Dr Lourenço - Recomendaciones ICARSAH

ICOMOS methodology for conservation of cultural heritage buildings: Concepts, challenges, research and application to case studiesPaulo B. Loureno [email protected] www.civil.uminho.pt/masonry

Introduction

Institute for Sustainability and Innovation in Structural Engineering

3|ICOMOS methodology for conservation of cultural heritage buildings Paulo B. Loureno

Rehabilitacin y Conservacin Rehabilitacin y conservacin de edificios tiene cerca del 35% del mercado de la construccin en Europa, alcanzando ms de 50% en algunos pases Sociedades modernas creen que el patrimonio cultural construido debe durar para siempre. Este acto de cultura plantea grandes exigencias a los ingenieros, por que el deterioro es intrnseco a la vida El valor del mantenimiento del patrimonio construido puede ser de 1 a 2% del costo de la sustitucin. Para el funcionamiento se requiere otro tanto. Una estimacin en EE.UU. (Whitestone) proporcion un promedio de 6% al ao, el 35% de este valor de la operacin, 46% para el mantenimiento preventivo, reparacin y sustitucin, y el 19% para la recapitalizacin



Construcciones eternas

Efectos a largo plazo Los eventos extremos



Construcciones eternas



El patrimonio construido con valor cultural Recursos culturales que incluyen mritos tcnicos, artsticos y espirituales Hito cultural que proporciona identidad a las culturas, regiones y pueblos del mundo Autenticidad:

forma y diseo, materiales y sustancias, uso y funcin, tradiciones y tcnicas, ubicacin y el entorno, espritu y sentimiento, otros factores internos y externos.

no memory, no identity; no identity, no nation Ernest Gellner, philosopher and social anthropologist, LSE / Univ. Cambridge

we shape our buildings; thereafter they shape us Winston Churchill



Monumentos



8

Viviendas y edificios vernculos



Grupos de edificios, antiguos centros urbanos, textura urbana histrica



Obras destacadas de ingeniera desde la antigedad hasta el presente



patrimonio industrial(siglos 19 y 20)



patrimonio del siglo 20 con estructura de mampostera, acero y hormign



Nuevo patrimonio (el valor es independiente de la edad o de clasificacin)



The Role of the Engineer Conservation engineering is difficult and requires a different approach and skills from those employed in designing new construction:

Complexity (scatter of properties, lack of original design elements / Non-conforming execution, deficient structural connections, load transfer)

Different knowledge (materials, technologies, ) Lack of education in regular engineering / architecture courses Non-applicable codes Advanced structural analysis tools have justification



Risk Management, Technical Experts and Society Perception and communication Assessment and diagnosis Solutions, costs and implementation

How to solve the mathematical indeterminacy of huge consequences and low probabilities?

80.000 people/yearSince 1950, yearly costs increased more than 10x



Disaster risk management for cultural heritage Cultural heritage is invaluable, meaning that risk assessment is hardly applicable Lost cultural heritage cannot be reinstated by post-disaster measures How to achieve risk reduction and mitigation?

Studies show that the investment in mitigation saves four times the amount (Prevention pays) Multi-hazard risk analysis must provide a prioritization of needs The investment is large, meaning that an appropriate time frame must be considered Mitigation must be carried out on a comprehensive, community-wide, and long-term basis, leading to physically, socially, and economically resilient communities Disaster preparedness and post-disaster recovery (human suffering, economic losses and cultural losses)



What is an earthquake? An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves Waves result in shaking or rapid movements of the ground, possibly leading to loss of life and destruction of property If a building collapses, movable cultural heritage tend to be lost also

1755 Lisbon earthquake. A perfect disaster: tsunami with 10 m, fire for 5 days, 85% of the buildings destroyed, up to 90.000 deaths = 30% of population, Enlightenment Kant / Voltaire)



The seismic problem (I) Earthquakes hardly cause deaths, being the collapse of buildings the major cause of deaths and loss The scenarios for a large earthquake in Portugal (similar to 1755) predict about 10.000 deaths and a loss of 100 to 200% of the GDP

Carmo church, Lisbon Holy Mary church, Beja



The seismic problem (II)

1755, Lisbon 2009 and 2012, Itay2011, Spain

2012, Mxico



AcceptableKOBE Earthquake, 1995Earthquake magnitude was higher than 50% the design value: Extreme eventThe damage in the column is acceptable (even if not desired)



