The 21st century has brought with it myriad innovative construction techniques and structural systems; however reinforced masonry systems have gone virtually unchanged over the last decades. The innovative Surface-Reinforced Concrete Masonry Unit (SRCMU) system makes use of Near-Surface Mounted reinforcement to form a structurally efficient system. Preliminary analysis of this system shows the potential for improved moment resistance when compared to conventional masonry construction. There is also evidence for a potential decrease in embodied and operating energy for finished structures using the SRCMU system. Experimental work indicates similar axial compressive behaviour of the SRCMU when compared to conventional concrete masonry systems. Pull-out and flexural tests performed on reinforced SRCMU specimens indicate it is possible to achieve a good bond between the SRCMU system and the reinforcing bars; up to 60kN of pull out force was developed in 590mm of bonded length, and flexural specimens developed up to 20kNm/m of moment-resistance. / October 2015

Ο σκοπός αυτής της διπλωματικής εργασίας είναι η σύγκριση της αποτελεσματικότητας της ενίσχυσης, στοιχείων από φέρουσα τοιχοποιία, με μανδύες συνθέτων υλικών, οι οποίοι αποτελούνταν από στρώσεις ανθρακοϋφάσματος, με οργανική ή ανόργανη μήτρα και με τοποθέτηση ράβδων οπλισμού, από ανθρακονήματα, μέσα στους συνεχείς αρμούς της τοιχοποιίας. Αρχικά δίνονται μορφολογικά και γενικά τεχνικά χαρακτηριστικά. Γίνεται μια σύντομη ιστορική ανασκόπηση για την τοιχοποιία και ακολουθεί ο διαχωρισμός της σε βασικές κατηγορίες. Αναφέρονται οι πρώτες ύλες των τεχνητών λιθοσωμάτων και η διαδικασία παραγωγής τους και στη συνέχεια σημειώνονται τα βασικά είδη τους, με τις συνήθεις διαστάσεις και οι τεχνικές προδιαγραφές τους. Γίνεται ακόμα αναφορά στις κατηγορίες και στις ιδιότητες των κονιαμάτων και των επιχρισμάτων που χρησιμοποιούνται. Ακολουθεί μια περίληψη της μηχανικής της τοιχοποιίας. Περιγράφεται η λειτουργία της άοπλης τοιχοποιίας και ο προσδιορισμός της αντοχής της, υπό θλιπτικά, καμπτικά και διατμητικά φορτία, κατά τον Ευρωκώδικα 6 (EC6) και Τάσιο. Περιγράφονται επίσης τα ελαστικά χαρακτηριστικά της τοιχοποιίας και ο τρόπος, με τον οποίο αυτή συμπεριφέρεται υπό οριζόντια πλευρική φόρτιση, ενώ φέρει θλιπτικά φορτία. Στη συνέχεια γίνεται περιγραφή των ενισχύσεων κατασκευών με σύνθετα υλικά. Κατηγοριοποιούνται τα σύνθετα υλικά και δίνονται οι ιδιότητες των συνθέτων ινο-πλισμένων υλικών. Αναφέρονται εν συντομία οι ιδιότητες των υλικών, ινών και ρητινών, που χρησιμοποιούνται συνήθως για την κατασκευή ινοπλισμένων πολυμερών. Ακόμα αναφέρονται τα βασικά συστήματα ενίσχυσης και οι ιδιότητες των συνθέτων υλικών. Ακολουθεί η μικρομηχανική των υλικών αυτών και οι επιπτώσεις, των περιβαλλοντικών συνθηκών, στην ανθεκτικότητά τους. Επίσης, γίνεται μια περιληπτική αναφορά στις τεχνικές ενισχύσεων δομικών στοιχείων με σύνθετα υλικά. Έπεται μια σύντομη αναφορά στις βάσεις σχεδιασμού ενισχύσεων με σύνθετα υλικά. Δίνονται οι καταστατικοί νόμοι των υλικών για οριακή κατάσταση αντοχής, τόσο για πλήρη συνεργασία όσο και για αποκόλληση του συνθέτου υλικού από την κατασκευή, και για οριακή κατάσταση λειτουργικότητας. Επίσης σχολιάζεται και