic suitability of the conformation

35 Structure 0 8 scores 15,0 for seismic suitability of the structure

36 Material 1 6 scores 2,5 for seismic suitability of the construction material

37 Forces 0 1000 kN base shear 35,0 during the design earthquake

38 Remaining displacement 0 200 mm 105,0 at roof level after the earthquake

39 Maximal displacement 0 200 mm 105,0 at roof level during the earthquake

40 Strains -6 60 ‰ 105,0 in building elements during earthquake

41 Element replacement 0 300 number 25,0 replaced elements

42 New elements 0 300 number 7,5 new elements

43 Nonstruct>struct 0 300 number 10,0 nonstructural elements which become structural

44 Partial demolition 0 300 number 7,5 demolished elements

45 System completion 0 200 needed anchors 5,0 for a system completion measure

46 Strengthening/Stiffening 1 6 Sa_new/Sa_old 15,0 spectral acceleration new/old

47 Enhanced ductility 1 4 Sd_new/Sd_old 20,0 spectral displacement new/old

48

EN

GIN

EE

R

Reduced demand 1 6 damping actor 10,0 of the soil movement

49 Aggregate 1 44 nr. owners 8,0 of the building

50 Building site 0 24 hours available 12,0 for the work

51 Phases 1 44 simultaneous 12,0 conducted

52 Repeatability 1 200 nr. identical 8,0 retrofit measures

53 Material versus 10 40 price T€/app. 8,0 construction material price for measure at one housing unit

54 Technology v. 0 10 number 8,0 available technologies

55 Funding money 0 10 nr. programs 4,0 which could grant funding money

56 Replace space 0 5 eq. buildings 20,0 available for the relocation

57 Reparation/Rebuild 0 2 €/€ 5,0 costs/costs

58 Retrofit/Rebuild 0 0.5 €/€ 5,0 costs/costs

59 Reparation-save/Retrofit -5 5 €/€ 5,0 costs/costs

60

INV

ES

TO

R

Total costs/Rebuild-30% -0.3 2.2 €/€ 5,0 costs/costs


Building characteristics


Regression: goals of the architect

Induction

Data set: preservation, configuration, survey characteristics

Hypotheses:minimal intervention in the original structure

Deduction

Hypothesis: retaining the character

Hypotheses: element aspect

Statements: size, looks, material change


Regression: goals of the investor

Induction

Data set: four economic efficiency alternatives

Hypotheses:taking into account non-measurable criteria

Deduction

Hypothesis: benefit-cost investigation

Hypotheses: methods (transformation curves, ranking algorithms etc)

Statements: procedure to analyse the efficiency of pre- versus post-damage reparation


Retrofit alternative

First

eart

hquake

Se

cond

eart

hquake

Repara

tio

n (

€)

Retr

ofit

(€)

To

tal(

€)

Reb

uil

d (

€)

Repara

tion/

Rebuild

Retr

ofit/

Rebuild

Tota

l/ R

ebuild

Tota

l/ R

ebuild

-0,3

0

Repara

tio

n/

Retr

ofit

Retr

ofit/

Repara

tio

n

Diffe

rence t

o

unre

trofitt

ed

(€)

Repara

ttio

nsa-

vin

g/ R

etr

ofit

EQ A - 506950 0 506950 1561534 0,32 0,00 0,32 0,02 - 0 -

EQ A EQ A 526850 0 526850 1561534 0,33 0,00 0,33 0,04 - 0 -

EQ B - 422000 0 422000 1561534 0,27 0,00 0,27 -0,03 - 0 -

B0

EQ B EQ B 423050 0 423050 1561534 0,27 0,00 0,27 -0,03 - 0 -

EQ A - 544400 74785 619185 1561534 0,34 0,04 0,39 0,10 7 0,13 0 0

EQ A EQ A 595400 74785 670185 1561534 0,38 0,04 0,42 0,13 8 0,12 0 0

EQ B - 422000 74785 496785 1561534 0,27 0,04 0,31 0,02 6 0,17 0 0

B1

EQ B EQ B 479850 74785 554635 1561534 0,30 0,04 0,35 0,06 6 0,15 0 0

EQ A - 553050 67987 621037 1561534 0,35 0,04 0,39 0,10 8 0,12 46100 1

EQ A EQ A 605250 67987 673237 1561534 0,38 0,04 0,43 0,13 9 0,11 78400 1

EQ B - 477100 67987 545087 1561534 0,30 0,04 0,34 0,05 7 0,14 55100 -6

B2

EQ B EQ B 478800 67987 546787 1561534 0,30 0,04 0,35 0,05 7 0,14 55750 1

EQ A - 580950 67987 648937 1561534 0,37 0,04 0,41 0,12 9 0,11 74000 1

EQ A EQ A 606650 67987 674637 1561534 0,38 0,04 0,43 0,13 9 0,11 79800 1

EQ B - 473900 67987 541887 1561534 0,30 0,04 0,34 0,05 7 0,14 51900 1

B3

EQ B EQ B 476700 67987 544687 1561534 0,30 0,04 0,34 0,05 7 0,14 53650 1

EQ A - 455100 135973 591073 1561534 0,29 0,08 0,37 0,08 3 0,29 -51850 -0

EQ A EQ A 596400 135973 732373 1561534 0,38 0,08 0,46 0,17 4 0,22 69550 1

EQ B - 345850 135973 481823 1561534 0,22 0,08 0,30 0,01 3 0,39 -76150 -1

B4

EQ B EQ B 408900 135973 544873 1561534 0,26 0,08 0,34 0,05 3 0,33 -14150 -0

EQ A - 422950 176765 599715 1561534 0,27 0,11 0,38 0,08 2 0,41 -506950 -3

EQ A EQ A 586250 176765 763015 1561534 0,37 0,11 0,48 0,19 3 0,30 59400 0

EQ B - 442600 176765 619365 1561534 0,28 0,11 0,39 0,10 3 0,39 -422000 -2

B5

EQ B EQ B 476700 176765 653465 1561534 0,30 0,11 0,41 0,12 3 0,37 53650 0


Regression: goals of the engineer

Induction

Data set: report on building types

Hypotheses: problems and opportunities, retrofit provisions, damage patterns

Deduction

Hypothesis: retrofit elements

Hypotheses: technical and management preservation strategy

Statements: damage patterns


Regression: goals of the inhabitant

Induction

Data set: case studies of success stories in participative planning and construction

Hypotheses: participative planning approaches

Deduction

Hypothesis: innovation through pilot projects which will become better routine

Hypotheses: communication and education strategy

Statements: participation and communication instruments


Computer support

Costs-efficiency method: MS Excell Decision tree, Criterion weighting, Measurement space

Moderation between interests of actors

Difficulties Limited number of actors > 1st level: categories of actors

Criteria strengthening / agravating reciprocically

Finding units of measure

Pair-wise comparison Spread sheet

Multimedia

Typological choice: Hypertext and internet



Conclusions

Criteria for the selection of multi-storey RC structures of housing buildings from the 1st half of the XXth century to be preserved were formulated > ongoing research towards the development of a decision model, encompassing actors involved in the implementation of a retrofit measure.

Methodology: modularisation of a collaborative decision model taking into account non-measurable criteria

Pair-wise comparison more useful than decision tree

Thank you!

Acknowledgements:Marie Curie Intra-European Fellowship

MEIF-CT-2005-009765 contract of the European Commission

Insights from Dr. Rui Pinho, Prof. Rüdiger Kramm

Education

fib 2006