Unacceptable

Damage in this column is unacceptable



Acceptable Worst case scenario in masonry: embedded ring beam + unfilled vertical joints Light damage up to the design earthquake in Lisbon (rock) Ductile damage for 2.5x the design earthquake in Lisbon (rock)



Acceptable vs. Unacceptable

Cultural heritage buildings are usually rather vulnerable: (a) fragile materials; (b) heavy construction; (c) inadequate connections. Simple and moderate cost measures can make drastically change the situation



Example of churches in New Zealand (Earthquakes 2010-11) Red: unsafe building with access forbidden Yellow: safety compromised but urgent access allowed Green: no restrictions

red52%

yellow32% green16%

red38%yellow43%green19% red2%

yellow4%

green94%Stone Brick Timber

Conceptos:ICOMOS Recomendaciones



www.icomos.org

ICOMOS es una organizacin global no gubernamental dedicada a promover la aplicacin de teora, metodologa, y tcnicas cientficas para la conservacin de la arquitectura y el patrimonio arqueolgicoTrabaja con base en los principios consagrados en la carta internacional para la conservacin y restauracin de monumentos y sitios (Carta de Venecia) de 1964.

Fundada en 1965 como resultado de la adopcin internacional de la carta de Venecia en 1964Hoy en da ICOMOS ampara comits nacionales en 107 pases y mas de 20 comits cientficos

ICOMOS es el principal asesor par a la UNESCO con respecto a la proteccin y conservacin de monumentos y sitios.



ISCARSAHInternational Scientific Committee for Analysis andRestoration of Structures of Architectural Heritage(Comit cientfico internacional para el anlisis y restauracin de estructuras de patrimonio arquitectnico )

RECOMENDACIONES PARA EL anlisis, CONSERVACIN Y RESTAURACIN ESTRUCTURAL DE PATRIMONIO ARQUITECTONICO

PRINCIPIOS aprobados durante la 14 Asamblea General de ICOMOS en Victoria Falls, Zimbabue, Octubre 2003





Comprensin antiguaConservacin es justificada por la potencia de la intervencin Confianza ciega en los materiales y tecnologas modernosDesconfianza hacia los materiales antiguos o originales y los recursos de resistencia originales de los edificios El valor de estructura original / antigua y los principios estructurales no son reconocidosLa importancia de los estudios previos es no totalmente reconocidaSignificante experiencia negativa acumulada

Carta de Atenas (1931)Recomienda el uso de hormign y otros materiales modernos y tcnicas para propsitos de restauracin.Materiales adicionados y componentes deben ser escondidos para evitar alterar el aspecto histrico de las construcciones.



Comprensin modernaRespecto hacia la autenticidad de la estructura y los principios estructurales que gobiernan su respuestaLa conservacin debe yacer en el conocimiento y entendimiento de la naturaleza de la estructura y las causas reales de posibles daos o alteracionesIntervenciones mnimas y respetuosas (mnimo, no-intrusivo y reversible)Importancia de previos estudios (comprende aspectos histricos, materiales y estructurales)Los estudios previos y la intervencin son tareas multidisciplinarias que requieren de la cooperacin de historiadores, arquitectos, ingenieros, fsicos,.Carta de Venice (1964)Recomienda el uso de materiales tradicionales o histricos para la estabilizacin o restauracin. Sugiere el uso de materiales / tcnicas modernas para casos donde no es posible la estabilizacin o restauracin por medio de tcnicas tradicionales / histricas

Debe ser posible distinguir nuevos materiales o componentes de los originales.



Respeto por la autenticidad. Pero respetando los contestos culturales. No hay criterios fijosAceptabilidad de cambios de uso Requisitos de conservacin Requisitos de seguridadEnfoque multidisciplinar Entendimiento global de la estructura Metodologa Cientfica: anlisis, diagnostico, terapia y controlesNecesidad de entender a corto y largo plazo los efectos de cualquier accinUrgentes medidas de proteccin deben evitar alteraciones permanentes

ICOMOS Criterios Generales



Lo peculiar de las estructuras patrimoniales, con su compleja historia, requiere laorganizacin de estudios y anlisis en pasos que son similares a los usados en medicina.anlisis, diagnostico, terapia y control, correspondiendo respectivamente a lascondiciones estudiadas, identificacin de las causas de dao y deterioro, escogiendo lasmedidas correctoras y controlando la eficiencia de las intervenciones.