το θέμα της συνάφειας των συνθέτων υλικών με το υπόστρωμα (τοιχοποιία). Ακολούθως περιγράφονται τα υλικά κατασκευής και ενίσχυσης, τα πειραματικά δοκίμια και δίνονται οι μηχανικές τους ιδιότητες. Ακόμα γίνεται περιγραφή των ειδών των δοκιμίων, που δημιουργήθηκαν, της διαδικασίας ενισχύσεώς τους, σύμφωνα με τους τρόπους που είχαν αποφασιστεί, δηλαδή με κατασκευή μανδυών και με τοποθέτηση ράβδων οπλισμού από σύνθετα υλικά. Επίσης περιγράφονται εν συντομία ο μηχανικός εργαστηριακός εξοπλισμός, που χρησιμοποιήθηκε για την εκτέλεση των πειραματικών διαδικασιών. Στην συνέχεια γίνεται αναλυτική προσομοίωση για κάθε είδος δοκιμίου και ενίσχυσης, από όπου εξάγεται και η θεωρητική τιμή της αντοχής τους, και περιγραφή της πειραματική διαδικασίας, που ακολούθησε για τον έλεγχό τους. Ακολούθως, γίνεται σύγκριση μεταξύ των τρόπων ενίσχυσης και αναφορά των σχετικών πλεονεκτημάτων και τα μειονεκτημάτων τους, ανά κατηγορία δοκιμίων. Τέλος, δίνονται τα συμπεράσματα της εργασίας, που συνοπτικά είναι ότι η χρήση α-νόργανης μήτρας για την κατασκευή μανδυών προσφέρει, με σχετική μείωση της αντοχής, μεγαλύτερη παραμορφωσιμότητα και ικανότητα απορρόφησης ενέργειας και ότι η ενίσχυση, με τοποθέτηση ράβδων ανθρακονήματος, μέσα στους συνεχείς αρμούς της τοιχοποιίας, είναι επισφαλής, λόγω της μη ικανοποιητικής συνάφειάς τους με το συνδετικό κονίαμα, αποτελέσματα, τα οποία μπορούν να χρησιμοποιηθούν για την καλύτερη διαστασιολόγηση των ενισχύσεων με σύνθετα υλικά. Επίσης αναφέρονται κάποια θέματα που χρήζουν περαιτέρω μελέτης, όπως η τοποθέτηση των ράβδων ανθρακονημάτων σε άλλες θέσεις και διευθύνσεις, το απαιτούμενο ποσοστό ινών και η πιθανή τροποποίηση των πειραματικών διατάξεων, ώστε να πραγματοποιηθεί ακριβέστερη προσομοίωση των πραγματικών στοιχείων και φορτίσεων, μιας κατασκευής. / The purpose of this study is the comparison between the use of fibre-reinforced polymers (FRP) as strengthening materials for masonry walls with jackets of polymeric matrix (organic and inorganic) using carbon fabrics and strips (into the constant joints of masonry). First of all, is discribed the history of masorny and its categories. Then, are mentioned the first materials for bricks, the procedure for their produce and their sizes. Also, are mentioned the categories of mortar and plaster. Moreover, is discribed the mechanics of masonry according the Eurocode 6(EC6) and the professor Tasios. Furthermore, are reported the categories of composite materials and their qualities. Also, is annotated the connection between the composite materials and the masonry (substratum). Apart from this, are described the materials that were used to form and reinforce elements of masonry wall. Also, are described the types of elements of masonry wall, that were built, the procedure for their reinforcement and the mechanical equipment of the laboratory, where expirements took place. Moreover, are annotated the analytical model for every type of masonry element, from where theoritical values were taken and the experimental procedure. Furthermore, is presenced the comparison between every type of reinforcment and their advantages or disadvantages. Finally, are decribed subjects for future usage and results of this study.

