HSI effects on pedestrian bridges

Abstract: The study on Human Structure Interaction (HSI) effects represent a new research field in the design of pedestrian bridges. The presence of pedestrians on the structure affects the dynamic properties of the bridge, and these changes may be quantified in order to design pedestrian bridges in a more efficient way. The Dynamic Amplification Factor (DAF) curve shifts downward and towards the left when increasing number of pedestrians. The thesis, which is strictly connected to a journal paper to be submitted in 2021, includes a new formulation of the dynamic response through the DAF curves and an experimental campaign to verify the shift. A HSI model, based on Caprani continuous formulation, was created on MATLAB.To perform the experimental campaign, the Folke Bernadotte Bridge in Stockholm was chosen. The dynamic response due to a hammer test, was registered without pedestrians and with 35 pedestrians on the bridge. The dynamic properties of the bridge, such as natural frequencies, damping, mode-shapes, Frequency Response Function (FRF) are estimated in both cases. A Finite Element Model (FEM) is built on Abaqus, natural frequencies and mode-shapes are compared. Moreover, a running test is performed on the bridge and the single pedestrian loading is modelled as a moving harmonic. This test brings different values of stiffness and damping for the pedestrian to be compared to the values assumed in the HSI model for standing pedestrians.A quantification of the variation of the bridge properties due to Human structure interaction may lead to a new way to design pedestrian bridges considering pedestrians not only as loading sources of the structural system but also as dynamic vibration adsorbers (DVA).