Abstract Static and dynamic effects on power transmission towers can be evaluated by methodologies available in codes, which suggest the use of linear static analysis. By using numerical simulations, it is possible to observe the strong influence of the geometric nonlinear behavior of transmission cables. Dynamic effects also strongly influence this behavior, with the possibility of resonance between the cables and the structure, but up to the moment, the existent analysis procedures have not been completely validated on an experimental basis. In order to validate a complete analysis methodology, experimental procedures are proposed for a suspension tower of a 138kV transmission line in use. A tridimensional anemometer was installed on this structure in order to measure the values and directions of wind speeds. Simultaneous strain values were collected on the main elements of the tower through optical extensometers. Optical sensor technology with Fiber Bragg Gratings was used, due to the characteristic of immunity to the electromagnetic field occasioned by high electric currents. The string swing angle was evaluated through a high-resolution camera and a tridimensional accelerometer. With this instrumentation, it is possible to create a complete database that correlates wind speeds with the responses of the structural set. At the moment, 5 months of data have been collected and the instrumentation is in the final testing phase and synchronized. After this step, real-time measurements will be performed.

Um conector de cisalhamento desenvolvido na UFMG, para uma viga mista de aço-concreto, composta por um perfil metálico de parede fina, apresentou comportamento muito mais flexível do que um conector convencional soldado. Devido a essa flexibilidade, o papel desempenhado pelo atrito na interface do perfil metálico com a laje de concreto pode se tornar relevante sob certas condições, tanto para os estados- limites de serviço como para os estados-limites últimos. As disposições normativas brasileiras e norte-americanas ainda não reconhecem a contribuição do atrito no comportamento de vigas mistas, apesar de reconhecerem essa contribuição em lajes mistas. Este trabalho apresenta os testes experimentais realizados com e sem a presença de atrito em vigas mistas simplesmente apoiadas com conectores flexíveis e os modelos numéricos desenvolvidos para simular o comportamento dessas vigas. Os resultados experimentais mostraram acréscimos significativos da resistência e da rigidez das vigas devidos à presença do atrito na interface concreto-aço. As comparações entre resultados experimentais e teórico-numéricos em termos de deslocamentos verticais para cargas crescentes mostraram boas correlações.

A shear connector, developed to be applied to a composite beam whose steel profile is a thin-walled box profile, displayed much greater flexibility than the conventional welded shear connector, leading to particular issues in the composite beam behaviour. One of these issues is the role played by friction at the interface between the steel profile and the slab which, under particular circumstances, may be relevant for serviceability limit states and also for ultimate limit states. The Brazilian and American Standards do not yet recognize the friction contribution in the behaviour of composite beams, though they recognize this contribution in composite slabs. This paper presents the experimental tests carried out with and without friction contribution on simple supported composite beams with flexible connectors and the numerical models developed to simulate the behaviour of the tested beams. The experimental tests revealed significant increases in strength and stiffness of the composite beam due to friction contribution and the comparisons between numerical and experimental results displayed good correlations.