No abstract

Observation of human‐induced large‐amplitude lateral vibration of an actual pedestrian bridge in an extremely congested condition is reported. Walking motions of pedestrians recorded by a video camera are analysed. It is found that walking among 20 per cent or more of the pedestrians on the bridge was synchronized to the girder lateral vibration. With this synchronization, the total lateral force from the pedestrians to the girder is evidently increased and it acts as a resonant force on the girder lateral vibration.

A new kind of passive mechanical damper, tuned liquid damper (TLD). is studied that relies upon the motion of shallow liquid in a rigid tank for changing the dynamic characteristics of a structure and dissipating its vibration energy. A nonlinear model of two-dimensional liquid motion inside a rectangular TLD subjected to horizontal motion is developed on the basis of shallow-water wave theory, where the damping of the liquid motion is included semianalytically. Using the model, the response of a structure with TLD is also computed. The liquid motion inside the TLD under harmonic base excitation and, furthermore, the response of a single-degree-of-freedom structure with TLD, subjected to harmonic external force, are experimentally investigated. The agreement is good between the experiment and the prediction.