El valor de cada construccin histrica no es solo en la apariencia de sus elementos individuales, si no tambin en la integridad de todos sus componentes como un nico producto de la especifica tecnologa de construccin en su tiempo y lugar

As, la remocin de las estructuras internas conservando solo las fachadas no satisface el criterio de conservacin



When imperfections and alterations have become part of the history of the structure, they should be maintained providing they do not compromise the safety requirements.



Ninguna accin debe llevarse a cabo sin determinar el posible beneficio y dao al patrimonio arquitectnico.



El diagnostico es basa en informacin histrica as como en enfoques cualitativos y cuantitativosLos enfoques cualitativos estn basados en observacin directa del dao estructural y el deteriorodel material as como en investigaciones histricas y arqueolgicas, mientras que el enfoquecuantitativo requiere ensayos estructurales y de materiales, monitoreo y anlisis estructural.



Con frecuencia la aplicacin del mismo nivel de seguridad en el diseo de nuevas construccionesrequiere excesivas, si no imposibles, medidasEn estos casos otros mtodos, apropiadamente justificados,, pueden permitir diferentes enfoquesde seguridad. Por ejemplo, en la evaluacin cualitativa y cuantitativa podemos aceptar mejorar elnivel de seguridad (de acuerdo con el principio de mejora de seguridad) sin respetar enteramentelas prescripciones para nuevas construcciones, en base a controles analticos



La eleccin entre tecnicas tradicionales oinnovativas deben ser determinadas casopor caso, dando preferencia a aquellas quesean menos invasivas y mas compatiblescon el valor patrimonial, de acuerdo con lanecesidad de seguridad y durabilidad.



Siempre que sea posible, toda medida adoptada debe de serreversible, de modo que puedan ser removidas y reemplazadas conmedidas mas adecuadas si se adquieren nuevos conocimientos.Cuando no sea totalmente reversible, las intervenciones no debencomprometer intervenciones posteriores.



Mantenimiento adecuado puede limitar o posponer la necesidad de intervencin posterior



ICOMOS Metodologa (I)MONITOREOHISTORIA

Conclusiones en condiciones de construccin y adecuadas medidas correctoras

ANLISIS ESTRUCTURALINSPECCIN CONDICIN PRESENTE

EVIDENCIA EMPIRICA HIPOTESIS



DATA ACQUISITIONHistorical investigation (documents)Survey of the structure=documentField research and laboratory testingMonitoring

Historical investigation (documents)Survey of the structure=documentField research and laboratory testingMonitoring

STRUCTURAL BEHAVIOURStructural scheme: ModelMaterial characteristicsActions

Structural scheme: ModelMaterial characteristicsActions

DIAGNOSIS AND SAFETYHistorical analysisQualitative analysisQuantitative analysisExperimental analysis

Historical analysisQualitative analysisQuantitative analysisExperimental analysis

ExplanatoryReport

REMEDIAL MEASURESMasonryTimberIron and steelReinforced concrete

MasonryTimberIron and steelReinforced concrete

ExecutionDocuments

ICOMOS Metodologa (II)



SAFETY ASSESSMENT



1- LIMITED APPLICABILITY OF AVAILABLE CODES Codes prepared for the design of modern structures are often inappropriately applied to historic structures. They are based in calculation approaches which may fail to recognize the real structural behaviour and safety condition of ancient constructionsThe enforcement of seismic and geotechnical codes, can lead to drastic and often unnecessary measures that fail to take into account the real structural behaviour2- SUBJECTIVITY AND UNCERTAINTYAny assessment of safety is affected by two types of uncertaintiesThe uncertainty attached to data (actions, geometry, deformations, material properties), used in the research.The difficulty of representing real phenomena in a precise way with an adequate mathematical model (models provide only a limited representation of reality).The subjective aspects involved in the study and evaluation of a historic building may lead to conclusions of uncertain reliability

SAFETY EVALUATION DIFFICULTIES



Modern legal codes and professional codes of practice adopt a conservative approachinvolving the application of safety factors to take into account the various uncertainties.This is appropriate for new structures where safety can be increased with modest increasesin member size and cost.However, such an approach is not appropriate in historic structures where requirements toimprove the strength may lead to the loss of historic fabric or to changes in the originalconception of the structure.A more flexible and broader approach, where calculations are not the only source ofevaluation, needs to be adopted for historic structures to relate the remedial measuresmore clearly to the actual structural behaviour and to retain the principle of minimumintervention, with an adequate safety level-

It must be clear, therefore, that the practitioner responsible for the safety evaluation of an historic building should not be legally obliged to base his decisions solely on the results of calculations because, they can be unreliable and inappropriate.