Η εκπόνηση της Διατριβής Διπλώματος Ειδίκευσης με τίτλο «Η Μονή Στροφάδων : Αποτύπωση – Παθολογία – Προδιαγραφές Αποκατάστασης» είχε ως στόχο τη συνοπτική προσέγγιση και παρουσίαση του προβλήματος του μοναστηριακού συγκροτήματος Στροφάδων. Η εργασία αυτή δεν αποσκοπεί στο να δώσει πρακτική λύση στο πρόβλημα αποκατάστασης του μοναστηριού καθώς κάτι τέτοιο δε θα ήταν εύκολο να πραγματοποιηθεί στο πλαίσια μιας μεταπτυχιακής εργασίας. Στο πρώτο κεφάλαιο της εργασίας γίνεται μια συνοπτική αναδρομή της ιστορίας της μονής με αναφορά στα σημαντικότερα γεγονότα από την ίδρυσή της έως σήμερα. Επίσης, γίνεται αναφορά στην πνευματική, πολιτισμική και αμυντική αξία της μονής. Το δεύτερο κεφάλαιο της εργασίας αποτελεί την αρχιτεκτονική τεκμηρίωση. Καταρχήν αναφέρεται σε συντομία η υστεροβυζαντινή αρχιτεκτονική των μοναστηριών, οι τύποι ναών και τα υλικά δόμησης. Στη συνέχεια γίνεται η περιγραφή του μοναστηριακού συγκροτήματος, του πύργου και των κτισμάτων όλων των πτερύγων. Η περιγραφή αυτή γίνεται καλύτερα κατανοητή μέσα από τα σχέδια κατόψεων και τομών που παρουσιάζονται στο τέλος του κεφαλαίου. Στο τρίτο κεφάλαιο περιγράφονται οι φάσεις κατασκευής του μνημείου : υστεροβυζαντινή, η φάση Ενετοκρατίας και η νεότερη, με τα κτίσματα που περιλαμβάνει η καθεμιά, καθώς και τα χρησιμοποιούμενα υλικά και τρόποι δόμησης. Στο τέταρτο κεφάλαιο δίνεται μια εικόνα της παθολογίας του μοναστηριακού συγκροτήματος με αναφορά στις φθορές εξωτερικών τοίχων και εσωτερικού. Ακόμα, καταγράφεται η παθολογία των υλικών κατασκευής λίθων, πλίνθων, κονιαμάτων, καθώς και τα αίτια φθοράς των κτισμάτων της μονής. Στο πέμπτο κεφάλαιο της εργασίας παρουσιάζονται οι βασικές προδιαγραφές για την αποκατάσταση της μονής : Προδιαγραφές αρχιτεκτονικής και δομοστατικής μελέτης, προδιαγραφές μελέτης παθολογίας υλικών, αξιολόγηση της υφιστάμενης κατάστασης, προτάσεις συντήρησης, προσδιορισμός χρήσεων για το μνημείο και προτάσεις προσαρμογής των χρήσεων στο μνημείο. Τέλος αναφέρονται τα συμπεράσματα που προέκυψαν κατά την εκπόνηση της Διατριβής Διπλώματος Ειδίκευσης. Το κύριο συμπέρασμα η είναι η άμεση αποκατάσταση των κτισμάτων της μονής Στροφάδων. Η αποκατάσταση αυτή θα πρέπει να αποτελεί έργο υπεύθυνης και συντονισμένης προσπάθειας μιας ομάδας αναστηλωτών που θα σέβονται την ιστορική και αρχιτεκτονική αξία του μνημείου. Επίσης, οι επεμβάσεις θα πρέπει να σχεδιαστούν έτσι, ώστε να διατηρείται η αρχιτεκτονική και κατασκευαστική ταυτότητα του μνημείου. / The elaboration of the thesis entitled “ Monastery of Strofades : Survey – Pathology – Outline of Restoration “ aims at the brief approach and presentation of the problem of the monastery of Strofades. This thesis does not aim at giving a practical solution to the problem of restoration of the monastery since the latter is difficult to be achieved in terms of postgraduate studies. In the first chapter, a brief retrospection of the history of the monastery takes place with reference to the most significant events from its establishment till today. Moreover, this thesis refers to cultural and defensive value of the monastery. The second chapter constitutes the architectural presumption. Firstly, it is made a brief reference to the metabyzantine architecture of monasteries, the types of temples and the constructing materials. Then, a description of the monastery, the tower and the other parts of the construction takes place. This description can be better understood through the designs of the ground plans presented at the end of the chapter. In the third chapter, are different phases of the construction of the monument, the metabyzantine phase, the Venetian phase and the modern one together with the constructions placed at each phase as well as the materials used and the ways of construction. In the fourth chapter of this thesis, it is given a picture of the pathology of the monastery with reference to the damages of both the exterior walls and the interior. Moreover, the pathology of the constructing materials, stones, bricks and mortars, and the causes of damages of the construction of the monastery as well as listed. In the fifth chapter, are presented the basic prescriptions for the restoration of the monastery. Prescriptions of the architectural study, of the pathology of the materials, evaluation of the existing situation, proposals of maintenance, determination of usages for the monument as well as proposals of adaptation of those usages to the latter. To sum up, the conclusions drawn from this thesis are mentioned in the end. The main conclusion is that it is needed the immediate restoration of the construction of the monastery of Strofades. This restoration should constitute a work of responsible and coordinated effort of a group of restorers who will respect the historical and architectural value of the monument. Last but not least, the interventions must be designed in such way so as to preserve the architectural and structural identity of the monument.

