A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription.For more information, please contact the WRAP Team at: wrap@warwick.ac.uk This paper has been published under the following reference: Ahmadi, E., Vertical ground reaction forces on rigid and vibrating surfaces for vibration serviceability assessment of structures.
Abstract 10Lightweight structures are sensitive to dynamic force generated by human walking and 11 consequently can exhibit excessive vibration responses. The imparted forces, known as 12 ground reaction forces (GRFs), are a key input in the vibration serviceability assessment of 13 footbridges. Most GRF measurements have been conducted on rigid surfaces such as 14 instrumented treadmills and force plates mounted on strong floors. However, it is thought that 15 the vibrating surface of a footbridge might affect the imparted human force. This paper 16 introduces a unique laboratory experimental setup to investigate vertical GRFs on both rigid 17 surface (strong floor) and a higher frequency flexible surface (footbridge). 810 walking trials 18were performed by 18 test subjects walking at different pacing frequencies. For each trial, test 19 subjects travelled a circuit of a vibrating footbridge surface followed by a rigid surface. A 20 novel data collection setup was adopted to record the vertical component of GRFs, and the 21 footbridge vibration response during each trial. Frequency-domain analysis of both single-22 step and continuous GRFs was then performed. The results show that the footbridge vibration 23 affects GRFs, and changes GRF magnitudes for harmonics in resonance with the footbridge 24 vibration (up to around 30% reduction in the dynamic load factor of the third harmonic). This 25 This paper has been published under the following reference: Ahmadi, E., Caprani, C., Živanović, S. and Heidarpour, A. (2018) Vertical ground reaction forces on rigid and vibrating surfaces for vibration serviceability assessment of structures. Engineering Structures, Vol. 172, pp. 723-738. (https://doi.org/10.1016/j.engstruct.2018 2 finding, and the measured GRFs, can be used for more accurate vibration serviceability 26 assessments of existing and new footbridges. 27
