Twenty full-scale unreinforced masonry walls were constructed and tested to failure in the Structures Laboratory at the University of Saskatchewan. The focus of the testing related to two primary objectives. The first objective was to study the effects that the support conditions of the walls had on their behaviour. The masonry wall specimens tested spanned vertically under the application of out-of-plane loads. Ten of the full scale walls were tested with support conditions that modeled ideal pinned connections at the top and bottom of the wall, while the remaining half of the walls were tested with nominally “pinned” supports that were similar to the supports typically encountered in practice. The second objective was to determine the effects that dynamic loads had on the behaviour of the walls. Half of the masonry specimens for each group of support conditions were loaded laterally with monotonically increasing quasi-static loads representative of the effects of uniform wind pressure, while the remaining specimens were loaded laterally with dynamic time histories that varied randomly in a manner that was representative of real “gusty” winds. The research was therefore done to determine the influence of load and connection type on the behavior of the masonry walls. When comparing the effects of the support conditions, it was found that the walls constructed with realistic support conditions were able to resist larger out-of-plane loads, with greater ductility than the walls that had ideally-pinned supports. Specifically, the realistically-pinned walls required an average moment (of both the statically and dynamically loaded walls) that was 63% larger to cause mid-height cracking than the average mid-height moment required to cause mid-height cracking in the ideally-pinned walls. After mid-height cracking occurred, the realistically-pinned walls exhibited reserve capacity, resulting in additional strength, such that the ultimate moment capacity of the realistically-pinned walls was 140% greater than the ultimate strength of the ideally-pinned walls, where the ultimate strength was the capacity of the wall at mid-height cracking. As a result, the ductility of the realistically-pinned walls was also significantly larger than that of the ideally-pinned walls. Specifically, the ductility ratio of the realistically-pinned walls was 70 (where the ductility ratio is defined as the displacement at the ultimate load divided by the displacement at mid-height cracking), while the ductility ratio of the ideally-pinned walls was unity (the ultimate load coincided with formation of the mid-height crack). The results of the dynamically and quasi-statically loaded walls were harder to evaluate. In comparing the ideally-pinned walls it was found that the specimens that were loaded dynamically had an average moment capacity that was approximately 10% larger than the walls that were loaded quasi-statically, which was found to be statistically significant at the 90% level. However, the results from the realistically-pinned walls were not as conclusive. At mid-height cracking the dynamically loaded walls had an average moment capacity that was 24% lower than the quasi-statically loaded walls, which seems to contradict with the data from the ideally-pinned walls and from the literature suggesting that dynamic strengths should be higher. At the ultimate condition, the dynamically loaded walls had an average strength that was 12% larger than the quasi-statically loaded walls; however, these comparative results were not statistically significant at the 90% confidence level. It was also found that the dynamic loading failed the wall specimens as a result of sustained, large amplitude “gusts” rather than at the largest instantaneous peak load. The displacement behaviour of the walls was generally independent of the method of loading, but, rather, largely dependent on the support conditions. The collapse of the wall specimens were all initiated when they reached a geometrically unstable displaced shape that was fairly consistent for a given support configuration, regardless of the type of load that was applied. Lastly, results from a numerical model suggested that the dynamically loaded walls exhibited higher apparent stiffness properties as compared to the quasi-statically loaded walls. The difference in the apparent stiffness between the dynamic and quasi-static specimens decreased with increasing damage levels until the dynamic stiffness converged to the static stiffness near the collapse of the walls.

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).