LEGAL ISSUES



A more flexible and broader understanding, where calculations are not the onlysource of evaluation, needs to be adopted for historic structures, with aim at:The broader understanding consists of combining different approaches, eachgiving a separate contribution. Their combination will produce the bestpossible verdict based on the data available to us.

SAFETY EVALUATIONPROPOSED APPROACH



SAFETY EVALUATION: POSSIBLE APPROACHESHISTORICAL APROACHKnowing from history (Truescale experiment) QUALITATIVE APPROACH Inductive procedure (Comparing and extrapolating from other buildings)ANALYTICAL APPROACH Deductive procedure (Structural analysis)EXPERIMENTAL APPROACH (Experiments on individual components or the entire building)



Historical approach

Knowing from historyFull-scale / Real time experimentKnowing from the behaviour shown by the same structure, or similar ones, in the occasion of historical actions



Qualitative approach Inductive procedure (Comparing and extrapolating from other buildings)



Characterizing and validating typical failure modes for common buildings (allowing limit analysis by macroelements)



Analytical approach Deductive procedure (Structural analysis)

Modelling & analyzing a structure to obtain quantitativepredictions on the response subjected to different actions



Experimental approach (1)

Experiments on the entire building orindividual componentsExample: load tests in roof-slabs or vaults





Experimental approach (2)Step by step approach based on monitoringAcquire information during a step-by-step procedure of structural renovation. The behaviour is monitored at each stage (observational approach) and the acquired data used to provide the basis for any further action.Assess the maintenance of a sufficient level of safety in the long term

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20/03/20030:00 28/06/20030:00 06/10/20030:00 14/01/20040:00 23/04/20040:00 01/08/20040:00 09/11/20040:00 17/02/20050:000,00

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Serie2Serie3Serie1


63|ICOMOS methodology for conservation of cultural heritage buildings Paulo B. LourenoMETHODOLOGICAL CONSISTENCYDIAGNOSIS

SAFETY ASSESMENT

DESIGN OF REMEDIAL MEASURES



In short Scientific approach Combination of different sources and approaches Methodological consistency

Using similar approaches for diagnosis, safety evaluation and design of intervention Subjectivity is still possible Importance of personal judgment

Recognize the need for experts and the value of their personal judgment



Practice: Simple concepts vs. Difficult practice Basic aspects: Durability, compatibility, reversibility NO bargaining on safety Traditional AND novel intervention techniques are accepted Change of use IS allowed: A living cultural heritage Conservation engineering is an art, requiring specific education but some assets cannot survive without hard interventions

Challenges



Conflicting views? Reconstruct a new city? (I)

China



Conflicting views? Move buildings? (II)

China



Conflicting views? Birth-destruction-rebirth? (III)

Japan. Preserving technology / skills



Conflicting views? Replacing carved stone?

India. Preserving technology / skills



Conflicting views? Wrong doing with traditional materials?



Innovative materials in a non-controlled environment?



How much can we invest in knowledge?

Cost

Result

Knowledge



Conflicting views? Excess of regulations?



Conflicting views? Keep the faades?



Conflicting views? More than we can keep?



Urbanization and a dying rural landscape?



Conflicting views? Disasters?

1860

1970

2007

Rebuilding ofFrauenkirche in Dresden, Germany



What not to do (I)?

The need to understand materials, structural arrangements and construction techniques from existing buildings



What not to do (II)?

