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EARTHQUAKE ENGINEERING IN EUROPE
GEOTECHNICAL, GEOLOGICAL AND EARTHQUAKEENGINEERING
Volume 17
Series Editor
Atilla Ansal, Kandilli Observatory and Earthquake Research Institute,Bogaziçi University, Istanbul, Turkey
Editorial Advisory Board
Julian Bommer, Imperial College London, U.K.Jonathan D. Bray, University of California, Berkeley, U.S.A.
Kyriazis Pitilakis, Aristotle University of Thessaloniki, GreeceSusumu Yasuda, Tokyo Denki University, Japan
For further volumes:http://www.springer.com/series/6011
Earthquake Engineeringin Europe
edited by
MIHAIL GAREVSKIInstitute of Earthquake Engineering and Engineering Seismology (IZIIS),
Skopje, R. Macedonia
ATILLA ANSALKandilli Observatory and Earthquake Research Institute,
Bogaziçi University, Istanbul, Turkey
123
EditorsMihail GarevskiInstitute of EarthquakeEngineering & Engineering Seismology
(IZIIS)[email protected]
Atilla AnsalKandilli Observatory and Earthquake
Research InstituteBogaziçi UniversityCengelkoy 34688Istanbul, [email protected]
ISSN 1573-6059ISBN 978-90-481-9543-5 e-ISBN 978-90-481-9544-2DOI 10.1007/978-90-481-9544-2Springer Dordrecht Heidelberg London New York
Library of Congress Control Number: 2010932608
© Springer Science+Business Media B.V. 2010No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or byany means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without writtenpermission from the Publisher, with the exception of any material supplied specifically for the purposeof being entered and executed on a computer system, for exclusive use by the purchaser of the work.
Printed on acid-free paper
Springer is part of Springer Science+Business Media (www.springer.com)
Preface
The need for integrated books on earthquake engineering and management isincreasing, particularly having in mind the rising trend of damage and loss ofhuman lives due to earthquakes. The increase of the seismic risk is not becauseof the increase of the number of occurred earthquakes since their frequency doesnot change statistically, but it is rather due to the growing population in earthquakeprone areas.
The book contains the invited papers to be presented at the 14th EuropeanConference on Earthquake Engineering (14ECEE) to be held in Ohrid,R. Macedonia, during 30th August – 3rd September, 2010. This event takes placeevery 4 years and represents the most important forum for exchange of resultsfrom the latest investigations carried out in the field of earthquake engineeringbetween two conferences. The present book containing the papers of the keynoteand theme lecturers is published in addition to the Book of Abstracts and the DVDdisc containing all the papers submitted to the Conference.
The unique character of this book is that the titles of the chapters are selected toenable a complete insight into the state-of-the-art in the field of earthquake engineer-ing. The papers related to engineering seismology and seismic risk management, inaddition to the papers on earthquake engineering in this book, add much to its valuesince they are concerned with problems related to high intensity earthquakes.
The book will be of a high benefit for the participants of the Conference andother scientists because the authors have presented much of the latest research donein this field. It can also be a useful tool for the engineers and students since theauthors were allowed to present their investigations in much detail (up to 25 pages).All the illustrations (photos and figures) that are in full colour contribute to bettervisualization of the issues involved in this book.
The contributors to the book are among distinguished scientists from Europe.Submissions of renowned researchers from the USA are also included. The bookstarts with the contribution entitled “Seismic Engineering of Monuments” byT. Tassios, who is awarded to deliver the First Prof. Nicholas AmbraseysDistinguished Lecture. This presentation is followed by six sections on the followingtopics:
v
vi Preface
Engineering Seismology;Geotechnical Earthquake Engineering;Seismic Performance of Buildings;Earthquake Resistant Engineering Structures;New Techniques and Technologies;Managing Risk in Seismic Regions.
Each of these sections starts with the contributions of the keynote speakersfollowed by those of the theme lecturers.
The first section begins with the presentation of A. Ansal et al. dealing withseismic microzoning and comparison of different microzoning maps elaborated onthe basis of different parameters. The possibility of application of ground motionprediction equations (GMPEs) developed for a single region to other regions isconsidered in the subsequent presentation (J. Stewart).
The second section starts with soil response to earthquake ground motion.Reference is given to seismic response of structures including soil-structure interac-tion by linear and nonlinear analysis (A. Pecker and C.T. Chatzigogos). The secondcontribution is given by P. Bard et al. and it considers non-destructive techniquesas the ambient vibration measurements for obtaining soil site amplifications. Thissection ends with the contribution of Cubrinvski et al. that investigates the decreaseof liquefaction resistance with increased quantity of non-plastic fines.
