Identification of Bridge Movement Mechanisms

Bridge behavior is highly dependent upon the movement mechanisms present throughout the structure. These mechanisms (e.g. bearing, joints, etc.) have a substantial impact on the long-term durability and potential safety of the structure. A major distinguisher between the varieties of movement systems is their operating timescale. In some cases, they function rapidly, within fractions of a second, and in other cases gradually over days, months or even years. However, in nearly all cases, the lifecycle of the movement system is shorter than that of the bridge assuring the need for future intervention. Breakdown of a movement system can produce unintended forces/deformations that progressively degrade the structure. Identification and tracking of movement mechanisms proactively address long-term durability by helping to avoid these unintended consequences. A general framework for characterization of these mechanisms was developed. This framework was applied to an operating bridge that includes several critical mechanisms operating over different timescales. As a result of this and other studies, recommendations are provided for identification of bridge movement systems.