It is necessary to adopt adequate safety evaluation procedures (history, quantitative analysis, qualitative analysis, experimental analysis)

Recent research



The need of experimental knowledge



Survey and visual inspection



Non-destructive Testing

Sonic tomography-3.4 -3 -2.6 -2.2 -1.8 -1.4 -1 -0.6 -0.21

1.4

1.8

2.2

2.6

0 0.5 1 1.5 2

0.30.50.70.91.11.31.51.71.92.12.32.52.72.93.1

GPR testing

Strain gaugeMeasurements



Monitoring

Crack opening and tilting, Cathedral of Porto



Computer Simulation



Remedial Measures



Educacin (I)

Taylor y Francis,desde 2007(6 numeros/ao) Serie de conferencias: Structural Analysis of Historical Constructions(Anlisis estructural de construcciones histricas)

Bath, 2008250 participants

Padua, 2004350 participantsGuimares, 2001500 participants

New Delhi, 2006300 participants Wroclaw, 2012350 participants

Shanghai, 2010250 participants



Educacin (II) Erasmus Mundus MSc Curso en Anlisis Estructural de Monumentos y Construcciones Histricas: 200 estudiantes de 50 pases en 7 ediciones hasta ahora

Edicin n 8 en 2014/[email protected] para estudiantes:Entre 16.000 y 24.000 euro/ao.

Becas para profesores:1.200 euro/semana



Recent PhD theses at ISISE / Masonry & Timber (2011+)Earthquake engineering

Repair and strengthening

NDT and monitoringInnovative materials and construction technologies

Lifecycle analysis, safety and durability

Experimental characterization of the behavior of half-timber construction, Elisa Poletti (2013) Earth based grout injection materials, Rui Silva (2013) Durability analysis of bond between composite materials and masonry substrates, Bahman Ghiassi (2013) Avaliao do desempenho das envolventes dos edifciosface aco dos sismos, Manuel Paulo Pereira (2013) Metodologias inovadoras no clculo simples de estruturasde alvenaria simples e confinada, Rui Marques (2013) Seismic assessment of ancient masonry buildings: Shaking table tests and numerical analysis, Nuno Mendes (2013), with LNEC Anlise experimental de caldas base de cal para Injeode alvenaria antiga, Eduarda Luso (2012), with VTT, Finland Multiscale analysis of masonry structures using homogenization, Alberto Mauro (2012) cotutelle with Univ. Roma Tre A discrete element method for the study of masonry gravity dams, Eduardo Bretas (2012), with LNEC Safety assessment of ancient timber structures, Ricardo Brites (2011) Numerical analysis of FRP strengthened masonry structures, Claudio Maruccio (2011), Cotutelle with Univ. Rome Sapienza Assessment of the mechanical microstructure of masonry clay brick by nanoindentation, Konrad J. Krakowiak (2011), with MIT



Durability of bond between composites and masonry

Material testing

Temperature

Time(weeks)

(R.H. 90%)R.H.

0 2 4 6 83 different hygtothermal cycles + water immersion

NDT: IR thermography; DIC; Acoustic Emission Prediction models



Formulation and assessment of lime based grouts

Performance Mechanical characterization

Durability Wall repair and strengthening



Multiscale analysis of masonry structures

Homogeneization tools

Out of plane seismic testing Analytical models and design rules

Applications



Discrete element for masonry gravity dams

Draining andwaterprooofmembranes

Static analysis

Nailing andinjections

Dynamic analysis



Safety assessment of ancient timber structures

Biological deterioration

Detailed geometrical survey of ancient timber structures Meso-specimens and correlations

Applications



Analysis of FRP strengthened masonry structures

Multifan model, Braga and Liberatore (1990) Cyclic + FRP extension. Simulation of Pavia building

Constitutive bond model for interface, single lap tests and masonry arch tests



Microstructure of clay brick by nanoindentation

Material science paradigm

Identified phases and mechanical data

Better masonryHierarchical model for brick



Boxed buildings in the metropolitan area of Recife, Brazil

Inspection

13 collapses on masonry buildings (1 in 500, 40 years): 250.000 people at risk Opening up

Simulation



Dynamic identification and Wireless Sensor Networks

New prototype, with built in synchronization

Wireless monitoring systems Off the shelf solutions

Automatic system identification

Case studies



Applications (I)

Monastery of Jernimos Monastery of Salzedas Cathedral of Porto Convent of Tomar



Applications (II)Canterbury cathedral, UK

Qutb Minar, New Deli, India

Safi and Mazagan, Morocco

Pontifical defense, Italy

FamagustaCyprus

3.21

14.30

1.45

3.61

2.14

2.83

4.68

3.89

1.96

1.74

7.82

5.98

2.75

0.55

8.97

3.08

0.81

4.41

3.85

3.41

3.35

2.68

1.33

14.29

1.32

8.14

2.58

6.62

3.13

3.37

3 .55

3.50

F1

2.23

0.35

6.83

2.86

1.28

1.24

1.41

2.77

1.19

1.19

2.581 .45

1.44

2.84

1.371.42

2.76

6.251.46

8.39

3.34

3.34

3.34

3.54

3.54

3.45

3 .55

1.25

3.45

3.34

2.01

2.010.54

2.43

1.44

0.44

T

T

*Deteriorao daspedras do arco

Fendas na separapanos de alvenaria

Fendas na chave dasabbadas

Mashad, Iran





Cathedral of Porto (I)

