Prediction and Control of Pedestrian-Induced Vibration in Footbridges

Abstract

Footbridges vibrate because the forces imparted by the user are applied with the frequency of the pace and movement, however small, is therefore a forced vibration. In instances where the pace coincides with a structure resonant frequency dynamic movement can be quite large and the user may be disturbed or even alarmed. Vibration is recognized as a serviceability limit state and a process that can be employed as a design tool permitting an early assessment of behavior is proposed. The subject is investigated in terms of the pedestrian excitation source, the structure response, and acceptance criteria. Calculated response compares favorably with test results. Remedial or preventative options in the form of various damping devices are reviewed.