The subsequent section referring to the behaviour of buildings under earthquakeeffect contains six chapters. All these chapters deal with themes that are very muchof a current interest. F. Naeim analyses the behaviour (performance based seismicdesign) of tall buildings considering the growing popularity of construction of suchbuildings in seismically prone regions. The need for introducing nonlinear analysisof structures in engineering practice is pointed out (N. Aydinoglu and G. Onem).This part of the book also contains review of techniques used for retrofitting andstrengthening of historic buildings (C. Oliveira and A. Costa). Further in this section,G. M. Calvi summarizes the historical background of implementation and improve-ment of engineering regulations contributing to safe seismic construction. In hispaper, A. Kappos provides examples of different procedures for design of build-ings with different number of storeys. At the end of the section, J. Wallace givesrecommendations for performance based design of tall core wall structures.
In the fourth section of the book dedicated to earthquake resistance of engineer-ing structures, P. Pinto and P. Franchin consider problems and methods used inanalysis and design of bridges. Further in this section, in the chapter on develop-ment of health monitoring of structures (E. Safak et al.), consideration is given to anumber of techniques for detection of damage to structures.
In the penultimate section, A. Pinto describes large scale pseudo-dynamic andhybrid (substructure) nonlinear tests. The next paper in this section written by R.Severn presents the great contribution of seismic shaking table tests of models tothe progress of earthquake engineering in the period 1900–1980. This part of thebook ends with a paper on manufacturing, testing and installation of low-cost rubberbearings (M. Garevski).
Preface vii
The last section of the book considers the possibilities for reduction and mit-igation of earthquake consequences. S. Briceno presents the goals of the HyogoFramework for Action. It is suggested that successful seismic risk reduction isonly possible provided that risk management is incorporated in the planning pol-icy of each country located in a seismically active region. This part also containsexamples of necessary measures taken in the aftermath of the Abruzzi earthquake(M. Dolce). In the paper by C. Modena et al., special attention is paid to historicbuildings damaged by the L’Aquila earthquake. The next paper (M. Erdik et al.)refers to almost real time damage assessment. The methodology and the softwarefor rapid earthquake loss assessment is considered. The book ends with the con-tribution of H. Shah et al. that considers the possibility of renovation of dwellingsdamaged by earthquakes through development of a safety economic net in the formof micro insurance.
The editors wish to extend their gratitude to all the authors of the included papersfor their cooperation in the creation of this book that provides a valuable contribu-tion to the common goal of the earthquake engineering community, i.e., reductionof loss of human lives and damage to property due to earthquakes.
Skopje, Republic of Macedonia Mihail GarevskiIstanbul, Turkey Atilla Ansal
Contents
1 Seismic Engineering of Monuments . . . . . . . . . . . . . . . . . . 1T.P. Tassios
Part I Engineering Seismology
2 Microzonation for Earthquake Scenarios . . . . . . . . . . . . . . . 45Atilla Ansal, Gökçe Tönük, and Aslı Kurtulus
3 Analysis of Regional Ground Motion Variationsfor Engineering Application . . . . . . . . . . . . . . . . . . . . . . 67Jonathan P. Stewart
Part II Geotechnical Earthquake Engineering
4 Non Linear Soil Structure Interaction: Impacton the Seismic Response of Structures . . . . . . . . . . . . . . . . 79Alain Pecker and Charisis T. Chatzigogos
5 From Non-invasive Site Characterization to SiteAmplification: Recent Advances in the Use of AmbientVibration Measurements . . . . . . . . . . . . . . . . . . . . . . . . 105P.-Y. Bard, H. Cadet, B. Endrun, M. Hobiger, F. Renalier,N. Theodulidis, M. Ohrnberger, D. Fäh, F. Sabetta,P. Teves-Costa, A.-M. Duval, C. Cornou, B. Guillier,M.Wathelet, A. Savvaidis, A. Köhler, J. Burjanek, V. Poggi,G. Gassner-Stamm, H.B. Havenith, S. Hailemikael,J. Almeida, I. Rodrigues, I. Veludo, C. Lacave, S. Thomassin,and M. Kristekova
6 Effects of Non-plastic Fines on Liquefaction Resistanceof Sandy Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125Misko Cubrinovski, Sean Rees, and Elisabeth Bowman
Part III Seismic Performance of Buildings
7 Performance Based Seismic Design of Tall Buildings . . . . . . . . 147Farzad Naeim
ix
x Contents
8 Evaluation of Analysis Procedures for Seismic Assessmentand Retrofit Design . . . . . . . . . . . . . . . . . . . . . . . . . . . 171M. Nuray Aydınoglu and Göktürk Önem
