Frequency Based Design of KDamper for Seismic Isolation of a Single Pier Concrete Bridge

Contemporary seismic isolation systems for bridge applications provide a) horizontal isolation from earthquake shaking effects, and b) energy dissipation mechanisms to reduce displacements. Throughout the years, many kinds of seismic isolation mechanisms have been developed, with those incorporating negative stiffness elements being the most promising ones. The negative stiffness behaviour is achieved through special mechanical designs involving conventional positive stiffness pre-stressed elastic mechanical elements, arranged in appropriate geometrical configurations. In this context, a novel passive vibration isolation and damping concept is introduced, the KDamper, whose main advantage is that no reduction in the overall stiffness of the system is required. In this paper, the application of the KDamper concept on a typical concrete bridge with conventional bearings, to mitigate seismic effects, is considered. The system’s design is based on frequency domain analysis of both the initial and the isolated bridge structure. Comparative results between the two systems confirm that the proposed device can provide a promising alternative to conventional techniques, offering numerous advantages, such as increased damping and simple technological implementations.