Although branch plate connections with circular hollow section (CHS) members are simple to fabricate and cost-effective, they are generally very flexible under low load application resulting in the limit states design resistance being governed by an imposed deformation limit. Restricting the ultimate capacity of a branch plate connection by a deformation limit results in the inherent strength of the CHS member being under-utilized, highlighting the need to develop connection stiffening methods. Two methods to stiffen branch plate-to-CHS connections are examined: a through plate connection and a grout-filled CHS branch plate connection. Further, the current design guidelines of various plate-to-CHS connection types are reexamined including the effect of chord axial stress and chord length on connection behaviour. Finally, the behaviour of connections with non-orthogonal or skew plate orientation, which has not previously been examined, was studied in depth.The behaviour of these uniplanar connection types under quasi-static axial loading was studied through 16 large-scale laboratory experiments and 682 numerical finite element analyses, as well as an extensive review of all previous international experimental and numerical findings. The extensive study formed the basis for a complete set of proposed design guidelines and provided insight into plate-to-CHS connection behaviour. For all plate-to-CHS connection types, the plate thickness is shown to effect connection capacity, though previously this was thought not to have significant impact on connection behaviour. The existing ideology of using the same design recommendations for tension- and compression-loaded connections, which was developed from compression results, under-utilizes an inherent increase in capacity provided by a connection primarily loaded in tension. As such, the recommended design guidelines split the two load senses into separate expressions that reflect the difference in behaviour. Stiffened through plate connection behaviour was determined to be the summation of branch plate behaviour in compression and tension, leading to a significant increase in capacity and identical behaviour regardless of branch load sense. The skewed branch plate connection behaviour was found to relate directly to the established behaviour of longitudinal and transverse plate connections. A design function was developed that interpolates the capacities of intermediate angles by using the proposed design recommendations of the two extreme connection types. Finally, the examination of chord axial stress and chord length for plate-to-CHS connections yielded results similar to previous international studies on CHS-to-CHS connections. The effect of chord length, however, has wide-reaching implications as to how experimental and numerical FE research programs are developed.

This thesis deals with the use of the electronic measuring systems for monitoring structures. The first part of this work is focused on mapping the available measuring systems for monitoring deformations and strains, from the point of their measurement accuracy, the real advantages and disadvantages, including examples of monitoring of constructions. In the second part were selected measuring systems for monitoring strains and deflection interest structure. Subsequently, the measuring system with online recording into the tested roof structure was installed and the loading test was performed. Obtained data were compared with other two independent measurements. In the last part of the thesis, the measured values of each independent measurements were compared together, and with the values calculated from the mathematical model. The achieved results show that the installed monitoring system is capable to reliably measure deformation of the structure in real time and thus to warn the building administrator against the potential danger in advance.

The research presented in this work addresses open questions regarding (i) the fundamental understanding of powder compaction, and (ii) the complex mechanical response of particle-binder composites under large deformations. This work thus benefits a broad range of industries, from the pharmaceutical industry and its recent efforts on continuous manufacturing of solid tablets, to the defense and energy industries and the recurrent need to predict the performance of energetic materials. Powder compacts and particle-binder composites are essentially confined particulate systems with significant heterogeneity at the meso (particle) scale. While particle mechanics strategies for modeling evolution of mesoscale microstructure during powder compaction depend on the employed contact formulation to accurately predict macroscopic quantities like punch and die wall pressures, modeling of highly nonlinear, strain-path dependent macroscopic response without a distinctive yield surface, typical of particle-binder composites, requires proper constitutive modeling of these complex deformation mechanisms. Moreover, continued loading of particle-binder composites over their operational life may introduce significant undesirable changes to their microstructure and mechanical properties. These challenges are addressed with a combined effort on theoretical, modeling and experimental fronts, namely, (a) novel contact formulations for elasto-plastic particles under high levels of confinement, (b) a multi-scale experimental procedure for assessing changes in microstructure and mechanical behavior of particle-binder composites due to cyclic loading and time-recovery, and (c) a finite strain nonlinear elastic, endochronic plastic constitutive formulation for particle-binder composites.

This diploma thesis is concerned with the numerical analysis of welded aluminim structures. In these structures, there are significant decreases in the mechanical properties at the area of the weld and in the heat affected zone as a result of welding. Within this thesis, simulations of quasi-statically loaded welded joints made from EN AW-6082 T6 alloy were performed to investigate the load capacity and ductility of these joints. Computations were performed using a programme system based on an explicit finite element method. To describe material anisotrophy, a nonlinear material model called the Weak texture model was chosen. Material properties of the weld and the heat affected zone were considered to be different from base material. The required material parameters were adopted from available literature, however, material tests and indetification procedure of these parameters were described. In comparison with the experimental data, the results of the numerical simulations showed a relatively good ability of models to capture load capacity of studied welded joints. Nevertheless, due to mesh sensitivity of models caused by localization of deformation, it was not possible to determine ductility of these joints.

Diploma thesis is focused on the description of the parameters of nonlinear material models of concrete, which are implemented in a computational system LS-DYNA, interacting with performance of nonlinear test calculations in system LS-DYNA on selected problems, which are formed mainly by simulations of tests of mechanical and physical properties of concrete in uniaxial compressive and tensile on cylinders with applying different boundary conditions and by simulation of bending slab, with subsequent comparison of some results of test calculations with results of the experiment. The thesis includes creation of appropriate geometric models of selected problems, meshing of these geometric models, description of parameters and application of nonlinear material models of concrete on selected problems, application of loads and boundary conditions on selected problems and performance of nonlinear calculations in a computational system LS-DYNA. Evaluation of results is made on the basis of stress-strain diagrams and load-displacement diagrams based on nonlinear calculations taking into account strain rate effects and on the basis of hysteresis curves based on nonlinear calculations in case of application of cyclic loading on selected problems. Verification of nonlinear material models of concrete is made on the basis of comparison of some results of test calculations with results obtained from the experiment.