This research work studies the fundamentals of the Hybrid Frequency-Time Domain (HFTD) method for dynamic analysis of structures, applied to the seismic analysis of dam-reservoir interaction systems. The theoretical consistency and accuracy of the HFTD method, based on the frequency domain Fourier analysis, is demonstrated through all the parts of the thesis, but particularly in Chapter 5 for linear and highly non-linear single degree of freedom (SDOF) models subject to several types of loading, and in Chapter 7 for a 2D dam-reservoir interaction finite element model subject to an earthquake ground acceleration loading. On the other hand, a Finite Element Method (FEM) formulation of dam-reservoir interaction problems is presented, being demonstrated the frequency-dependence nature of this type of systems. The fluid compressibility and boundary conditions of the reservoir are analytically...

Throughout this thesis, advanced numerical tools and laboratory tests are investigated that will allow an accurate prediction of the global nonlinear structural response of hybrid timber-steel connections under cyclic loading. The conceptual development of the model, its mathematical formulation, numerical coding and implementation in a commercial FE software are documented in this thesis. Furthermore, the proposed timber material model has been developed within the framework of the Continuum Damage Mechanics (CDM) theory, making it ideal for damage evolution modelling and behaviour-based seismic assessment of timber structures. Experimental studies available in the literature were employed to assess the accuracy and overall performance of the proposed constitutive model at the material and structural (or component) level. Additional local responses not easily identifiable from the exper...