English Essay Example | Topics and Well Written Essays - 250 words

English - Essay Example The movement was caused by an unusual phenomenon, Synchronous Lateral Excitation (London Landmarks, 56). When people walk, they naturally sway a little, which in turn caused the bridge to sway with them. Given that the engineers had not installed any form of dampers, the swaying of the bridge was uncontrollable (BBC online, 2000). Synchronous lateral excitation is basically when the bridge moves laterally in conjunction with outside forces. In this case, pedestrians walking across the bridge. In order for the engineers to alleviate this movement, they needed to install a damping system. After discussion of either active or passive damping, they chose passive damping. This form of damping uses viscous dampers that are encased pistons, similar in action to the shocks of a vehicle, to absorb and transfer the movement of the bridge so that the swaying is no longer felt. These viscous dampers reduce the lateral motion. In order to reduce the vertical motion, the engineers employed tuned m ass dampers. These dampers are very simple in their technology, as they are tuned to the frequency of the inertia of the bridge, thus reducing lateral movement (Jones, 87). The engineers in this case should have taken a closer look at the mechanics of the bridge when they built it.