South Tower

North Tower



Cathedral of Porto (II)

ferior F3F4

C2TS2

TH

C1 F2

D

F1

TS1

Monitoring

Advanced structural analysis

Non-destructive testing



Cathedral of Porto (III)



Iglesia de San Cristbal, Cusco (I)

Origin1560 (18th century)



Iglesia de San Cristbal, Cusco (II)



Iglesia de San Cristbal, Cusco (III)



Iglesia de San Cristbal, Cusco (IV)



Monastery of Salzedas



Typical Cistercian Abbey. Considerable size in plan, 75.0 101.0 m2. Origin from the XII century.Cloister from the 17th century. Classical model with columns and closed upper gallery. Ribbed crossed vaults in the first floor and cannon vaults in the second floor.



Context Portugal 1834: the new political system, of liberal and constitutional origin, decides the extinction of religious Orders, confiscates their properties and sells them in auction. Monastery of Salzedas was left abandoned with demolitions, stealing, ruined or in the verge of collapse parts. Nature slowly taking care of the site. No restoration. Unfinished works. A harmonious disorder where everything evokes time. A time of multiple pasts felt in each single part of the building: the scars, the clear vestiges from other eras, the unexpected shapes of the incomplete and the empty. General actions: (a) Cleaning removal of biological infestation, and removal and selection of debris with the archaeological assistance, from which a set of stabilized and stored elements and fragments resulted; (b) Consolidation of the parts considered at risk; (c) Protection stopping, even if with temporary system, infiltration of rainwater; (d) Access creation reinstate, using permanent, or temporary structures, the horizontal and vertical communications lost; install scaffolding for inspection; (e) Geometrical Survey of the entire compound; (f) Inventory and Conservation for movable heritage.



Stop tourist visits Protect against rainwater infiltration Urgent measures in the cloister Moderate funding Decision: To preserve the ruin (or keep the aesthetics of time). Present

intervention would be as much effective, as it would remain invisible

Further action after a global strategy for the monument was decided

Step 1

Step 2

Step 3

Actions in the main cloister



Situation found

DE

A

BC

Replacement of the barrel vault of theWest wingDismantling and reassembly of the wall between the small and the large cloisters

A ChurchB SacristyC Chapter roomD Main cloisterE Small cloister

Damage survey



Main cracks (I)

First floor crossed vaults Second floor barrel vaults



Main cracks (II)

South wing at the 2nd level

South-West corner at the 2nd level

West wing at the 1st level

South-West corner at the 1st level



Limited cracksin the walls

Internal wall of the West wing

External wall of East wing External wall of South wing



Separation between vaults and walls

Out of plumbness of walls (2nd level). Resulted in vertical displacements in vaults extrados up to 0.10 m

Large movements in the cloisters internal walls



Other damage

Crushing / shearing ofbrackets Deterioration of bricks

Stone deterioration Biological colonization and moisture stains



Stone deterioration mapping and study on salts

Highlights of structural survey, NDT and numerical analysis



Aspect of column foundations

EmbankmentOrganic soil

Alluvial soil with stonesAlluvial stones with pebble

Granular soil with clayLarge stones

Soil foundation exhibits moderate resistance and very large heterogeneity for depths between 1.0 and 1.8 m

Aspect of wall foundations

Foundation inspection pits



Tests on walls and vaults (I)

The vaults are built with clay brick masonry with 0.22m thickness and infill (soil in 1st level and lime concrete in the 2nd level)The walls are built with large granite stones, mostly with clay mortared jointsInternal longitudinal cracks or voids were not foundLow strength and high porosity bricks (compressive strength 5 N/mm2)



Tests on walls and vaults (II)

Samples for the uniaxial compression tests Eb = 7.3 GPa fb = 5.2 MPaEm = 8.6 GPa fm = 3.8 MPa



Structural analysis (Linear Elastic)