Unreinforced masonry construction is considered to be the most vulnerable forms of construction as demonstrated through recent earthquakes. In Canada, many densely populated cities such as (Vancouver, Montreal and Ottawa) have large inventories of seismically vulnerable masonry structures. Although measures have been taken to rehabilitate and increase the seismic resistance of important and historic structures, many existing unreinforced masonry structures have not been retrofitted and remain at risk in the event of a large magnitude earthquake. There is therefore a need to identify buildings at risk and develop tools for assessing the seismic vulnerability of existing unreinforced masonry structures in Canada. This thesis presents results from an ongoing research program which forms part of a multi-disciplinary effort between the University of Ottawa’s Hazard Mitigation and Disaster Management Research Centre and the Geological Survey of Canada (NRCAN) to assess the seismic vulnerability of buildings in dense urban areas such as Ottawa, Ontario. A risk-based seismic assessment tool (CanRisk) has been developed to assess the seismic vulnerability of existing unreinforced masonry and reinforced concrete structures. The seismic risk assessment tool exploits the use of fuzzy logic, a soft computing technique, to capture the vagueness and uncertainty within the evaluation of the performance of a given building. In order to conduct seismic risk assessments, a general building inventory and its spatial distribution and variability is required for earthquake loss estimations. The Urban Rapid Assessment Tool (Urban RAT) is designed for the rapid collection of building data in urban centres. This Geographic Information System (GIS) based assessment tool allows for intense data collection and revolutionizes the traditional sidewalk survey approach for collecting building data. The application of CanRisk and the Urban RAT tool to the City of Ottawa is discussed in the following thesis. Data collection of over 13,000 buildings has been obtained including the seismic risk assessment of 1,465 unreinforced masonry buildings. A case study of selected URM buildings located in the City of Ottawa was conducted using CanRisk. Data obtained from the 2011 Christchurch Earthquake in New Zealand was utilized for verification of the tool.

Unreinforced masonry construction is considered to be the most vulnerable forms of construction as demonstrated through recent earthquakes. In Canada, many densely populated cities such as (Vancouver, Montreal and Ottawa) have large inventories of seismically vulnerable masonry structures. Although measures have been taken to rehabilitate and increase the seismic resistance of important and historic structures, many existing unreinforced masonry structures have not been retrofitted and remain at risk in the event of a large magnitude earthquake. There is therefore a need to identify buildings at risk and develop tools for assessing the seismic vulnerability of existing unreinforced masonry structures in Canada. This thesis presents results from an ongoing research program which forms part of a multi-disciplinary effort between the University of Ottawa’s Hazard Mitigation and Disaster Management Research Centre and the Geological Survey of Canada (NRCAN) to assess the seismic vulnerability of buildings in dense urban areas such as Ottawa, Ontario. A risk-based seismic assessment tool (CanRisk) has been developed to assess the seismic vulnerability of existing unreinforced masonry and reinforced concrete structures. The seismic risk assessment tool exploits the use of fuzzy logic, a soft computing technique, to capture the vagueness and uncertainty within the evaluation of the performance of a given building. In order to conduct seismic risk assessments, a general building inventory and its spatial distribution and variability is required for earthquake loss estimations. The Urban Rapid Assessment Tool (Urban RAT) is designed for the rapid collection of building data in urban centres. This Geographic Information System (GIS) based assessment tool allows for intense data collection and revolutionizes the traditional sidewalk survey approach for collecting building data. The application of CanRisk and the Urban RAT tool to the City of Ottawa is discussed in the following thesis. Data collection of over 13,000 buildings has been obtained including the seismic risk assessment of 1,465 unreinforced masonry buildings. A case study of selected URM buildings located in the City of Ottawa was conducted using CanRisk. Data obtained from the 2011 Christchurch Earthquake in New Zealand was utilized for verification of the tool.

This study focuses on the evaluation of seismic safety of masonry buildings in Turkey by using fragility curves. Fragility curves for masonry buildings are generated by two behavior modes for load bearing walls: in-plane and out-of-plane. By considering the previous research and site investigations, four major parameters have been used in order to classify masonry buildings with in-plane behavior mode. These are number of stories, strength of load-bearing wall material, regularity in plan and the arrangement of walls (required length, openings in walls, etc.). In addition to these four parameters, floor type is also taken into account for the generation of fragility curves by considering out-of-plane behavior mode. During generation of fragility curves, a force-based approach has been used. In this study there exist two limit states, or in other words three damage states, in terms of base shear strength for in-plane behavior mode and flexural strength for out-of-plane behavior mode. To assess the seismic vulnerability of unreinforced masonry buildings in Turkey, generated fragility curves in terms of in-plane behavior, which is verified by damage statistics obtained during the 1995 Dinar earthquake, and out-of-plane behavior, which is verified by damage statistics obtained during the 2010 Elazig earthquake, is combined. Throughout the analysis, ground motion uncertainty, material variability and modeling uncertainty have also been considered. In the final part of the study, a single-valued parameter, called as &lsquo / vulnerability score&rdquo / , has been proposed in order to compare the seismic safety of unreinforced masonry buildings in Fatih sub province of Istanbul and to assess the influence of out-of-plane behavior together with the in-plane behavior of these existing masonry buildings.