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This thesis focuses on the seismic behaviour of reinforced concrete structures with masonry infills, with particular interest in the development of rational procedures for the design and analysis of this type of structure. The properties of masonry and its constitutive materials were reviewed, giving special emphasis to those aspects which contribute to a better understanding of the strength mechanism. Theoretical procedures were developed for the rational evaluation of the strength of masonry subjected to compressive and shear stresses. A large amount of experimental work related to the behaviour of infilled frames was also reviewed. The main characteristics of the response under lateral loading were discussed for different types of infilled frames and a comprehensive classification of the modes of failure, for both the masonry panel and the surrounding frame, was conducted. In addition, the influence of several parameters which can affect the structural response was evaluated. Two theoretical procedures, with different degree of refinement, are proposed in this study for the analysis of infilled frames. The first procedure is a simple approach, based on the equivalent truss mechanism, which allows the evaluation of the lateral resistance of the infilled frames, considering two different types of failure in the masonry panel, namely, shear-friction and diagonal tension failure. The compressive strength of the diagonal strut is assessed by transforming the shear failure envelope obtained from the modification of the Mann and Muller's theory. This transformation takes into account the inclination of the diagonal strut and neglects the effect of the tensile principal stresses acting on the masonry panel. The second procedure is a refined macroscopic model based on a multi-strut formulation, which is intended to represent more accurately the effect of the masonry panel on the surrounding frame. Since debonding of the mortar joints is the most common type of failure observed in the masonry panel, the formulation of the procedure is specifically developed to represent this situation. The model accounts separately for the compressive and shear behaviour of masonry using a double truss mechanism and a shear spring in each direction. Recommendations are also given for the analysis of infilled frames when a failure due to diagonal tension or crushing of the corners is expected in the panel. A test programme was implemented to investigate the seismic response of infilled frames. The main criterion followed for the design was that the reinforced concrete columns should yield in tension in order to obtain a reasonable ductile response under lateral loading. New reinforcing details were provided in one unit, aimed at enhancing the structural response. These details consisted in tapered beam-column joints with diagonal reinforcement, and additional longitudinal reinforcement in the frame members. The additional bars placed in the columns were not anchored to the foundation in order to produce a weak region at the base of the columns, where most of the plastic deformations were expected to occur. The most important conclusion of the experimental programme is that the response of reinforced concrete frames with masonry infills can be significantly improved by a rational design aimed at reducing the distortion of the masonry panels while plastic deformations arc concentrated in selected regions of the structure. A new design approach is proposed for infillcd frames, in which two cases are considered: cantilever and squat infillcd frames. In the first case, the ductile behaviour is achieved by yielding of the longitudinal reinforcement, which is limited to occur only at the base ofthe columns, and by avoiding large elongations of the remaining parts of the surrounding frame. A pre-cracked connection is induced between the infilled frame and the foundation, where plain round dowels can be placed to control shear sliding. In the second case, ductility is conferred to the structure by allowing controlled sliding of the infillcd frame over the foundation. The applicability of this approach is limited to those cases where the total shear force exceeds the frictional strength of the pre-cracked connection. The effectof pinching of the hysteresis loops in the response of infilled frames subjected to earthquakes was investigated. A parametrie study was conducted using a one-degree-of-freedom oscillator subjected to ground accelerations recorded in five different earthquakes. Results obtained from the dynamic nonlinear analyses indicated that the effect of pinching and the damping model used can significantly influence the response of infilled frames, which normally exhibit a short to medium initial period of free vibration. Therefore, the displacement demand imposed by the earthquake can be larger than that assumed by the seismic codes if they are based on the concept of equal displacement.