Deformation of the structure Maximum principal stresses Minimal principal stresses The large horizontal displacements observed in the structure can only be explained by a geometrical and physical non-linear analysis The 3D model served also for validation of a simplified 2D model (only of the 2nd floor) The structure presents original conceptual deficiencies (insufficient buttressing in internal walls)



Non-linear analysis

0.00.20.40.60.81.01.2

0.0 1.0 2.0 3.0 4.0Deslocamento (cm)

Factor

de car

ga

HorizontalVertical

Damage in the barrel vault

Damage in all the entire structure

Displacement (cm)

Load fa

ctor

Relation between the load factor and the displacements exhibited by the structure (zero safety level)Foundations and long term behaviour of the structure are mostly responsible for observed damageStrengthening is needed

Execution details



Remedial measuresReforo com CFRP

Inclinao do pavimento = 1.0%

Inclinao do pavimento = 2.5%Lajeado em pedra a repor

Adjustable propping Partial removal of infill (2 wings in 2nd level) Partial removal of infill (2 wings in 1st level) Elevation of 2 wings (1 in each level). 10 cm Pulling of one corner. 12.5 cm Local protheses in stone brackets / ribs Repointing and injection of cracks andjoints in vaults Stainless steel ties Water tightening of 2nd level Repointing joints in the external walls Closing of openings



Reforo com CFRP



Reforo com CFRP



Reforo com CFRP




132|ICOMOS methodology for conservation of cultural heritage buildings Paulo B. Loureno2nd Level


133|ICOMOS methodology for conservation of cultural heritage buildings Paulo B. LourenoPiso 2UNI

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134|ICOMOS methodology for conservation of cultural heritage buildings Paulo B. Loureno1st Level

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Elevation of vaults (I)



Elevation of vaults (II)



Dismantling (III).



Protection



Adjusting colors



Completed South wall

Before

After



Stainless steel AISI 316L



Drilling



2nd Level



1st Level



Floor Level

2nd Level

1st Level



Escuela de Teologia en Braga


147|ICOMOS methodology for conservation of cultural heritage buildings Paulo B. LourenoDescripcin Edificio de gran tamao con dimensiones en (cuerpo principal 110 x15 m2) y 5 plantas (Planta Baja + 4 niveles)

Losas y muros internos de concreto reforzado y mampostera en granito en los muros exteriores Uno de los primeros edificios en concreto reforzado en Braga (1930s) 5o planta con piso de concreto no utilizado como tico 3o y 4o planta originalmente como dormitorios para estudiantes. Losas soportadas por vigas transversales, soportadas en paredes externas, muros rellenos con concreto reforzado (plantas 2/5)

Seccin transversal Blueprint and body and consideration

Vigas principalesVigas secundriasMuros de concretoreforzado



Descriccin (I)

Fachada principal Fachada trasera

Corredor tipico (nivel 2, 3 y 4) Muros y vigas no alineados



Descriccin (II)

Hall en la planta baja (luz de 13 m)

tico irregularidades



Inspeccin Geometrica

Planta Seccin transversal Nivel 1 (Hall) es un espacio de luz libre Muros transversales con un espaciamiento de 2.60 m Muros transversales no simtricos Muros externos de mampostera con espesor variable en altura: 0.30-0.60 m. Vigas principales con 0.25 x 0.50 m2 (niveles 3 y 4) y 0.30 x 0.60 m2 (nivel 2)

13.30



Caracterizacin de materiales

Corte

Acero (aberturas de inspeccin y deteccin de refuerzo)

Propiedades del concreto obtenidas a travs de extraccin de muestras, uso del martillo Schmidt y pruebas ultrasnicasEn promedio para las vigas un valor de 25 N/mm2 y de 12 N/mm2 paralos muros Viga principal con un As, lower de 31 (nivel 3 y 4) y 41+ 41 (nivel 2).(1% y 3%) Losas con 0.12 m de espesor, con 3/[email protected] (Asl) y 3/[email protected] (Ast).(0.5% y 0.25%) Muros interiores con 0.06 m de espesor, con 3/[email protected] (Asv) y 5/[email protected] (Ash). (0.25% y 0.08%) Varillas de acero templado y no corrugadas


152|ICOMOS methodology for conservation of cultural heritage buildings Paulo B. LourenoValoracin de la seguridad de las losas

Nuevo uso: Los niveles superiores (3 y 4) son utilizados como archivo, mientras que los nivelesinferiores (1 y 2) permanecen como escuela. Se han previsto cargas muy altas (11 a 15kN/m2). Las losas estaban bien para el uso previo. Pero para el nuevo uso es necesario elreforzamiento (Mitad del refuerzo requerido). Un conjunto de HEB 100 puestastransversalmente a la celda, soportadas en una L 80x80 y un nuevo tablero de madera serianecesario (700 euro por celda).

