Avaliação da influência dos efeitos térmicos nas deformações em elementos estruturais

Abstract

This work aims to complement and deepen knowledge regarding the evaluation of the influence of thermal and environmental actions on the deformations observed in structural elements. A common problem faced in the structural monitoring of these elements is the distinction between the values of deformation obtained in the instrumented element due to the change in temperature, the values of deformation from other actions, including the small amount of available material that addresses the problem. Nowadays, with the increasing tendency to elaborate works of art, in particular bridges, bridges and viaducts, more and more daring, making use of structures with complex geometries, with the need to conquer increasingly longer spans and under climatic conditions which interfere directly in the in-service performance of the structural elements, studies of the thermal interference in the behavior of the structure are necessary, for the proper quantification of these effects. For this purpose, the deformation levels were identified and distinguished in pre-instrumented structures and in particular loading regimes, both mechanically and thermally. The treatment of the data of deformation was carried out through techniques of signal treatment, as well as statistical analysis. The structural elements covered in this work compose parts of bridges executed in both reinforced concrete and steel. In order to validate the proposal, laboratory tests were carried out with a prismatic test specimen subjected to constant mechanical load and the ambient thermal variation. We used the wavelet transform and the statistical correlation in the data treatment, in order to interpret the observed deformation levels and eliminate inherent noise. The best results were found using the Daubechies motherwidths and these were satisfactory, obtaining after the statistical analysis through the Wilcoxon paired test, the validation of the proposed methodology. Through the results of the tests, it can be stated that the deformation portion of thermal origin corresponds to approximately 40% of the total deformations measured.