Abstract Summary
The progressive incursion of increasingly resistant and lightweight materials in the construction industry added to the hypothesis of a global regeneration of urban structures based on new architectural and engineering requirements of greater technical and aesthetic demands, has generated that civil structures such as bleachers, stairs, slabs, and especially pedestrian bridges present a high susceptibility to excessive vibrations due to the action of dynamic loads, where the most frequent source of excitation is the one induced by human activity, especially human walking. These anthropic loads present adaptive phenomena, due to structural vibrations, generated by the coupling effects of the existing Human-Structure Interaction (HSI). In general, two main aspects are considered in the effects of HSI in this type of civil structures. The first one estimates change in the dynamic properties, due to the additional presence of a non-stationary mass on it. The second aspect refers to the degree of coupling between the people in transit, as well as between them and the structure. Although research on the effects of IHE has increased considerably in recent years, these aspects have not yet been fully detailed and addressed. Therefore, this research focused, firstly, on developing a Multiaxial Dynamic Platform called the Human-Structure Interaction Multiaxial Test Framework (HSI-MTF), with the objective of acquiring three-dimensional loads induced by human gait under the effects of lateral harmonic motions. Secondly, an experimental campaign was conducted with seven test subjects (TS) without motor impairment conditions, mass ranges of 64.0→80.0 kg and heights between 1.66→1.79 m; to whom, gait loads were acquired and evaluated under lateral sinusoidal movements, with displacements between 5.0→50 mm and a frequency content of 0.7→1.3 Hz. The lateral loads induced by human gait during the HSI-MTF flexible surface displacement protocols determined that for displacements less than 20.0 mm the gait frequency content remains predominant in combination with that induced by the HSI-MTF. However, for larger displacements the predominant frequencies in the loads are those induced by the HSI-MTF; furthermore, for load amplification factors values of up to 35.0% of the SP weight were reached for displacements on flexible surfaces, compared to an average of 5.0% for rigid surfaces. For vertical loads, of which there was no record in the literature under this condition, amplifications of up to 30.0% and relevant changes in their frequency content were calculated, in comparison with the walking loads on rigid surfaces.