9 Reflections on the Rehabilitation and the Retrofitof Historical Constructions . . . . . . . . . . . . . . . . . . . . . . 199Carlos Sousa Oliveira and Aníbal Costa
10 Engineers Understanding of Earthquakes Demandand Structures Response . . . . . . . . . . . . . . . . . . . . . . . . 223Gian Michele Calvi
11 Current Trends in the Seismic Design and Assessment of Buildings 249Andreas J. Kappos
12 Performance-Based Design of Tall Reinforced ConcreteCore Wall Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . 279John W. Wallace
Part IV Earthquake Resistant Engineering Structures
13 Open Issues in the Seismic Design and Assessment of Bridges . . . 311Paolo E. Pinto and Paolo Franchin
14 Recent Developments on Structural Health Monitoring andData Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331Erdal Safak, Eser Çaktı, and Yavuz Kaya
Part V New Techniques and Technologies
15 Large Scale Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . 359Artur Pinto
16 The Contribution of Shaking Tables to Early Developmentsin Earthquake Engineering . . . . . . . . . . . . . . . . . . . . . . 383R.T. Severn
17 Development, Production and Implementation of Low CostRubber Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411Mihail Garevski
Part VI Managing Risk in Seismic Regions
18 Investing Today for a Safer Future: How the HyogoFramework for Action can Contribute to Reducing DeathsDuring Earthquakes . . . . . . . . . . . . . . . . . . . . . . . . . . 441Sálvano Briceño
19 Emergency and Post-emergency Managementof the Abruzzi Earthquake . . . . . . . . . . . . . . . . . . . . . . . 463Mauro Dolce
Contents xi
20 L’Aquila 6th April 2009 Earthquake: Emergency andPost-emergency Activities on Cultural Heritage Buildings . . . . . 495Claudio Modena, Filippo Casarin, Francesca da Porto, andMarco Munari
21 Rapid Earthquake Loss Assessment After Damaging Earthquakes 523Mustafa Erdik, Karin Sesetyan, M. Betul Demircioglu,Ufuk Hancilar, and Can Zulfikar
22 Catastrophe Micro-Insurance for Those at the Bottomof the Pyramid: Bridging the Last Mile . . . . . . . . . . . . . . . . 549Haresh C. Shah
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563
Contributors
J. Almeida Lisbon Fundaçao da Faculdade Ciencias da Universidade de Lisboa,IDL, 1749-016 Lisboa, Portugal, [email protected]
Atilla Ansal Kandilli Observatory and Earthquake Research Institute, BogaziçiUniversity, Çengelköy, Istanbul, Turkey, [email protected]
M. Nuray Aydınoglu Kandilli Observatory and Earthquake Research Institute,Bogaziçi University, 34684 Istanbul, Turkey, [email protected]
P.-Y. Bard LGIT, Maison des Geosciences, Joseph Fourier University, 38041Grenoble Cedex 9, France, [email protected]
Elisabeth Bowman Department of Civil and Natural Resources Engineering,University of Canterbury, Christchurch 0050 8140, New Zealand,[email protected]
Sálvano Briceño UNISDR, Palais des Nations, Geneva, Switzerland,[email protected]
J. Burjanek Swiss Seismological Service, ETH Zürich, 8092 Zürich, Switzerland,[email protected]
H. Cadet Institute of Engineering Seismology and Earthquake Engineering(ITSAK), 55102 Thessaloniki, Greece, [email protected]
Eser Çaktı Kandilli Observatory and Earthquake Research Institute, Bogaz iciUniversity, 38684 Istanbul, Turkey, [email protected]
Gian Michele Calvi Department of Structural Mechanics, University of Pavia,27100 Pavia, Italy, [email protected]
Filippo Casarin Department of Structural and Transportation Engineering,University of Padova, 35131 Padova, Italy, [email protected]
Charisis T. Chatzigogos Géodynamique et Structure, 92220 Bagneux, France,[email protected]
C. Cornou LGIT, Maison des Geosciences, Joseph Fourier University, 38041Grenoble Cedex 9, France, [email protected]
xiii
xiv Contributors
Aníbal Costa Department of Civil Engineering Aveiro, Universidadede Aveiro, Aveiro, Portugal, [email protected]
Misko Cubrinovski Department of Civil and Natural Resources Engineering,University of Canterbury, Christchurch 8140, New Zealand,[email protected]
M. Betul Demircioglu Kandilli Observatory and Earthquake Research Institute,Bogazici University, 34684 Istanbul, Turkey, [email protected]
Mauro Dolce Seismic Risk Office, Italian Department of Civil Protection, 00189Rome, Italy, [email protected]
A.-M. Duval CETE Méditerranée, 06359 Nice Cedex 4, France,[email protected]
B. Endrun Institute of Earth and Environmental Sciences, University of Potsdam,14476 Potsdam OT Golm, Germany, [email protected]
Mustafa Erdik Kandilli Observatory and Earthquake Research Institute, BogaziciUniversity, 34684 Istanbul, Turkey, [email protected]
D. Fäh Swiss Seismological Service, ETH Zürich, 8092 Zürich, Switzerland,[email protected]
Paolo Franchin Department of Structural and Geotechnical Engineering,University of Roma “La Sapienza”, 00197 Rome, Italy,[email protected]