Μια από τις πολλές δομικές εφαρμογές των συνθέτων υλικών, είτε αυτά έχουν την μορφή ινοπλισμένων πολυμερών είτε την μορφή ινοπλισμένων κονιαμάτων, είναι και η ενίσχυση τοιχοποιίας, φέρουσας ή μη. Τα σύνθετα υλικά είναι δυνατό να δώσουν λύση σε προβλήματα στατικής επάρκειας και αναβάθμιση στάθμης επιτελεστικότητας κτηρίων σύμφωνα με τους Ευρωκώδικες. Ο στόχος της συγκεκριμένης μεταπτυχιακής διατριβής είναι: i. Να μελετηθούν οι τρόποι με τους οποίους είναι δυνατόν να ενισχυθεί μια τοιχοποιία από οπτοπλινθοδομή και να πραγματοποιηθούν πειραματικές δοκιμές, (για να καταστεί με αυτό τον τρόπο δυνατή η σύγκριση των θεωρητικών με τα πειραματικά δεδομένα). ii. Η κατασκευή αντιπροσωπευτικών δοκιμίων που να εξετάζουν και να απεικονίζουν την πλειονότητα των δομημάτων και τελικά η πειραματική επεξεργασία τους. iii. Η επιλογή των κατάλληλων υλικών με τα οποία είναι δυνατή η αποτελεσματική και πρακτική η ενίσχυση της τοιχοποιίας. iv. Η μελέτη του τρόπου με τον οποίο αλληλεμπλέκονται τα σύνθετα υλικά με την τοιχοποιία και η τελική αστοχία της τελευταίας, με στόχο την απόκτηση μεγαλύτερης αντοχής και πλαστιμότητας. v. Η σύγκριση των τρόπων ενίσχυσης με ανόργανη (τσιμεντοκονίαμα) και οργανική (εποξειδική ρητίνη) μήτρα και ανθρακονήματα. vi. Η εφαρμογή και εκτίμηση της αποτελεσματικότητας της ενίσχυσης με ράβδους ινών άνθρακα σε βαθιά αρμολογημένο τοίχο με την βοήθεια εποξειδικού τσιμεντοκονιάματος. vii. Η εκτίμηση κατά πόσο με την βοήθεια ενίσχυσης φέρουσας οπτοπλινθοδομής με σύνθετα υλικά είναι δυνατή η κάλυψη των σύγχρονων αντισεισμικών απαιτήσεων. / One of the many uses of composite materials, either in the form of fiber reinforced plastics "FRP" either in the form of fiber reinforced mortars, is the structural reinforcement of masonry. The composite materials are capable to provide a structural upgrade to a building so that it meats the contemporary eurocode demands. The goal of this master thesis is: 1. to study the possible ways of brick masonry reinforcement and perform experimental studies (so that it become possible to compare the theoretical with the experimental data) 2. the construction of representative experimental specimens that examine end picture the majority of civil masonry constructions end finally the experimental elaboration of these specimens. 3. The selection of the suitable material with witch it is possible end practical the reinforcement of the masonry. 4. The study of the ways that composite materials collaborate with the brick masonry up to the point of destruction end finding a way that the reinforced specimens would have more strength end ductility than the unreinforced ones. 5. The comparison end effectiveness of the specimens reinforced with inorganic matrix (cement mortar) versus the ones reinforced with organic matrix (epoxy resin) end carbon fibers. 6. The application end estimation of the effectiveness of carbon fiber bar reinforcement that is applied near the surface in the bed joints of the masonry specimens with the help of epoxy resin cement mortar. 7. To estimate if it is possible with the help of composite materials to reinforce masonry so that it meats contemporary antiseismic construction demands.

