A time domain method for reconstruction of pedestrian induced loads on vibrating structures

• Published in: Mechanical systems and signal processing Vol. 171; p. 108887
• Main Authors: Firus, Andrei, Kemmler, Roman, Berthold, Hagen, Lorenzen, Steven, Schneider, Jens
• Format: Journal Article
• Language: English
• Published: Berlin Elsevier Ltd 15.05.2022; Elsevier BV
• Subjects: Acceleration; Biomechanics; Footbridges; Force plates; Force reconstruction; Ground reaction forces; Human induced vibrations; Human–structure interaction; Identification methods; Inverse problems; Load cells; Moving force identification; Noise levels; Optimization; Pedestrian bridges; Structural response; Time dependence; Time domain analysis; Vibration serviceability; Walking; Ground reaction forces; Vibration serviceability; Inverse problems; Human induced vibrations; Force reconstruction; Human–structure interaction; Footbridges; Moving force identification
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2022.108887

The present contribution proposes a novel method for the indirect measurement of the ground reaction forces (GRF) induced by a pedestrian during walking on a vibrating structure. Its main idea is to formulate and solve an inverse problem in the time domain with the aim of finding the optimal time dependent moving point force describing the GRF of a pedestrian (input data), which minimizes the difference between a set of computed and a set of measured structural responses (output data). The solution of the inverse problem is addressed by means of the gradient-based trust region optimization strategy. The moving force identification process uses output data from a set of acceleration and displacement time histories recorded at different locations on the structure. The practicability and the accuracy of the proposed GRF identification method is firstly evaluated using simulated measurements, which revealed a high accuracy, robustness and stability of the results in relation to high noise levels. Subsequently, a comprehensive experimental validation process using real measurement data recorded on the HUMVIB experimental footbridge on the campus of the Technical University of Darmstadt (Germany) was carried out. Besides the conventional sensors for the acquisition of structural responses, an array of biomechanical force plates as well as classical load cells at the supports were used for measurement reference GRFs needed in the experimental validation process. The results show that the proposed method delivers a very accurate estimation of the GRF induced by a subject during walking on the experimental structure. •Identification of ground reaction forces using measured dynamic structural responses•Analysis of human-structure interaction by means of identified ground reaction forces•Accurate identification of ground reaction forces based on a low number of sensors