Mihail Garevski Institute of Earthquake Engineering and EngineeringSeismology, Ss. Cyril and Methodius University, 1000 Skopje, Republicof Macedonia, [email protected]
G. Gassner-Stamm Swiss Seismological Service, ETH Zürich, 8092 Zürich,Switzerland, [email protected]
B. Guillier LGIT, Maison des Geosciences, Joseph Fourier University, 38041Grenoble Cedex 9, France, [email protected]
S. Hailemikael Ufficio Valutazione del Rischio Sismico, Dipartimento dellaProtezione Civile, 00189 Roma, Italy, [email protected]
Ufuk Hancilar Kandilli Observatory and Earthquake Research Institute, BogaziciUniversity, 34684 Istanbul, Turkey, [email protected]
H.B. Havenith Swiss Seismological Service, ETH Zürich, 8092 Zürich,Switzerland
M. Hobiger LGIT, Maison des Geosciences, Joseph Fourier University, 38041Grenoble Cedex 9, France, [email protected]
Andreas J. Kappos Laboratory of Concrete and Masonry Structures, Departmentof Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124,Greece, [email protected]
Contributors xv
Yavuz Kaya Kandilli Observatory and Earthquake Research Institute, BogaziciUniversity, 38684 Istanbul, Turkey, [email protected]
A. Köhler Institute of Earth and Environmental Sciences, University of Potsdam,14476 Potsdam OT Golm, Germany, [email protected]
M. Kristekova Geophysical Institute, Academy of Sciences, 845 28 Bratislava,Slovak Republic, [email protected]
Aslı Kurtulus Kandilli Observatory and Earthquake Research Institute BogaziçiUniversity, Çengelköy, Istanbul, Turkey, [email protected]
C. Lacave Résonance S.A., CH-1227 Carouge-Genève, Switzerland,[email protected]
Claudio Modena Department of Structural and Transportation Engineering,University of Padova, 35131 Padova, Italy, [email protected]
Marco Munari Department of Structural and Transportation Engineering,University of Padova, 35121 Padova, Italy, [email protected]
Farzad Naeim Earthquake Engineering Research Institute, Oakland, CA, USA;John A. Martin & Associates, Inc., Los Angeles, CA, USA,[email protected]
M. Ohrnberger Institute of Earth and Environmental Sciences, Universityof Potsdam, 14476 Potsdam OT Golm, Germany, [email protected]
Carlos Sousa Oliveira Department of Civil Engineering and Architecture/ICISTLisbon, Instituto Superior Técnico, Lisbon, Portugal, [email protected]
Göktürk Önem Kandilli Observatory and Earthquake Research Institute,Bogaziçi University, 34684 Istanbul, Turkey, [email protected]
Alain Pecker Géodynamique et Structure, 92220 Bagneux, France,[email protected]
Artur Pinto ELSA, IPSC, Joint Research Centre, Ispra, 21020 VA, Italy,[email protected]
Paolo E. Pinto Department of Structural and Geotechnical Engineering,University of Roma “La Sapienza”, 00197 Rome, Italy, [email protected]
V. Poggi Swiss Seismological Service, ETH Zürich, 8092 Zürich, Switzerland
Francesca da Porto Department of Structural and Transportation Engineering,University of Padova, 35131 Padova, Italy, [email protected]
Sean Rees Department of Civil and Natural Resources Engineering, Universityof Canterbury, Christchurch 8140, New Zealand, [email protected]
F. Renalier LGIT, Maison des Geosciences, Joseph Fourier University, 38041Grenoble Cedex 9, France, [email protected]
xvi Contributors
I. Rodrigues Lisbon Fundaçao da Faculdade Ciencias da Universidade de Lisboa,IDL, 1749-016 Lisboa, Portugal, [email protected]
F. Sabetta Ufficio Valutazione del Rischio Sismico, Dipartimento della ProtezioneCivile, 00189 Roma, Italy, [email protected]
Erdal Safak Kandilli Observatory and Earthquake Research Institute, BogaziçiUniversity, 38684 Istanbul, Turkey, [email protected]
A. Savvaidis Institute of Engineering Seismology and Earthquake Engineering(ITSAK), 55102 Thessaloniki, Greece, [email protected]
Karin Sesetyan Kandilli Observatory and Earthquake Research Institute,Bogazici University, 34684 Istanbul, Turkey, [email protected]
R.T. Severn Earthquake Engineering Research Centre, University of Bristol,Bristol, UK, [email protected]
Haresh C. Shah Department of Civil and Environmental Engineering, StanfordUniversity, Stanford, CA 94305-4020, USA; RMS, Inc., Newark, CA 94560, USA;WSSI, Newark, CA, USA, [email protected]
Jonathan P. Stewart University of California, Los Angeles, CA, USA,[email protected]
T.P. Tassios National Technical University of Athens, Athens, [email protected]
P. Teves-Costa Lisbon Fundaçao da Faculdade Ciencias da Universidade deLisboa, IDL, 1749-016 Lisboa, Portugal, [email protected]
N. Theodulidis Institute of Engineering Seismology and Earthquake Engineering(ITSAK), 55102 Thessaloniki, Greece, [email protected]
S. Thomassin Résonance S.A., CH-1227 Carouge-Genève, Switzerland,[email protected]
Gökçe Tönük Kandilli Observatory and Earthquake Research Institute, BogaziçiUniversity, Çengelköy, Istanbul, Turkey, [email protected]
I. Veludo Lisbon Fundaçao da Faculdade Ciencias da Universidade de Lisboa,IDL, 1749-016 Lisboa, Portugal, [email protected]
