A Review on Comfort of Pedestrian Bridges Under Human-Induced Vibrations and Tuned Mass Damper Control Technologies

With the development of urban infrastructure construction, while pedestrian bridges meet traffic functions the issue of their comfort has become a core consideration in structural design. This is because the long-span lightweight structures, with their large flexibility and low fundamental frequencies, are also vulnerable to human-induced vibrations. Pedestrian load modellings include the deterministic time-domain model, which is widely adopted in codes due to its simplicity, the random model that takes into account individual variability, and the frequency-domain model. The deterministic time-domain model has abundant parameter determination results and has become relatively mature, while the latter two, although more rigorous, have relatively lagging development. Numerous studies have shown that acceleration limits are the main indicators for comfort assessment. Vertical vibrations are controlled by amplitude constraints, while for the lateral vibrations the "lateral lock-in" that can cause dynamic instability needs to be evaluated with particular emphasis. When comfort exceeds an acceptable degree, a prevalent countermeasure is to attach a Tuned Mass Damper (TMD) or Multiple Tuned Mass Damper (MTMD) system to the structure-the latter demonstrates stronger robustness when dealing with random pedestrian loads.