Smaragda Antoniou. Historic Industrial Arched R.C. Structures: Investigation and Modelling

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1 Smaragda Antoniou Historic Industrial Arched R.C. Structures: Investigation and Modelling Italy 2009

2 DECLARATION Name: Smaragda Antoniou Title of the Msc Dissertation: Supervisor(s): Historic Industrial Arched R.C. Structures: Investigation and Modelling Francesca da Porto Year: 2009 I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. I hereby declare that the MSc Consortium responsible for the Advanced Masters in Structural Analysis of Monuments and Historical Constructions is allowed to store and make available electronically the present MSc Dissertation. University: University of Padova Date: July 22, 2009 Signature: i

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4 ACKNOWLEDGEMENTS First of all I would like to express my gratefulness to SAHC Consortium, for giving me the opportunity to partecipate in a very interesting international postgraduate programme, and for providing me a Consortium Scholarship. I would also like to express gratitude to all the Professors that have taught me during the coursework in Barcelona, and especially the coursework coordinator, Professor Pere Roca. I would also like to thank my supervisor, Francesca da Porto, Assistant Professor at the Faculty of Engineering, Department of Structural and Transportation Engineering, for her cooperation and her guidance to perform this thesis. Moreover, I am very grateful to Elena Stievanin, PhD student at the Faculty of Engineering, Department of Structural and Transportation Engineering, for her valuable help and collaboration, as well as Michelle Secco and Matteo Parisatto, PhD students at the University of Padova, Department of Geoscience, for their contribution to my study. iii

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6 ABSTRACT The objective of the thesis is to present an investigation on historic arched reinforced concrete structures. The first part of the thesis consists of the study of the historical evolution of concrete as a construction material and its possible degradation mechanisms. Furthermore, there is an investigation on two historical reinforced concrete structures, located at the industrial zone of Marghera, close to the city of Venice. The investigation on one of the structures will include non-destructive and minor-destructive testing in order to estimate the quality and mechanical properties of concrete, and also the location of the reinforcement. For the other structure, information about the materials are available. The first building (complex Città della Musica ) consists of two bodies of different height, forming a plan of an L shape. Each part is formed by a series of frames with an almost arched shape. One representative arched structures of each body has been sellected and modelled by means of the finite element analysis software Straus 7, in order to carry out a structural analysis and a response spectrum analysis. The second building (complex Città del Cinema ) consists of a series of reinforced concrete arches that form the frame of the building. The building consists of only one part and forms a rectangular plan. From this building, a representative arch has been modelled using the finite element analysis software Straus 7 as well, and a structural analysis and a response spectrum analysis has been performed. In all the three cases the analysis was based on combination of actions according to contemporary european codes. The last part of the thesis includes comments on the condition of the buildings, based on the results of the investigations and the analyses. v

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8 ASTRATTO Lo scopo di questa tesi postlaurea è di rappresentare una ricerca storica sugli archi realizzati in cemento armato. La prima parte di questo lavoro è costituita dallo studio dell evoluzione storica del cemento armato come materiale di costruzione ed i possibili meccanismi del suo degrado.. Di seguito si fa una ricerca su due costruzioni storiche realizzate in cemento armato che si trovano nella zona industriale di Marghera vicino alla città di Venezia. La ricerca su una delle due costruzioni comprende delle prove non distruttive e semi distrutttive in modo da stimare la qualità e le proprietà meccaniche del cemento armato, lo spessore del copriferro e la posizione del ferro. Per quanto riguarda l altro edificio sono disponibili le informazioni sui materiali di costruzione impiegati. Il primo edificio (complesso Città della Musica ) è composto da due parti con altezza diversa che sono unite tra di loro realizzando una pianta di forma ad L. Ogni sua parte è composta di telai in fila i quali hanno all incirca una forma ad arco. Un arco rappresentativo di ognuna delle suddette parti è stato scelto e riprodotto in modello mediante un codice di calcolo ad elementi finiti Straus 7 in modo da realizzare la sua analisi statica e l analisi dello spettro di risposta. Il secondo edificio (complesso Città del Cinema ) è composto da una serie di archi di cemento armato i quali ne costituiscono la struttura portante. L edificio consta di un corpo unico ed ha una pianta a forma rettangolare. Un arco rappresentativo di questo edificio è stato analizzato staticamente, si è analizzato inoltre il suo spettro di risposta, mediante il codice di calcolo ad elementi finiti Straus 7. Per questi tre casi l analisi statica è stata eseguita utilizzando le direttive delle vigenti normative europee. L ultima parte di questa tesi postlaurea contiene osservazioni sullo stato degli edifici che si basano sui risultati delle ricerche e delle analisi effettuate sulle strutture. vii

