Keywords: aluminium structure, human induced vibration, structural dynamics, structural damping, finite element method, walking load model, system identification, indirect methods.

During the last two decades the topic of human induced vibration has attracted a lot of attention among civil engineering practitioners and academics alike. Usually this type of problem may be encountered in pedestrian footbridges or floors of paperless offices. Slender designs are becoming increasingly popular, and as a consequence, the importance of paying attention to vibration serviceability also increases.

This paper resumes the results obtained from measurements taken at different points of an aluminium catwalk which is 6 m in length by 0.6 m in width. Measurements were carried out when subjecting the structure to different actions:

• Static test: a steel cylinder of 35 kg was placed in the middle of the catwalk
• Dynamic test: this test consists of exciting the structure with singles impulses
• Dynamic test: people walking on the catwalk

Identification of the mechanical properties of the structure is an achievement of the paper. Indirect methods were used to estimate properties including the support stiffness, the beam bending stiffness, the mass of the structure (using Rayleigh method and iterative matrix method), the natural frequency (using the time domain and frequency domain analysis) and the damping ratio (by calculating the logarithmic decrement).

Experimental results and numerical predictions [1,2] for the response of an aluminium catwalk subjected to walking loads have been compared. The damping of this light weight structure depends on the amplitude of vibration which complicates the tuning of a structural model. In the light of the results obtained it seems that the used walking load model is not appropriate as the predicted transient vibration values (TTVs) are much higher than the measured ones.

1

M. Feldmann, Ch. Heinemeyer, Chr. Butz, E. Caetano, A. Cunha, F. Galanti, A. Goldack, O. Hechler, S. Hicks, A. Keil, M. Lukic, R. Obiala, M. Schlaich, G. Sedlacek, A. Smith, P. Waarts, "Design of floor structures for human induced vibrations", EUR 24084 EN, 2009.

2

G. Sedlacek, Ch. Heinemeyer, Chr. Butz, B. Völling, "Vibration of Floors - Generalisation of Criteria for Floor Vibrations for industrial", 2004.

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