Influence of masonry steel reinforcement on the in-plane behavior of infilled rc frames

Numerous typologies for the layout of steel bars in reinforced masonry members have been proposed in the literature and in relevant design codes. Given that such reinforcement can increase the load-bearing capacity and ductility while also reducing the susceptibility to damage of clay block masonry members, it follows that it can also enhance the behavior of such members in their role as infill in reinforced concrete frames. This contribution may be crucial in the structural safety of new and existing reinforced concrete structures in seismic prone areaPostprint (published version

Numerical Analysis of a Masonry Infill (Divided Into Smaller Wallettes) Under in-Plane Cyclic Tests

asonry infill in reinforced concrete frames has been recognised as being a strong factor influ- encing the seismic behaviour of buildings. Therefore, the development of innovative infill systems, coupled with the rigorous study of their behaviour, is of significant importance. Within the framework of the IN- SYSME project (http://www.insysme.eu/), a new infill system was designed and tested. The defining feature of the system, composed of clay units, is the division of the masonry wall into smaller, and thus more flexible, wallettes separated by vertical joints. The frames are subjected to in-plane cyclic shear loading to the point of irreversible damage of the masonry. Subsequently, the experiments are simulated using nonlinear finite ele- ment analysis in an effort to highlight the features of the response of the actual structure, to predict the maxi- mum force and to reproduce the failure modPostprint (published version

Assessment of innovative solutions for non-load bearing masonry enclosures

This paper presents some of the results of the research project “Masonry Enclosures” developed in the framework of the transnational access (TA) to LNEC’s triaxial shake table within the FP7 project SERIES.In order to ensure that in-plane and out-of-plane damage of masonry infill walls due to seismic actions complies with the performance levels’ requirements, Eurocode 8 imposes the use of reinforced solutions. Nevertheless, it does not provide any design rules or methodologies for such reinforced masonry enclosures. An experimental programme was thus defined for assessing the response of innovative solutions for non-load bearing masonry enclosures using LNEC’s triaxial shake table. Two reinforcement solutions were tested on single leaf clay brick infill walls: (i) horizontal reinforcement in the bedding planes of the masonry units and (ii) reinforced mortar coating. Furthermore, a testing device for masonry infill panels was specifically conceived for this project. A detailed description of the methods used is given and the experimental results are partially presented and interpreted on the basis of the structural response and its evolution with damage.(undefined

Seismic behaviour of reinforced interfaces in repaired/ strengthened reinforced concrete elements

The aim of the Doctoral Dissertation is the study of the mechanisms (concrete-to-concrete friction and dowel action of the reinforcing bars crossing the interface), acting along the interface between the old and the new concrete, subjected to cyclic actions. The interfaces under investigation are met in repaired/ strengthened RC elements, in case a new concrete layer or new RC elements are added to the existing members of the structure. In the international literature, data regarding the behaviour of reinforced interfaces in repaired/strengthened elements, subjected to cyclic shear slip are rather scarce. In order to cover this lack of knowledge, the present Dissertation focuses in a systematic (in depth and extent) experimental research of the interaction of the mechanisms for the shear transfer along RC interfaces, for cyclic actions. Based on the results of the abovementioned experimental research, important conclusions can be drawn as well as the fundamentals for a design method for strengthened RC elements (mainly under cyclic actions). A constitutive law has been proposed, for the accurate prevision of the maximum interface resistance, the force-response degradation and the full shear load-slip diagram. The proposed law is simple enough and physically sound in order to be easily used in analytical models for the design of interfaces in repaired or strengthened RC elements subjected to cyclic actions. Through the analytical models it will be possible to evaluate the contribution of the selected strengthening technique, as well as of the characteristics of the interface, in the overall behaviour of the repaired/ strengthened RC elementsΤο αντικείμενο αυτής της Διατριβής είναι η μελέτη των μηχανισμών (τριβή και δράση βλήτρου του οπλισμού που τέμνει την διεπιφάνεια), οι οποίοι επιστρατεύονται στην διεπιφάνεια μεταξύ παλαιού και νέου σκυροδέματος, υπό σεισμικές δράσεις. Πρόκειται για διεπιφάνειες σε στοιχεία υφιστάμενων κατασκευών Ω.Σ. μετά από την επισκευή ή την ενίσχυσή τους.Στην διεθνή Βιβλιογραφία δεν διατίθενται στοιχεία για την συμπεριφορά σε ανακύκλιση των ωπλισμένων διεπιφανειών σε επισκευασμένα/ ενισχυμένα στοιχεία. Για την κάλυψη του διαπιστούμενου κενού, η παρούσα εργασία επικεντρώθηκε σε μια συστηματική (σε βάθος και έκταση) πειραματική μελέτη της ταυτόχρονης δράσης των μηχανισμών για την μεταφορά τέμνουσας κατά μήκος διεπιφανειών Ω.Σ., για ανακυκλιζόμενες δράσεις. Προσφέρονται οι βάσεις για μια μέθοδο σχεδιασμού ενισχυμένων στοιχείων από Ω.Σ. (ιδίως υπό ανακυκλιζόμενη τέμνουσα) με βάση τα αποτελέσματα της ως άνω πειραματικής διερεύνησης. Διατυπώθηκε καταστατικός νόμος, μέσω του οποίου είναι δυνατόν να προβλεφθεί η μέγιστη απόκριση της διεπιφάνειας, η μείωση της απόκρισης με την ανακύκλιση της ολίσθησης και το πλήρες διάγραμμα φορτίου-ολίσθησης. Ο νόμος αυτός είναι αρκετά απλός, ώστε να είναι δυνατόν να τροφοδοτήσει αναλυτικά προσομοιώματα επισκευασμένων/ενισχυμένων στοιχείων ωπλισμένου σκυροδέματος, μέσω των οποίων θα καταστεί δυνατή η εκτίμηση της συνεισφοράς της επέμβασης που επελέγη, καθώς και των χαρακτηριστικών της διεπιφάνειας στην συνολική συμπεριφορά των στοιχείων

Numerical analysis of the out-of-plane response of two new systems for masonry infills

he out-of-plane behaviour of two new systems for infill walls, made of clay masonry units, is numerically investigated. The two systems were developed within the INSYSME project. In the first system the enclosure wall is divided into smaller wallettes by means of soft vertical joints, whereas in the second sys- tem horizontal and vertical reinforcement is provided. In the latter system, a special brick unit, capable of ac- commodating steel reinforcement and electrical and plumbing installations, was designed. In both systems, simple sliding connectors are arranged to prevent the out-of-plane collapse of the infills. An experimental campaign was carried out, involving repeated out-of-plane tests on infilled frames. The walls were subjected to distributed loads, applied through the use of a specially designed steel frame. Both systems exhibited significant capacity for load bearing and deformation.Postprint (published version