John W. Wallace NEES@UCLA Laboratory, Department of Civil andEnvironmental Engineering, University of California, Los Angeles, CA90095-1593, USA, [email protected]
M. Wathelet LGIT, Maison des Geosciences, Joseph Fourier University, 38041Grenoble Cedex 9, France, [email protected]
Can Zulfikar Kandilli Observatory and Earthquake Research Institute, BogaziciUniversity, 34684 Istanbul, Turkey, [email protected]
Chapter 1Seismic Engineering of Monuments
T.P. Tassios
Abstract In this contribution the particularities of the seismic re-design ofMonuments are discussed, related to their structural repair or strengthening. AMonument, besides its possible practical use and its economical value, requires alot of other Values to be respected during its aseismic retrofitting, such as its aes-thetic Form, the authenticity of its materials, etc. In order to respect these Values,the Engineer tends to minimize structural intervention – thus, violating social val-ues such as the preservation of the Monument for future generations, the protectionof human lifes, etc. An optimization is needed, and this contribution attempts todescribe the necessary procedures to this end. On the other hand, emphasis is givento the particular difficulties in the determination of the resistance of masonry, aswell as in the selection of suitable methods of Analysis, taking into account thespecificity of each Monument. To this end, the contribution includes comments onmonumentic Values and performance requirements, and emphasizes the need foran institutionalization of levels of importance, levels of visitability and of accept-able damage-levels for all monuments of each Country, as a basic input of aseismicdesign of monuments. Subsequently, criteria are given for the selection of methodsof Analysis, and detailed comments are included about experimental investigationsand strengths’ determination. The final optimization procedure is then described,regarding the optimum seismic resistance level to be lent to a specific Monument.
1.1 The Significance of the Subject
It is broadly accepted that in seismicly prone regions, the seismic behaviour ofMonuments is of a paramount importance.
First, because of the cultural need to maintain and transfer these Monuments tofuture generations (Figs. 1.1 and 1.2). To this end, more or less drastic structural
T.P. Tassios (B)National Technical University of Athens, Athens, Greecee-mail: [email protected]
1M. Garevski, A. Ansal (eds.), Earthquake Engineering in Europe, Geotechnical,Geological, and Earthquake Engineering 17, DOI 10.1007/978-90-481-9544-2_1,C© Springer Science+Business Media B.V. 2010
2 T.P. Tassios
Fig. 1.1 The Parthenon, Acropolis of Athens
Fig. 1.2 Historical muslim temple underneath Acropolis of Athens
1 Seismic Engineering of Monuments 3
interventions (repair or strengthening) are implemented,1 with the lowest possibleconsequences on the “monumentic” values.
Second, our interest for the seismic resistance of Monuments is also encouragedby the legal obligation to protect human life (of the neighbours, curators, visitors oreven inhabitants of the monumental building).
However, the preparation of design documents regarding structural interventionsof Monuments is frequently facing several difficulties, not encountered in the caseof non-monumental buildings, such as:
• Additional uncertainties related to the available resistances of building compo-nents
• Particularities in selecting the appropriate method of Analysis, suitable (i) to agiven typology of the Monument and (ii) to the level of resistance uncertainties
• Difficulties in selecting
– An appropriate design value of seismic action, such that the respectivenecessary intervention will not jeopardise the monumentic values of theMonument, and
– Appropriate Techniques with an optimum level of reversibility/re-interventionality.
Because of these difficulties, the approval of submitted design-documents is fre-quently an occasion for controversial discussions between Engineers, on the onehand, and Architects and Archeologists, on the other.
1.2 Structural Interventions and the Conflict of Values
These controversies are but a reflection of the contrarieties between the following“Principles” (Values and Requirements) related to the structural interventions inMonuments:
(a) Monumentic2 Values
a1: Form (aesthetic value).a2: History (symbolic value).a3: Preservation of ancient building-Techniques and Materials (technical
value).
1In this respect, specialists do not anymore share the view that “since a Monument has withstoodprevious earthquakes, it will continue to resist any future seismic action”.2This neologism is a very useful term to express concepts and things related to Monuments, avoid-ing however the possible confusion with the secondary meanings of the term “monumental” (i.e.impressively large, outstanding, astounding).