Propuesta original:3 armarios con 2.40 mNueva propuesta:2.80 m + 0.80 m + 2.80 m (nivel 4)3.60 m + 0.80 m + 3.60 m (nivel 3)4.00 m + 0.80 m + 4.00 m (nivel 2)Nuevo piso con soportes cerca a los muros No intervencin



Valoracin de la seguridad del edificio completo (I)

Esfuerzos principales de tensin

Modelo en tres dimensiones Malla deformada por G+Q

Esfuerzos principales de compresin



Valoracin de la seguridad del edificio completo(II)

Momentos deflexin

Esfuerzos principales en los muros externos: tensin y compresin

Nive 2

Nive 3

Nivel 4

MSd, mx = 56.5 kN.m

MSd, mx = 44.5 kN.m



Valoracin de la seguridad del edificio completo(III)

MomentosDe flexin

Reemplazo del modelo 3D al modelo equivalente en 2D 3D 2D

Nivel 2

Nivel 3

Nivel 4

MSd, mx = 47.3 kN.m

MSd, mx = 48.3 kN.m

Error:Mupper: -16%Mlowe: +9%



Valoracin de la seguridad del edificio completo (IV)

Separacin progresiva entre las vigas del nivel 2 y los muros

Combinacin de cargas 1.35G+1.35Q y desplazamientos en la mitad de la luz (Level 2)



Valoracin de la seguridad del edificio completo (V)

Posibilidad de un refuerzo localizado (no aconcejable)

Agrietamiento Posible reforzamiento local(no recomendado y no adoptado)



Reforzamiento (I) Dos soluciones fueron consideradas: (a) Reforzamiento de la losa del primernivel con una parrilla de vigas de acero y nuevas columnas; (b)reforzamiento con suspensin y transferencia de cargas parciales de lasvigas transversales a los muros externos. El diseo preliminar conduca a una diferencia de costo de 1:2. La solucinde menor costo fue usada, incluso teniendo menos implicacionesarquitectnicas y menos restricciones durante el tiempo de ejecucin El reforzamiento fue llevado a cabo con nuevas cerchas de acero, barras deapoyo de suspensin de 40mm hasta el nivel 2. un sistema paralelo doblees usado para amarrar las cerchas de madera original y los muros y vigasde concreto. Gatos hidrulicos fueron usados para garantizar latransferencia de carga.



Reforzamiento (I)

Tipica cercha de acero a nivel de piso



(a) Soportes de las cerchas de acero; (b) diagonales amarrando los muros transversales;(c) Gatos para la transferencia del nuevo sistema; (d) suporte de las nuevas vigas de acero

Conclusiones


162|ICOMOS methodology for conservation of cultural heritage buildings Paulo B. LourenoConclusiones La conservacin es un complejo y emocionante campo. Herramientas y conocimientos especficos para esta disciplina estn disponibles Una metodologa cientfica y solida est disponible, sin embargo la experiencia y el criterio personal continan siento un asunto importante Dos casos de estudio han sido presentados en mampostera y edificios de concreto reforzado. Mampostera es muy durable, en cuanto concreto reforzado es ms susceptible a la corrosin. Se entiende que la fbrica se debe mantener se posible en ambos los casos y las intervenciones deben ser mnimas. La construccin en mampostera necesitaba reparacin debido a envejecimiento, aislamiento cimentaciones y alteraciones, con perdida de capacidad. La construccin en concreto reforzado necesitaba refuerzo debido a un aumento de carga y deficiencias originales Se subray la necesidad de: (a) un claro entendimiento del comportamiento de estructuras complejas; (b) una adecuada valoracin de la necesidad de reforzamiento estructural; (c) una anlisis de costo de diferentes posibles soluciones en la fase inicial de diseo.

ICOMOS methodology for conservation of cultural heritage buildings: Concepts, challenges, research and application to case studiesPaulo B. Loureno [email protected] www.civil.uminho.pt/masonry