This research work proposes methods to rises the resistance and to evaluate the behavior of confined masonry walls built from clay solid bricks. These elements are widely used in Guerrero State (México) to build masonry structures, which should resist high lateral loads because of the serious seismic hazard. Therefore, a large experimental program to evaluate the mechanical properties of bricks and masonry currently required in the design process and masonry analysis was developed. To rises the masonry resistance and to counteract the influence of the compressive strength of the pieces on the masonry behavior, a high compressive strength mortar and a metallic reinforcement inside the joints were used. With respect to referenced values of the mechanical properties, some were similar and others were twice bigger. In this country zone, the first three tests under lateral load on full-scale confined masonry walls built from clay solid bricks were carried out in order to evaluate its behavior. A reinforcement composed by metallic hexagonal mesh-mortar coat was placed on the faces of two walls to rise or to restore the resistance. The walls showed good behavior and the reinforcement had adequate structural efficiency. Numerical models of panels and walls built by using the experimental data evaluated the envelope resistance, the failure mode and showed the influence of the mechanical properties of the pieces and joints on the global behavior. Two models had metallic reinforcement inside the joints. In addition, a constitutive law of the masonry defined from experimental results allowed to elaborate a simple model, which results were concordant with respect to the experimental results and similar to those calculated by complex models. Finally, two simplified models to evaluate the resistance of confined masonry walls by considering the failure plane on the wall diagonal were developed. One supposes the masonry failure by shear effect and the other supposes the masonry failure by induced tension. The ratio theoretical resistance vs. experimental resistance was adequate for walls built from different materials and tested under different loads, which had ratio Height/Length ranging from 0.74 to 1.26

The loads applied to pile foundations installed offshore vary greatly from those encountered onshore, with more substantial lateral and torsional loads. For combined axial and lateral loading the current design practice involves applying an axial load to a deep foundation and assessing the pile behaviour and then considering a lateral load separately. For the problem of an altering directions of lateral loads (e.g. due to changes in the wind directions acting on offshore wind turbines) a clear design procedure is not available. There is thus a need for a clearly established methodology to effectively introduce the interaction between the four different loading directions (two lateral, one axial and one torsional). In this thesis, a model is presented that introduces a series of Winkler elasto-plastic elements coupled between the different directions via local interaction yield surfaces along the pile. The energy based method that is used allows the soil-pile system to be defined explicitly using two equations: the energy potential and the dissipation potential. One of the most interesting applications of this model is to piles subjected to a change in lateral loading direction, where the loading history can significantly influence the pile behaviour. This effect was verified by a series of experimental tests, undertaken using the Geotechnical Centrifuge at UWA. The same theory was then applied to cyclic loading in two dimensions, leading to some very useful conclusions regarding shakedown behaviour. A theoretically based relationship was applied to the local yielding behaviour for a pile subjected to a combination of lateral and axial loading, allowing predictions to be made of the influence of load inclination on the pile behaviour. The ability of this model to represent interaction between four degrees of freedom allows a more realistic approach to be taken to this problem than that considered in current design practice.

An integrated experimental and numerical research program investigating the elastic and inelastic performance as well as the kinematic behaviour of shearwalls with openings is presented in this study. The influence of the geometrical dimensions of the wall configurations and the mechanical properties and configurations of hold-downs on both elastic and inelastic behaviours including the possible kinematic modes of the shearwalls are investigated. The research also proposes the concept of equivalent-frame-model applicable for shearwalls where openings are cut-out from CLT panels. Are also presented, five racking tests performed on full scale CLT walls in order to validate the numerical models as well as the equivalent frame model. From review of the available literature emerges that for CLT shearwalls with openings, studies are not at the same level of abundance in research compared to walls without openings, due to the simple reason that SSW is generally a widespread technique. Thus, the kinematic behaviour and the coupling effect are inexistent and presented here. The investigations of the wall’s behaviour in the elastic and inelastic ranges demonstrate the important effect of the lintel and wall segment slenderness as well as the hold-down stiffness effect on the mechanical behaviour and the global kinematic behaviour as well. It is found that the kinematic modes can change when the walls are stressed beyond their elasticity limit. The failure mode and the global ductility are highly dependent on the hold-down configurations particularly for walls with door openings. The degree of coupling decrease with increased hold-down stiffness and the wall segment width. With regards to the equivalent frame model, a reasonable fit is found between the proposed EFM and a detailed 2D area element model when the global elastic stiffness and tensile load in the hold-down were compared. The model is successfully validated through five full-scale tests on CLT shearwalls with door or window opening as well as two published studies on walls with door openings. The EFM is capable of predicting the behaviour in the wall with reasonable accuracy, especially for walls whose behaviour was dominated by the hold-down behaviour.

No description available.