L’objectif principal de cette étude est de développer des outils de simulation numérique pour évaluer la vulnérabilité des constructions en maçonnerie sous chargements variés. Ainsi, le comportement de la maçonnerie non armée sous chargement monotone en macro- et micro-échelles est étudié. La simulation du comportement non linéaire du mur de maçonnerie avant et après le pic et la capture de son mécanisme de rupture sont les points centraux de ce travail. Tout d'abord, le mur de maçonnerie d’un panneau est remplacé par deux barres simples utilisant la stratégie des macros-éléments et un comportement tri-linéaire est proposé pour évaluer la résistance à la rupture de la paroi ainsi que son comportement avant et après le pic. L'absence de l'information sur le mécanisme de rupture du mur de maçonnerie et la relation entre le mécanisme de rupture et les propriétés mécaniques des éléments barres dans ce type de modélisation conduisent à opter pour une autre description de ces structures à savoir la stratégie de micro-modélisation. Dans cette stratégie, les unités et les mortiers sont modélisés séparément et l’ensemble du comportement inélastique du mur de maçonnerie est supposé se produire dans les mortiers. Par conséquent, une attention particulière sera accordée au développement d'une description fiable des propriétés matérielles de ces éléments à l'aide d'une loi constitutive précise. La représentation tridimensionnelle d'un mur de maçonnerie faite dans ce travail, améliore la capacité des méthodes actuelles pour prédire le comportement de la maçonnerie sous les deux chargements en plan et hors du plan. D’abord, des enveloppes de rupture comprenant la tension limite et la surface de charge de Mohr-Coulomb sont assignées à l'élément d'interface du code éléments finis GEFDyn. Ensuite, la loi de comportement est améliorée en ajoutant un seuil de compression aux surfaces de charge pour inclure l’endommagement en compression de la maçonnerie à travers l'élément d'interface. Dans le nouveau modèle élastoplastique, les écrouissages négatifs des seuils de traction et de compression ainsi que la cohésion du mortier sont pris en considération. La capacité des deux modèles pour reproduire le comportement avant et après le pic de la résistance au cisaillement du mur de maçonnerie est vérifiée en comparant les résultats numériques avec les données expérimentales. L'importance de l’interaction entre les seuils de compression et celui du cisaillement est montrée en comparant les résultats obtenus avec ceux d'un test réel. Les résultats ont révélé que le second modèle est capable de simuler le comportement du mur de maçonnerie avec une bonne précision. Ensuite, l'effet des propriétés géométriques de la paroi telles que l’existence d’une ouverture et l'élancement, les propriétés des mortiers comme la cohésion, la résistance en traction et la résistance en compression ainsi que la contrainte verticale initiale dans le mur, sur la résistance latérale et le mécanisme de rupture des murs de maçonnerie est démontré. En outre, afin de présenter l’état d’endommagement, des indices de dommage, portant sur la longueur totale des fissures dans différentes rangées et colonnes de mortiers sont introduits et comparés pour différentes configurations. Les longueurs de glissement et d’ouverture de fissures dans les mortiers horizontale et verticale respectivement, sont les paramètres les plus importants qui contrôlent le comportement du mur. Enfin, la relation entre les profils de fissuration différents et les propriétés des matériaux y contribuant sont résumées dans un tableau. / The aim of this thesis is to develop numerical models for evaluating the vulnerability of unreinforced masonry construction under different types of loading. Therefore, the behavior of unreinforced masonry panels under monotonic loading in both macro- and micro- scales is studied. Simulating the nonlinear behavior of the masonry wall in pre and post-peak regions and capturing its failure mechanism is the main focus of this study. First, the masonry wall in the panel is substituted by two simple bars using the so-called macro-element strategy and a tri-linear behavior is proposed to assess the ultimate strength of the wall as well as its response before and after peak. The lack of information about the failure mechanism of the masonry wall and relation between the failure mechanism and mechanical properties of the bar elements in this type of modeling lead to another description of this structure namely micro-modeling strategy. In this strategy, units and mortars are modeled separately and all inelastic behavior of the masonry wall is supposed to happen in mortars. Hence, special attention is paid to development of a reliable description of material properties for these elements using an accurate constitutive law. Three dimensional representation of a masonry wall in this work enhances the capability of existing methods to predict the masonry behavior under both in-plane and out-of-plane loadings. Firstly, failure envelopes including tension cut-off and the Mohr-Coulomb yield surface are assigned to interface elements in GEFDyn finite element software. Then, the elstoplastic constitutive law is improved by adding a compression cap to the yield surfaces in order to include compressive failure of masonry in the interface element. In the new model, softening behavior for tensile and compressive strength as well as cohesion of mortar is considered. The ability of both models to reproduce the pre- and post-peak behavior of the masonry wall is verified by comparing the numerical results with experimental data. The importance of defining the compression failure of masonry by limiting the shear strength of the wall with its compressive strength is shown by comparing the obtained results with those of a real test. The results showed that the second model is capable to simulate the behavior of masonry wall with a good accuracy. Then, the effect of initial stresses and geometrical properties of the wall such as opening and aspect ratio and material properties of the mortar like its cohesion, tensile strength and compressive strength, on lateral strength and failure mechanism of the masonry walls are demonstrated. Moreover, in order to comprehend failure characteristics damage indexes based on the total length of cracks in different rows and columns of mortars are introduced and compared for different configurations. The lengths of sliding in horizontal mortars and opening in vertical ones are the most important parameters that control the behavior of the wall. Finally, the relation between different cracking profiles and contributing material properties are summarized into a table.

