Abstract Summary
Current design methods for vibration serviceability assessment of pedestrian structures are generally based on footfall loading models representing walking over rigid level surfaces rather than oscillating surfaces that might affect the walking pattern. It is largely unknown how footstep forces would be modified due to human-structure dynamic interaction (HSI) if the walking surfaces are vibrating in vertical direction. A two-year project was carried out to identify vertical vibration conditions under which the human-structure interaction occurs. Part of the testing program was conducted on an outdoor footbridge. During the tests, participants walked over either the footbridge or a rigid ground surface at slow, normal and fast pacing frequencies. Ground reaction forces were measured by using insole sensors. The influence of vibration amplitudes and frequency ratios between walking and structural vibration were examined. Comparison of dynamic load factors (DLFs) of footfall loadings on the vibrating footbridge with those on the rigid overground was used to reveal force changes due to HSI. In addition, other parameters such as pacing frequency were also examined. The ultimate goal is to estimate the likelihood of the HSI occurring in any new structure and enable calculation of the vibration response in those cases when the HSI exists.