4 T.P. Tassios
(b) Social Values
b1: Preservation of the cultural Memory of a Monument (integrity, survival).b2: Adequate safety against normal actions and Earthquakes (value of human
life).b3: Modern use of Monuments.b4. Cost-reduction of the structural intervention.
(c) Performance – requirements regarding the structural intervention (InterventionValues)
c1: Reversibility level and or re-interventionality levelc2: Durabilityc3: Technical reliability
Every intervention aiming at a structural repair or strengthening of a Monumententails some inevitable harm to several of these values and performance-requirements, depending on the actual condition of the Monument and the availabletechnologies. It suffices perhaps to give a few typical examples:
– In order to preserve the Form and the integrity of a seismicly vulnerableMonument, a rather costly strengthening solution is adopted, consisting in (i)extensive grouting of masonry walls and (ii) change of the old (completelydecayed) roof (Fig. 1.3). Thus, the following “principles” were violated: a3, b4and c1.
– A second typical example may be the case of a monumental building made ofprecious historical materials to be completely preserved; the solution here wasto offer seismic safety by means of external buttresses (Fig. 1.4). The violated“principles” here were: a1 and a2.
– In a third case, to avoid any harm to monumentic Values of a delicate Monument,some rather simple and provisional structural interventions were decided, offeringa seismic resistance lower than the one required for modern important build-ings. In this case, a remarkable violation of the social value of “human lifesafety” (principle b2) was accepted, together with a transgression of the durabilityrequirement (c2).
Apparently, in all these cases, Authorities have sought an optimization3 ofPrinciples, and came to their final decision, knowingly of the partial violation ofthe “set of Principles”. In this respect, it is reminded that such an optimization can-not be reached by means of just “scientific” judgments: The values entering thegame are of different nature; they are not amenable to identical “units” – they arenot quantitatively comparable between each other!
That is why, in the field of structural interventions of Monuments, only man-agerial (almost political) decisions are feasible; weighing factors for each of these
3See Sections 1.9 and 1.10.
1 Seismic Engineering of Monuments 5
Fig. 1.3 Presentation of the historical ceiling of the church of St. Irene, Athens
Principles may be (directly or indirectly) discussed within an interdisciplinarygroup, and a final “optimal” decision be made.
Such an optimization process, directly affects some important technical issuesrelated to the seismic (re)design of Monuments: The design value of seismic actionshas to be decided taking (also) into account its eventual consequences on monu-mentic values, too, as well as on costs and technical performances. Thus, a sort of
6 T.P. Tassios
Fig. 1.4 The Hosios Loukas monastery 11th cent. Church (Greece), strengthened by means ofexternal buttresses (11th cent)
“negotiation”4 of design seismic actions is initiated: Disproportionately high design-values, serve the “human life” and the “integrity” principles, but they may jeopardisesome monumentic values and performance requirements. Therefore, a better overallintervention (an “optimal” solution) may be sought, based on possibly lower design-values of seismic actions, i.e. on higher exceedance probability. The same holds truefor the selected intervention schemes and technologies; they should also be finallydecided following a similar optimization process.
In order to facilitate such a decision making process, further rationalization ofdata is needed regarding the “Importance” of a given Monument, as well as its“Visitability” level.
4After all, design seismic actions regarding modern buildings are also negociated: The sociallyacceptable “probability of exceedance” of seismic actions imposed by actual Codes, depends onseveral variables, such as the actual economical level of the Country and the social importance ofthe building, i.e. on non-scientific data. The difference in Monuments is that the case of such a“negociation” is taking place within a broader multiparametric space, including many additionalValues and Requirements.
1 Seismic Engineering of Monuments 7
1.3 Importance, Visitability and Acceptable Damage-Levels
• Seismic actions’ values for the re-design of Monuments may also depend onacceptable damage-levels, which in their turn will be decided on the basis of theimportance of each Monument. That is why in many Countries, a categorisationof Monuments is available to designers, as follow:
– I1: Monuments of universal importance (Fig. 1.5)– I2: Monuments of national importance (Fig. 1.6)– I3: Monuments of local interest (Fig. 1.7)
• Another useful tool towards a rationalisation of decision making regarding struc-tural interventions, is the categorization of the occupancy of Monuments: Higheroccupancy means higher concern for human lives against earthquakes, and there-fore higher seismic actions’ design values. That is why engineering decisionswould be facilitated if a “visitability” categorisation of Monuments would bemade available, such as in the following list:
V1: Almost continuous presence of public or frequent presence of large groups
– Inhabited buildings in historical city centres– Monuments used as Museums– Monuments continuously used for worshipping
Fig. 1.5 The Hagia Sophia church in Istanbul, a monument of universal importance
8 T.P. Tassios
Fig. 1.6 The Arta bridge (15th cent) in Greece, a monument of national importance
Fig. 1.7 A “neoclassical” building in Athens (19th cent), a monument of local importance
1 Seismic Engineering of Monuments 9
V2: Occasional habitation or intermittent presence of small groups
– Monuments visited only under specific conditions– Remote and rarely visited Monuments
V3: Entrance allowed only to Service-Personnel. Visitors stand only outside theMonument.