Unreinforced masonry (URM) structures have shown tobe susceptible to significant damage during strong earthquakes. Vulnerability assessment of URM buildings is needed so that appropriate mitigation strategies can be implemented. The existing Canadian practice consists of rapid seismic screening of buildings to assign priorities for further and more refined assessments, followed by refined analysis of individual critical buildings. The current seismic screening procedure, from 1992, is based on qualitative observations of seismic vulnerability, enabling the assignment of seismic priority indices, quantified on the basis of expert opinion and experience. More refined tools are needed for seismic vulnerability assessment of URM buildings in Canada, based on the current Canadian seismic hazard values. The objective of the research project is to fulfill these needs by developing fragility curves that provide a probabilistic assessment of different levels of building performance under different intensities ofeastern and western seismicity. Using an inventory of over 50,000 structures, a seismic assessment of typical low-rise and mid-rise URM structures located in eastern and western Canada was carried out. The required analyses were done using applied element method software which effectively modeled the in-plane and out-of-plane behaviour of masonry walls. Using incremental dynamic analysis, fragility curves were developed to reflect the capacity of URM structures with a wide variety of selected structural and ground motion parameters. The results were verified against available fragility information in the literature. They show the significance of selected parameters, while providing effective tools for seismic vulnerability assessment of URM buildings in eastern and western Canada.

The Point Sur Lighthouse is an unreinforced stone masonry building completed in 1889 on the central coast of California. The lighthouse is listed on the National Register of Historic Places and is still an active aid to navigation. The original first-order Fresnel lens was removed from the lantern room and placed in safekeeping due to its high risk of damage in the event of a strong earthquake. The lens has been approved to return to its original setting but the seismic performance of the building must first be assessed in order to ensure the safety of the lens and lighthouse, specifically the out-of-plane behavior of the unreinforced masonry walls, the implementation of possible seismic retrofit schemes, and the effects of the lens’s added weight. This research focuses on the dynamic behavior of the lighthouse in its current state and the changes in the dynamic behavior each of the proposed seismic retrofit schemes might cause. For the purposes of this research, dynamic behavior is considered as natural frequencies, mode shapes, and related structural properties. The dynamic behavior of the lighthouse was assessed using two main methods: forced vibration testing and finite element computer modeling. Forced vibration testing is a nondestructive testing method that can be used to directly characterize dynamic behavior of a structure, and finite element computer modeling is useful for the design and simulation of dynamic behavior of both new and existing structures. The combination of these two methods on the Point Sur Lighthouse will work to develop and prove state-of-the-art seismic retrofitting techniques.

No description available.