DYNAMIC LOAD FROM PEDESTRIAN FOOTSTEPS

摘要

The performance of pedestrian footbridge under environmental and pedestrian excitation has received much attention lately with the problem of resonating vibration of the Millennium Bridge in London. The dead weight of the bridge is small with increased improvement in the design method and the use of light-weight and high strength materials. Damping mechanism is seldom provided for this type of structure. This gives rise to unacceptable vibration from human or environmental excitations and causes alarm. This paper studies the vertical dynamic load generated by pedestrian footsteps on a simply supported steel bridge deck. The forces are identified using an existing algorithm on moving force identification developed by the author (Law and Fang, 2001). The identified footstep force is then generalized using a time series and the coefficients of which are obtained from collected samples of footstep forces. Further analysis on the samples collected is in process, and results would be useful for dynamic design of the performances of the pedestrian footbridge.