Mitigation of human-induced vibrations in suspension footbridges via multiple tuned mass dampers

The dynamic response of suspension footbridges to pedestrian-induced excitations and its passive mitigation are investigated. The linearized equations of motion are obtained from a nonlinear model and the Gal¨erkin discretization approach is employed to solve both the free and forced elastodynamic problems. First, the leading characteristics of the Singapore Suspension Foobridge, whose lowest two modes possess closely-spaced frequencies near the so-called crossover condition, are outlined. Further it is shown the effectiveness of the multiple tuned mass dampers (TMD) architecture. To this end, the frequency-response functions as well as direct integration of the equations of motion are employed to predict the response of the footbridge by itself and with the addition of the TMDs under various scenarios of pedestrian excitation, namely, walking, running and jumping.