Excitation energy distribution of measured walking forces
Springer / Society for Experimental Mechanics
© The Society for Experimental Mechanics, Inc. 2017
Reason for embargo
Under indefinite embargo due to publisher policy.
For vibration serviceability of floors, current design guidelines propose different force models to represent human walking on structures. Those models have been derived based on many assumptions to simplify the real force induced by human walking. One of those assumptions states that the force is assumed periodic. Other simplification is that the spectrum of the force is assumed to have very low energy beyond a certain frequency limit, hence it can be neglected in that higher frequency region. Those assumptions have been verified and validated over time for conventional floor structures. However, modern floors are slender, made of lightweight materials, and have strong orthotropic properties and low point stiffness. Hence they feature localized higher modes that could be excited even with small amount of energy. In this paper, real walking forces are used to demonstrate the excitation energy distribution over frequency range of 0–60 Hz. A unique database of 852 vertical continuous ground reaction forces (GRF) measured on an instrumented treadmill due to walking is used for that purpose. Excitation energy is calculated by summing the power of the measured force in the frequency domain. It is found that there are considerable amounts of excitation energy well beyond the frequency limits proposed by the current floor design procedures. Boxplots are presented showing the realistic energy distribution which could excite the higher modes of lightweight and slender floors.
The database of walking forces was created courtesy of funding by the UK Engineering and Physical Sciences Research Council, Grant EP/E018734/1 (Human walking and running forces: novel experimental characterization and application in civil engineering dynamics). The paper was prepared with the support of the Engineering and Physical Sciences Research Council (EPSRC) grant reference EP/G061130/1 (Dynamic Performance of Large Civil Engineering Structures: An Integrated Approach to Management, Design and Assessment) for which the writers are grateful. The financial support of The Higher Committee for Education Development in Iraq (HCED IRAQ scholarship reference GD-13-5) is highly appreciated as well.
Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)
This is the author accepted manuscript. The final version is available from the Springer via the DOI in this record
Dynamics of Civil Structures, Volume 2: Proceedings of IMAC-XXXV,: 35th International Modal Analysis Conference, 30 January - 2 February 2017, Garden Grove, California, USA, pp. 347-351