Análise de vibrações e avaliação do conforto humano de passarelas mistas (aço-concreto) submetidas a carregamentos induzidos por pedestres

Abstract

Considering recent technological and scientific advances, footbridge projects have been designed increasingly lighter and slender, causing a reduction in the values of the natural frequencies of these structures, causing an increase in the risk of resonance with reference to loads induced by pedestrians. Therefore, the objective of this research work is to investigate the dynamic structural behavior of composite footbridge (steel-concrete), when subjected to dynamic actions produced by pedestrians, keeping in mind the analysis methodologies existing in the technical literature. Throughout the text, traditional mathematical models used to characterize human action, expedient methods for dynamic analysis of footbridge are presented, in addition to the human comfort criteria established by current design standards. Furthermore, in this research work the dynamic structural response of footbridge is also investigated based on the use of biodynamic models, representative of pedestrians, in order to take into account the dynamic properties of individuals and the effect of the dynamic pedestrian-structure interaction. The analysis methodologies are applied to three structural projects of mixed footbridge (steel-concrete) with lenght of 27,2m, 32m and 36m, respectively, all located in the city of Rio de Janeiro/RJ, Brazil. The numerical modeling of the structures was developed based on the use of the ANSYS finite element program. Based on the results achieved, it was observed that the design standards and recommendations do not yet reflect advances in research on the topic and present conservative human comfort criteria. Otherwise, more recent analysis methodologies, such as the SÉTRA and HIVOSS design guides, have proven to be closer to the real behavior of footbridge. On the other hand, it is worth highlighting that traditional mathematical models of dynamic loading, and even the SÉTRA and HIVOSS design guides, produce superior dynamic responses (peak accelerations) when compared to those determined from the use of biodynamic models to simulate the induced dynamic actions. by pedestrians. In this way, it is clear that the use of biodynamic models is relevant for the final assessment of human comfort on pedestrian footbridge, in a more realistic way, and that there is still a significant demand regarding the development of research on this topic.