Typically, bridge structural systems are affected by random loads that can cause significant damage. One challenging problem in this field is the high-stress amplitude associated with distortion-induced fatigue. In this study, the hot-spot method and the master S-N curve method were validated for the evaluation of fatigue resistance induced by distortion in welded joints of steel bridges. Validation of the master S-N curve method in this research was a necessary prior step for application of the method in real case studies of road bridges, which will be subject to loads of variable amplitudes in the near future, ensuring the basis for the application. The method of validation was based on an important available full-scale fatigue test database, which was generated decades ago to serve as the foundation for the assessment of distortion-induced fatigue. Modelling was carried out based on the finite element method with the aid of ANSYS software, considering the shell and solid elements and equivalent structural stresses. The experimental results were compared with the numerical ones obtained with the two methodologies, and the difference, in terms of global and local tension, was less than 1%.

Highway bridges are usually subjected to random dynamic actions of variable magnitude due to vehicles convoys crossing on the bridge pavement deck along their service life. In this context, the asphalt pavement deteriorated road surface condition represents a key issue to assess the bridge displacement and stress values. This way, this research work aims to develop an analysis methodology in order to assess the dynamic structural behaviour of steel-concrete composite highway bridges including the vehicles convoys dynamic actions and the pavement progressive deterioration effect. The conclusions of this investigation have indicated that the displacements and stresses values are considerably higher, with relevant amplifications up to four times, when the road pavement deterioration effect is considered in the bridge dynamic analysis.

Com o objetivo de dar um outro uso às plataformas offshore fixa com o tempo de vida útil vencidas, principalmente aquelas situadas em campos com condições ambientais favoráveis para instalação de turbinas eólicas offshore, o presente trabalho de pesquisa ressalta a importância de avaliar a possibilidade de reutilização de uma plataforma (jaqueta) submetida ao carregamento de uma torres de 10 MW, considerando sobre tudo as novas condições de operação. Para isso se tem em conta as análises dos elementos que conformam a estrutura (jaqueta) de modos a atinar as suas respetivas razões de tensões. Considerou-se o carregamento da torre eólica de maneira pontualmente distribuído sobre os 4 nós no topo das pernas principais da jaqueta.  A estrutura investigada apresenta uma jaqueta de 16,85 m de altura, com a área da mesa inferior de 9,95 m x 9,95 m e 6,75 m x 6,75 m na mesa superior. O sistema estrutural foi desenvolvido com base à utilização do software OrcaFlex V10.3, que permite analisar as razões de tensões (“Unity Check”) incluído os efeitos de segunda ordem por meio da utilização do Método dos Elementos Finitos (MEF). Desta forma, os resultados obtidos ao longo das análises para avaliar o comportamento estrutural apontam para o fato de que a jaqueta investigada não atende aos critérios de projeto para dar suporte a torres eólicas de 10 MW.

The remarkable design and construction of constructions in large cities of optimization of engineering methods have as structural models in the increasingly high structural structures and/or stimuli, with low resistance and damping, transforming them into high structures in the increasingly structural structures. Powered by the action of the wind. Thus, it becomes rigorously necessary to study the possible constructions of the buildings in question, mainly as dynamic actions in the most realistic way as their non-deterministic properties. Furthermore, it is important to highlight, no less importantly, the study of the way of individual interaction, considering its influence on the resistance of the (global) structural system. Therefore, the conduct aims to analyze the present with wind action insurance contracts based on human comfort criteria. For the study in question, two “tall” buildings were considered, including the mixed structures (steel-concrete) and the other reinforced concrete structures. The first has a total height of 173 m with 48 floors, with a maximum dimension in the plan of 45 x 32 m. The second has a total height of 140 m with 40 floors, with a maximum dimension in the plan of 9 x 29 m. With the results obtained, it was noticed the reduction of the modelling process, as it significantly increased the reduction of the natural frequencies of the soil interactions of the buildings and accelerations, as it favored the increase of the reduction of the natural frequencies of the interactions of the buildings and the longitudinal buildings and transversal buildings.