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10 ΠΕΡΙΛΗΨΗ Ο σκοπός της πτυχιακής αυτής εργασίας µε θέµα «Ιστορικοί Βιοµηχανικοί Τοξωτοί Φορείς από Ο.Σ.: Έρευνα και Προσοµοίωση» ( Historic Industrial Arched R.C. Structures: Investigation and Modelling ) είναι να παρουσιαστεί µια έρευνα πάνω σε ιστορικούς τοξωτούς φορείς από οπλισµένο σκυρόδεµα. Το πρώτο τµήµα της εργασίας αποτελείται από τη µελέτη της ιστορικής εξέλιξης του σκυροδέµατος ως δοµικό υλικό και τους πιθανούς µηχανισµούς υποβάθµισής του. Στη συνέχεια, γίνεται µια έρευνα σε δύο ιστορικές κατασκευές από οπλισµένο σκυρόδεµα, οι οποίες βρίσκονται στη βιοµηχανική περιοχή της Μαργκέρα, κοντά στην πόλη της Βενετίας. Η έρευνα στη µία από τις δύο κατασκευές περιλαµβάνει µη-καταστρεπτικές και ηµι-καταστρεπτικές δοκιµές ώστε να εκτιµηθεί η ποιότητα και οι µηχανικές ιδιότητες του σκυροδέµατος, το πάχος της επικάλυψης και η θέση του οπλισµού. Όσον αφορά την άλλη κατασκευή, πληροφορίες σχετικά µε τα υλικά είναι διαθέσιµες. Το πρώτο κτίριο (συγκρότηµα Città della Musica ) αποτελείται από δύο τµήµατα διαφορετικού ύψους, ενωµένα µεταξύ τους, σχηµατίζοντας µία κάτοψη σχήµατος L. Το κάθε τµήµα του σχηµατίζεται από πλαίσια σε σειρά, τα οποία έχουν ένα περίπου τοξωτό σχήµα. Ένας αντιπροσωπευτικός τοξωτός φορέας από κάθε τµήµα έχει επιλεχθεί και προσοµοιωθεί µέσω του προγράµµατος ηλεκτρονικού υπολογιστή Straus, ώστε να αναλυθεί στατικά. Το δεύτερο κτίριο (συγκρότηµα Città del Cinema ) αποτελείται από µία σειρά τόξων από οπλισµένο σκυρόδεµα, τα οποία σχηµατίζουν το σκελετό του. Το κτίριο αποτελείται από ένα τµήµα και σχηµατίζει µία ορθογωνική κάτοψη. Από το κτίριο αυτό ένα αντιπροσωπευτικό τόξο έχει επίσης προσοµοιωθεί µέσω του προγράµµατος ηλεκτρονικού υπολογιστή Straus, και έχει γίνει η στατική του ανάλυση. Για τις τρεις αυτές περιπτώσεις η ανάλυση έγινε βάσει συνδυασµού δράσεων σύµφωνα µε σύγχρονους κανονισµούς. Το τελευταίο µέρος της πτυχιακής εργασίας περιλαµβάνει σχόλια για την κατάσταση των κτιρίων τα οποία βασίζονται στα αποτελέσµατα των ερευνών και των αναλύσεων. ix

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12 TABLE OF CONTENTS PG. 1. INTRODUCTION HISTORICAL EVOLUTION OF CONCRETE AS A BUILDING MATERIAL DETERIORATION MECHANISMS OF CONCRETE Corrosion of the reinforcement Alkali-aggregate reaction Alkali-silica reaction Alkali-silicate reaction Alkali-carbonate reaction Other alkali-aggregate reactions Creep of concrete Chemical attack on concrete Leaching of concrete Fire on concrete Effect of repeated loading on concrete Concrete structures subjected to overloading Deterioration caused by cyclic freezing and thawing VISUAL INSPECTION ON STRUCTURES Introduction Tools and equipment of visual inspection General procedure of visual inspection Applications of visual inspection TESTING OF CONCRETE IN STRUCTURES Introduction Available test methods Non-destructive testing of concrete...21 xi

13 Introduction Overall review of available NDT methods for concrete structures Mechanical methods Ultrasonic methods Electrical methods Magnetic methods Electromagnetic methods Infrared thermographic methods Acoustic emission methods Radioactive methods Penetrability methods Minor-destructive testing of concrete In-situ investigations Concrete coring Core location and size Drilling for mechanical tests Drilling for petrographic analysis Laboratory tests Compression testing DESCRIPTION OF THE INDUSTRIAL AREA OF PORTO MARGHERA CASE STUDY I: COMPLEX CITTÀ DELLA MUSICA Investigation campaign Introduction Measurement of water absorption, density and mechanical resistance Measure of carbon dioxide penetration Numerical modelling Introduction Arched structure of principal body...46 xii

14 Loading conditions Combination of actions Results of the analysis Verification of capacity Verification of logitudinal reinforcement Verification of shear resistance Arched structure of secondary body Loading conditions Combination of actions Results of the analysis Verification of capacity Verification of logitudinal reinforcement Verification of shear resistance CASE STUDY II: COMPLEX CITTÀ DEL CINEMA In-situ investigation Introduction Visual inspection of decay Pachometer application Sclerometer application Extraction of cores Laboratory compression tests Phenolphthalein application Numerical modelling of a representative arched structure Introduction Loading conditions Combination of actions Results of the analysis Verification of capacity xiii

15 Verification of logitudinal reinforcement Verification of shear resistance CONCLUSIONS ANNEX xiv

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