This thesis focuses on the seismic performance of unreinforced masonry wall perforated with a door opening representing typical URM walls of many aged masonry buildings in Indonesia. To obtain a test result that will be able to represent the local conditions, the experiments have been conducted in the Research Institute for Human Settlements (RIHS) laboratory in Bandung-Indonesia. Two 75 % unreinforced masonry (URM) walls with a 1½-wythe of solid clay-brick were constructed in Dutch bond configuration and tested until failure under quasi-static-reversed cyclic loading. Both units were loaded vertically by constant loads representing gravity loads on the URM wall’s tributary area. Both models were constructed using local materials and local labours. Two features were taken into account. First, it accommodated the influence of flanged wall and second, the URM wall was built on the stone foundation. The first URM wall represent the plain existing URM building in Indonesia and second strengthened by Kevlar fibre. It was observed from the test results that the URM wall Unit-1 did not behave as a brittle structure. It could dissipate energy without loss of strength and had a post-elastic behaviour in terms of “overall displacement ductility” value of around 8 to 10. As predicted, the masonry material was variable and non homogeneous which caused the hysteresis loop to be non symmetrical between push and pull lateral load directions. It can be summarized that Kevlar fibre strengthening technique is promising and with great ease of installation. Although Kevlar material is more expensive when compared to other fabrics as long as it was applied at the essential locations and in limited volumes, it can significantly increase the in-plane URM wall capacity. With appropriate arrangements of Kevlar fibre, a practicing engineer will be able to obtain a desired rocking mechanism in the masonry structure. Another advantage for the architectural point of view, very thin Kevlar fibres do not reduce the architectural space. Studies have also been undertaken to analyze the in-plane response of plain URM wall before and after retrofiting using the current seismic standard and the Finite Element Method (FEM).

Masonry arch bridges have played a significant role in the road and rail transportation network in the world for centuries. They are exposed to damage due to overloading and deterioration caused by environmental actions. In order to reestablish their performance and to prevent their collapse in various hazardous conditions, many of them require strengthening. Fibre reinforced polymer (FRP) systems are increasingly used for repair and strengthening of structures, with particularly widespread application to concrete structures. However, the application of FRP composites to masonry structures is less well established due to the complexity of masonry caused by the material discontinuity. FRP strengthening masonry arch bridges has been even less studied due to the additional complexity arising from the co-existence of the normal interfacial stress and the shear interfacial stress at the curved FRP-to-masonry bondline. This thesis presents an extensive study investigating the behaviour of FRP strengthened masonry bridges. The study started with a laboratory test of a two span masonry arch bridge with sand backfill. A single ring arch bridge was first tested to near failure, and then repaired by bonding FRP into their intrados and tested to failure. It was found that the FRP strengthening not only improved the loading capacity and stiffness of bridge, but also significantly restrained the opening of cracks in the masonry. Shear and peeling debonding of FRP was observed. There have been two common strategies in finite element (FE) modelling of FRP strengthened structures in meso-scale: direct model and interface model. The former is necessary when investigating the detailed bond behaviour but challenges remain due to the difficulties in concrete modelling. A new concrete damage model based on the plastic degradation theory has been developed in this study to study the bond behaviour of FRP strengthened concrete structure. This robust model can successfully capture this bond behaviour and simulate the entire debonding process. A numerical study of masonry arch bridges including the backfill was conducted to study the behaviour of masonry arch bridge. A total of four modelling strategies were examined and compared. Although they all can successfully predict the behaviour of arch, a detailed solid model newly developed in this study is more suitable for modelling both plain masonry and FRP strengthened structures. Finally, a numerical study of bond behaviour and structural response of FRP strengthened masonry arch structures with sand backfill was conducted. In addition to the masonry and backfill, the mixed mode interfacial behaviour was modelled by the aforementioned interface model strategy and investigated in detail to achieve a deeper understanding of the behaviour of FRP strengthened masonry arch structures. The results are in close agreement with test results, and highlight the influence of the key parameters in the structural response to failure and revealed the mechanisms on how the load is transmitted through this complex multi-component structural system.

Craftsmen of past generations built to last, and the brick buildings they constructed can last for centuries if they are not mistreated. Although brick masonry is one of the most durable building materials, its durability can be threatened by improper cleaning and repointing techniques and materials. Many brick surfaces have been--and currently are being--disfigured, and the rate of deterioration often accelerated, because of the lack of knowledge of proper preservation techniques for historic bricks and mortar.This field guide provides a single source of information regarding inspection of historic brick buildings; the causes of deterioration, diagnoses and treatments; appropriate materials and methods for repointing; various cleaning methods; and surface coatings (including waterproof and water-repellent coatings, paint and stucco). This manual can be used to assist persons responsible for the care of old and historic brick buildings: owners of houses or commercial buildings, administrators, architects, contractors, and anyone else who wants to maintain or sympathetically restore or rehabilitate brick buildings.While masonry work generally should only be done by professionals, this field guide will enable a building owner or administrator to understand proper preservation techniques and oversee the project to ensure that the architect or contractor is following the recommended preservation procedures. The Mississippi Department of Archives and History will use this creative project as a reference manual and as a handout to persons undertaking restoration of historic brick buildings.Historic architecture is a viable link between generations of the past and those of the present and future. Proper maintenance and restoration techniques can ensure that a historic brick building will endure for generations to come. / Department of Architecture