<p>Lateral loads on buildings, either caused by wind or seismic events, are resisted primarily by the in-plane strength and stiffness of the walls oriented parallel to the direction of the applied load. The concern associated with relying on unreinforced masonry (URM) shear walls to transfer the load to the foundation is that the typical modes of failure are characterized by brittle behaviour, with rapid decreases in capacity and very limited deformations once the ultimate load is reached.</p> <p>Traditional strengthening techniques have several undesirable properties, including being labour intensive and adding weight to the structure. Past research has shown that fibre reinforced polymer (FRP) reinforcement is an effective method of increasing both the strength and ductility of URM. One of the most desirable properties of FRP is that it has a high strength to weight ratio.</p> <p>An experimental investigation was conducted to study the influence of surfacebonded fibreglass laminates on the sliding shear resistance of URM. The investigation was conducted in three phases:</p> <p>1 Phase One: Analyzing the performance of five different test specimen shapes retrofitted with GFRP to determine the most adequate configuration for further shear slip tests. The data was also of direct use as an evaluation of strength and behaviour of FRP reinforced masonry subjected to shear-slip failure. Thirty-seven shear slip specimens were tested to failure. The average increase in shear strength ranged from 3 .1 to 7. 7 times that of the unretrofitted counterparts.</p> <p>2 Phase Two: Assessing the feasibility of obtaining two sets to data from each test specimen.</p> <p>3 Phase Three: Assessing the shear-slip strength and behaviour of URM reinforced with fibreglass mesh, of different weights, adhered at two different orientations to the bed joint slip planes (0°190°, ±45°) using a modified mortar parging. Twenty-one shear slip specimens were tested to failure. Typically, for any given mesh weight, orienting the fibres at ±45° resulted in failure characterized by higher strength and less ductility compared to tests with fibres oriented at 0°190° to the bed joints. At ±45° orientation, the fibres ruptured at failure. When the mesh was oriented at 0°190°, the fibres pulled out of the cement parging, which limited the strength, but enabled specimens to undergo large deformations while maintaining fairly constant residual capacity.</p> / Master of Engineering (ME)

Cette recherche propose des méthodes d’amélioration de résistance et d’évaluation du comportement de murs en maçonnerie confinée construits en briques solides d’argile cuite. Ces éléments sont largement utilisés dans la construction des bâtiments à l’État du Guerrero (Mexique) lesquels doivent résister charges séismiques importantes. Ainsi, un programme expérimental a été développé pour évaluer les propriétés mécaniques des briques et de la maçonnerie, qui sont nécessaires dans la conception et analyse des constructions. Pour augmenter la résistance de la maçonnerie et compenser la variabilité de la résistance à la compression des briques, un mortier à haute résistance et un renfort métallique dans les joints ont été utilisés. Certaines propriétés mécaniques sont égales à celles communément citées, cependant, les autres ont des valeurs deux fois plus grandes. Dans cette région du pays, les trois premiers tests de murs à échelle réelle construits en briques solides d’argile cuite ont été réalisés sous charge latérale alternée afin d'évaluer son comportement. Un renfort métallique et une couche du mortier ont été placés dans les surfaces de deux murs. Ceux-ci ont présenté un bon comportement et le renfort a eu un comportement structural adéquat. Avec les données expérimentales, plusieurs modèles numériques de panneaux et de murs ont été mis au point afin de reproduire l'enveloppe de résistance et le mode de défaillance. Ces modèles ont également évalué l'influence des propriétés mécaniques des briques et des joints sur le comportement global des spécimens. Aussi, un renfort métallique a été placé à l’intérieure des joints dans deux modèles. D'un autre côté, à partir de résultats expérimentaux obtenus et cités, une loi de comportement de la maçonnerie a été définie pour construire un modèle simple qui donne des résultats concordants à la fois avec les résultats expérimentaux et ceux obtenus par la méthode des éléments finis. Finalement, deux modèles simplifiés ont été proposés afin d’évaluer la résistance de murs en maçonnerie en supposant que le plan de rupture est suivant la diagonale du mur. L'un suppose la rupture de la maçonnerie par effet de cisaillement tandis que l'autre suppose la rupture par effet de tension induite. Le ratio entre résistance théorique et résistance expérimentale a été acceptable pour 27 murs faits de matériaux différents et testés sous différents types de chargement où le ratio hauteur sur longueur varie entre 0,7 et 1,26 / This research work proposes methods to rises the resistance and to evaluate the behavior of confined masonry walls built from clay solid bricks. These elements are widely used in Guerrero State (México) to build masonry structures, which should resist high lateral loads because of the serious seismic hazard. Therefore, a large experimental program to evaluate the mechanical properties of bricks and masonry currently required in the design process and masonry analysis was developed. To rises the masonry resistance and to counteract the influence of the compressive strength of the pieces on the masonry behavior, a high compressive strength mortar and a metallic reinforcement inside the joints were used. With respect to referenced values of the mechanical properties, some were similar and others were twice bigger. In this country zone, the first three tests under lateral load on full-scale confined masonry walls built from clay solid bricks were carried out in order to evaluate its behavior. A reinforcement composed by metallic hexagonal mesh-mortar coat was placed on the faces of two walls to rise or to restore the resistance. The walls showed good behavior and the reinforcement had adequate structural efficiency. Numerical models of panels and walls built by using the experimental data evaluated the envelope resistance, the failure mode and showed the influence of the mechanical properties of the pieces and joints on the global behavior. Two models had metallic reinforcement inside the joints. In addition, a constitutive law of the masonry defined from experimental results allowed to elaborate a simple model, which results were concordant with respect to the experimental results and similar to those calculated by complex models. Finally, two simplified models to evaluate the resistance of confined masonry walls by considering the failure plane on the wall diagonal were developed. One supposes the masonry failure by shear effect and the other supposes the masonry failure by induced tension. The ratio theoretical resistance vs. experimental resistance was adequate for walls built from different materials and tested under different loads, which had ratio Height/Length ranging from 0.74 to 1.26