Pedestrian bridges tend to become increasingly slender, exarcebating the bridge vibrations sensitivity under pedestrian walking forces. Engineers usually use tuned mass dampers (TMDs) to mitigate these vibrations and avoid pedestrian discomforts. During unusual events, TMDs can be not active. The aim of this paper is to investigate three simplified devices that can be quickly and temporarily installed to ensure comfort for unusual events. These devices act on the stiffness or the damping of the structure. Two proposed solutions presuppose the presence of water below the footbridge. The drag force is used to increase the damping of the footbridge. The third solution, which can be implemented without water, reduces the footbridge acceleration by increasing stiffness. The design of such devices is illustrated for the new Sofie Berthout footbridge in Mechelen, Belgium.