• Combining the aforementioned Importance-levels and Visitability-levels, it ispossible to decide acceptable Damage-levels (“I” for negligible damage, up to IVfor serious damage, see Figs. 1.8, 1.9 and 1.10), under the re-design earthquake.Such a possible matrice is given here below (indicatively though):
Prevailing valuesAcceptable damage-levels (I to IV)under the re-design seismic actions Human life and monument’s integrity
Visitability V1 V2 V3
Formandhistory
Importance level I1 I II II II2 I II III III3 II III IV III
To this end, a systematic description of each damage-level is needed, sep-arately for traditional masonry buildings, arched structures or domes, andgraeco–roman monuments.
Fig. 1.8 Local diagonal cracks only: level II damage (Anavatos, Chios Island, Greece)
10 T.P. Tassios
Fig. 1.9 Compressive localfailures; level III damage(Anavatos, Chios Island,Greece)
It is believed that such an approach may substantially facilitate rational decisionmaking, related to structural interventions of Monuments against seismic actions.
1.4 Historical and Experimental Documentation,and Uncertainty Levels
1.4.1 Introduction
(a) Long experience shows that the structural design document regarding seis-mic strengthening of a Monument is an integral part of the broader study ofthe Monument; history and architecture of the Monument are indispensableprerequisites for the Structural Design, in order to account for all initial andconsecutive construction phases, previous repairs etc.
(b) Description of existing and or repaired damages (visible or possibly hiddenones), together with their in-time evolution; monitoring, be it a short term one,may be helpful.
1 Seismic Engineering of Monuments 11
Fig. 1.10 Local collapses;level IV damage (Anavatos,Chios Island, Greece)
(c) Systematic description of the in-situ materials, including their interconnec-tions – especially in the case of three leaf masonry walls. Connections ofperpendicular walls are thoroughly investigated.
(d) Results of experimental investigations regarding:
– geometrical data,– internal structure,– in-situ strength of materials,– structural properties of masonry walls,– dynamic response of building elements,– subterranean data,
as well as results of possible previous monitoring installations (displacements,settlements, internal forces, humidity, groundwater level, cracks’ opening,seismic accelerations, environmental data etc).
(e) Description of the structural system(f) Description of the soil and the foundation
1.4.2 Experimental Documentation
It is worth to inventorise first the categories of structurally useful data needed (thusmaking clear the scope of the experimental investigation), together with the partic-ular methods used to this end. Thus, a better understanding of function, importance
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and interdependence of these methods will be achieved. Laboratory methods andmonitoring are separately considered. Physical-chemical aspects are not examinedin this contribution.
Instrumental In-Situ Methods
(a) Geometrical data
• Visual description of structural parts; Laser scanning, Photogrammetry• Cracks
– Opening: Lenses, Photogrammetry, Strain gauges– Depth: Ultrasonic tests– Length: Measuring tape, Photogrammetry
• Displacements: Phtogrammetry, Inclinometers, Penduli
(b) Internal structure (Van de Steen et al., 1997; Binda et al.; 1998, 2003;Maierhofer et al., 2004; Wenzel and Kahle, 1993; Silman and Ennis, 1993;Thomasen and Sears, 1993; Binda and Saisi, 2001)
• Hidden voids or discontinuities: Endoscopy, Thermography, Radar, Sonictomography, Radiography
• Internal building details: Endoscopy (see also BIPS-method (Fig. 1.11)),Radar, Sonic tomography (Fig. 1.12).
• Hidden metals: Magnetometry, Radiography, Thermography, Radar
(c) In-situ strength of constitutive materials
• Stones: Rebound, Ultrasonic, Scratch width• Infill material: Sonic cross-hole• Mortars: Scratch width, Penetration test (Felicelti and Gattesco, 1998)• Timber: Penetrometer (Giuriani and Gubana, 1991)• Metals: Hardness test in-situ• Bonding strength: Mortar pullout test
(d) Structural properties of masonry
Acting compressive stressesCompression resistanceShear resistance
⎫⎬
⎭
In situ jack-tests (Binda et al. 1997, 2003)
(e) Effectiveness of Grouting: Sonic tomography, Endoscopy, Radar (Berra et al.,1991; Côte et al., 2004)
(f) Dynamic response of building elements
• Microtremors• Cable-release tests• Vibrodyne
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Fig. 1.11 Borehole ImageProcessing Systems (BIPS).The entire cylindrical surfaceof the boring is developed andexamined in the case of anendoscopy in the Tower ofPisa, near the deficient area ofthe helicoidal stairs (Macchiand Ghelfi, 2006)
(g) Subterranean data
• Seismic tomography• Ground radar
Laboratory Methods
(a) Core testing: Compression, Tension(b) Tests of irregular mortar-fragments(c) Testing on replicas: re-made masonry, subassemblages
Monitoring (in-Time)
(a) Displacements: Horizontal deformetric wires, Penduli, Laser measurements,Inclinometers
(b) Settlements: Leveling systems, Inclinometers
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Fig. 1.12 Sonic tomography along a wall of Dafni Monastery, (Greece), after grouting (Côte et al.,2007)
(c) Internal forces: Inserted dynamometers, Flat jacks(d) Humidity within masonry: Neutron probes, GPR, Thermograhy(e) Ground-water level: Water pressure borings(f) Cracks: Opening evolution and control(g) Seismic actions: Seismometers, Accelerometers(h) Environmental data: Temperature, Solar radiation, Wind.
