Abstract: A friction damper comprises a channel member including at least one friction channel and a wedge member including at least one friction wedge received by a corresponding friction channel for sliding motion along the channel relative to the channel member. Each friction channel has a pair of internal sidewalls connected by an internal transverse wall, wherein at least one of the pair of sidewalls forms an obtuse angle with the transverse wall. In a preferred construction, the sidewalls are symmetrically convergent as they approach the connecting transverse wall. Each friction wedge includes a pair of external sidewalls parallel to the internal sidewalls of the channel, wherein the external sidewalls of the friction wedge are movable into surface-to-surface engagement with the internal sidewalls of the friction channel by adjusting the depth of receipt of the friction wedge in the friction channel.

Abstract: A seismic isolation bearing comprises a lower plate, an upper plate, and a cylindrical roller in rolling contact with an upwardly facing, bearing surface of the lower plate and a downwardly facing surface of the upper plate. The lower plate is fixable to a base, while the upper plate is fixable to a superstructure. One or both bearing surfaces are sloped to form a central trough at which the cylindrical roller resides under normal weight of the superstructure, and toward which the roller is biased when displacement between the plates occurs. A pair of sidewall members are fixed to the lower plate to withstand strong forces directed laterally with respect to the isolation axis along which rolling displacement occurs, and a pair of sliding guides carried one at each end of the roller provide dry frictional damping as they engage an inner wall surface of a corresponding sidewall member.

Abstract: A seismic isolation bearing comprises a lower plate, an upper plate, and a cylindrical roller in rolling contact with an upwardly facing bearing surface of the lower plate and a downwardly facing surface of the upper plate. The lower plate is fixable to a base, while the upper plate is fixable to a superstructure, for example a bridge deck. One or both bearing surfaces are sloped to form a central trough at which the cylindrical roller resides under normal weight of the superstructure, and toward which the roller is biased when relative displacement between the lower and upper plates occurs to provide a constant restoring force. A pair of sidewall members are fixed to the lower plate to withstand strong forces directed laterally with respect to the isolation axis along which rolling displacement occurs, and a pair of sliding guides carried one at each end of the roller provide dry frictional damping as they engage an inner wall surface of a corresponding sidewall member.

Abstract: A friction damper comprises a channel member including at least one friction channel and a wedge member including at least one friction wedge received by a corresponding friction channel for sliding motion along the channel relative to the channel member. Each friction channel has a pair of internal sidewalls connected by an internal transverse wall, wherein at least one of the pair of sidewalls forms an obtuse angle with the transverse wall. In a preferred construction, the sidewalls are symmetrically convergent as they approach the connecting transverse wall. Each friction wedge includes a pair of external sidewalls parallel to the internal sidewalls of the channel, wherein the external sidewalls of the friction wedge are movable into surface-to-surface engagement with the internal sidewalls of the friction channel by adjusting the depth of receipt of the friction wedge in the friction channel.

Abstract: A seismic isolation bearing comprises a lower plate, an upper plate, and a cylindrical roller in rolling contact with an upwardly facing bearing surface of the lower plate and a downwardly facing surface of the upper plate. The lower plate is fixable to a base, while the upper plate is fixable to a superstructure, for example a bridge deck. One or both bearing surfaces are sloped to form a central trough at which the cylindrical roller resides under normal weight of the superstructure, and toward which the roller is biased when relative displacement between the lower and upper plates occurs to provide a constant restoring force. A pair of sidewall members are fixed to the lower plate to withstand strong forces directed laterally with respect to the isolation axis along which rolling displacement occurs, and a pair of sliding guides carried one at each end of the roller provide dry frictional damping as they engage an inner wall surface of a corresponding sidewall member.