<p>This thesis is focused on modeling of progressive failure in brick masonry structures. Two distinct strategies are examined, namely meso-modeling and macromodeling approach.</p> <p>In the first part, an advanced constitutive model capable of addressing both pre and post-localization behavior is developed and implemented in a commercial finite element package. A mesoscopic modeling approach is then adopted, in which the structural behavior is examined at the level of constituents, i.e. brick and mortar. The performance of the model is verified by simulating a series of experimental tests reported in the literature. Those include the tests conducted by van der Pluijm (1993), Atkinson et al. (1989), and Page (1983).</p> <p>Later, an alternative approach is developed, based on theory of homogenization, in which a lower bound assessment is employed to predict the directional strength characteristics of the brick masonry. The performance of the model is verified using numerical homogenization which involves a finite element analysis of a periodic unit cell. For both these approaches, the failure envelopes for brick masonry at different orientations of the bed joints are obtained.</p> <p>Finally, a methodology is proposed for a systematic identification of material parameters of a macroscopic failure criterion describing the anisotropic strength characteristics of the brick masonry. This criterion is formulated in the framework of Critical Plane Approach (CPA) and its performance is verified against the experimental data of Page (1981 and 1983).</p> / Doctor of Philosophy (PhD)

<p> A Matrix Stiffness-Modification Technique has been proposed for the inelastic analysis of ·reinforced concrete frames subjected to short term or sustained loads. To check the applicability of the analytical method, two large scale concrete frames were tested under short-term loads and sustained-loads respectively. In addition, data for twenty-two frame tests from other sources has also been compared with the non-linear analysis. Close agreement has. been observed for all the frames considered. It was further concluded that a conventional elastic matrix method using stiffnesses based on a cracked transformed section of concrete does net yield accurate results, especially in the case of sustained loading conditions. From the method developed, comments can therefore be made on present column design practice. </p> / Thesis / Master of Engineering (MEngr)

The objective of this research program is to further evaluate the performance and constructability of reinforced concrete (RC) column-steel beam-slab systems (RCS) for use in low- to mid-rise space frame buildings located in regions of high wind loads and/or moderate seismicity. To better understand these systems, two full scale RCS cruciform specimens were tested under bidirectional quasi-static reversed cyclic loading. The experimental portion of this research program included the construction and testing of two full-scale cruciform specimens with identical overall dimensions but with different joint detailing. The two joint details evaluated were joint cover plates and face bearing plates with localized transverse ties. The construction process was recorded in detail and related to actual field construction practices. The specimens were tested experimentally in quasi-static reversed cyclic loading in both orthogonal loading directions while a constant axial force was applied to the column, to simulate the wind loads in a subassembly of a prototype building. To compliment the experimental work, nonlinear analyses were performed to evaluate the specimen strength and hysteretic degradation parameters for RCS systems. In addition, current recommendations in the literature on the design of RCS joints were used to estimate specimen joint strength and were compared with the experimental findings.

The objective of this research program is to further evaluate the performance and constructability of reinforced concrete (RC) column-steel beam-slab systems (RCS) for use in low- to mid-rise space frame buildings located in regions of high wind loads and/or moderate seismicity. To better understand these systems, two full scale RCS cruciform specimens were tested under bidirectional quasi-static reversed cyclic loading. The experimental portion of this research program included the construction and testing of two full-scale cruciform specimens with identical overall dimensions but with different joint detailing. The two joint details evaluated were joint cover plates and face bearing plates with localized transverse ties. The construction process was recorded in detail and related to actual field construction practices. The specimens were tested experimentally in quasi-static reversed cyclic loading in both orthogonal loading directions while a constant axial force was applied to the column, to simulate the wind loads in a subassembly of a prototype building. To compliment the experimental work, nonlinear analyses were performed to evaluate the specimen strength and hysteretic degradation parameters for RCS systems. In addition, current recommendations in the literature on the design of RCS joints were used to estimate specimen joint strength and were compared with the experimental findings.

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.