For our purposes, it is good to know that such a rather impressive weaponry ismade available to us, in order to “see” the interior of the (black and silent) “box”of the structural elements of a Monument. It has however to be reminded that thisextensive inventory of experimental methods cannot be used in every case; not onlybecause of economical and accessibility difficulties, but mainly because of the mul-tiple limitations of applicability of each of these methods. Thus, an optimum use ofthese methods should be made, on a case-by-case basis, depending on:
– the importance of the Monument and its financing– the inadequacies of available historical data– the level of roughly estimated vulnerability of the Monument– the technical characteristics of the Monument– the time schedules, etc.
1 Seismic Engineering of Monuments 15
A lot of the aforementioned methods are well known to the Engineers; severalbooks and papers describe them in detail (see i.a. Tassios and Mamillan, 1985).
1.4.3 Uncertainty Levels
The combination of historical and experimental documentation data, is an indis-pensable basis for the structural re-design of a Monument, since the structure of aMonument is a rather silent black-box; every effort is justified to make this box totalk. However, a lot of uncertainties will remain. And our scientific duty is to beconscious of these uncertainties and of the way they may affect Analysis (hiddendiscontinuities, behaviour of connections etc), as well as Resistance determination(hidden voids, weathered or inhomogenious materials, etc). Otherwise, our compu-tational efforts may not be able to correctly evaluate the seismic resistance of theMonument and to appropriately design its best strengthening.
Long experience shows that for each primary structural member of theMonument, an appropriate level of reliability of documentation should be assigned,referring separately to basic data, such as:
– Dimensions, eveness and verticality– Composition transversally to the element (e.g. three leaf masonry?)– Connections with neighbouring elements.– Strengths of constitutive materials, etc.
For each of these categories of data, a “Documentation-Reliability level” shouldbe assessed in each particular case, (indicatively: “missing”, “inadequate”, “suffi-cient”). An important contribution to this end is offered in Section 1.4.2 (p. 35) of theItalian Guides, 2007, [D2]. In accordance with this characterization, Analysis andResistance evaluation methodologies will be more accurately selected (see Sections1.5 and 1.6).
1.5 Structural Analysis
1.5.1 Introduction
(a) The analytical procedure may include the following analysis, independently orin combination:
– Analysis of the entire monument (occasionally without some possiblysecondary elements)
– Analysis of some selected structural sub-assemblages, in order to identifythe most critical weaknesses of the monument.
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(b) The structural system has to be clearly identified; the rich data included in theDocumentation of the Monument are very helpful in this respect.
(c) Selection criteria of the method of seismic Analysis, appropriate for theMonument under consideration:
• For more important and or complicated Monuments, more sophisticatedmethods appear more justified.
• For each of the main typological categories of stone monuments, someparticular methods may be more appropriate.
• Depending on acceptable damage-level (Section 1.3), a respective method ofAnalysis may be used. Indicatively:
– In case of targeted negligible damage under the design earthquake, onlylinear Analysis is applicable.
– In case of extensive accepted damages, a non-linear static Analysis seemsto be more suitable.
• The available level of “Reliability of the Documentation” (Section 1.4)should also be taken into account when selecting the appropriate methodof Analysis. Low RD-levels are not compatible with highly sophisticatedmethods.
(d) A warning may be useful, related to the use of data found by means of dynamicexperimental excitations. These data, applicable for structural identification,should not be used for spectral response calculations; in fact, eigen frequen-cies determined by means of dynamic excitations, are considerably higher thanreal frequencies under actual displacement and damage conditions.
1.5.2 General Criteria for the Selection of the Methods of Analysis
(a) Depending on monument’s morphology:
– Depending on the extent and the complexity of the monument, non-linearanalysis of all parts by means of three-dimensional models is not alwayspossible.
– Significant non-regularities necessitate linear dynamic analysis (indepen-dently, or in combination with static non-linear analysis)
– Slender parts also necessitate the use of linear dynamic method.
(b) The final selection of an analytical method will be based on its capacityto “reproduce” (by computation) previous damage patterns, roughly though(Fig. 1.13).