Development of a novel rocking connection for tubular steel bridge piers: A proof of concept study

This paper introduces a novel pocket-type dissipative rocking connection for self-centering tubular steel bridge piers. Unlike typical self-centering systems, this connection does not utilize post-tensioned tendons and relies solely on gravity load for re-centering, but it employs a redundant mechanism to prevent geometrical instability and collapse. The connection consists of several components, including an embedded sleeve component and a ring plate bearing against the column and frictionally connected to the embedded component. During rocking, the ring plate provides two-level energy dissipation through friction and material yielding. In this connection, any residual drift could be easily recovered by untightening bolts in the frictional connection of the ring plate. A finite element model with contact elements at surface interfaces between different components was developed to simulate the response of the connection under vertical and lateral loading. Finite element analyses and quasi-static cyclic tests of a quarter-scale specimen demonstrated that the connection could provide adequate lateral resistance and a flag-shaped hysteresis response with marginal or recoverable residual displacements. Test results confirmed that the connection can sustain large lateral drifts (up to 7.6%) without structural damage. Test results also indicated that the hysteresis characteristics of the connection are highly influenced by the type and configuration of the washers in the bolt assembly of the frictional connection. The lateral strength and energy dissipation properties of the connection were greatly improved when conical spring washers were added to the bolt assembly.