A novel cable-pulley based self-centering energy dissipation (CP-SCED) brace for seismic induced damage mitigation of RC double-column bridge piers

An innovative cable-pulley based self-centering energy dissipation (CP-SCED) brace with adjustable hysteresis parameters is proposed in the present study. It is designed to control seismic induced damages to engineering structures, with the aim of balancing different damage indicators for the structure. The proposed CP-SCED brace consists of a self-centering system, an external friction energy dissipation system and a cable-pulley system. The corresponding purposes are to provide self-restoring force, dissipating energy, and adjusting post-yield stiffness, respectively. The overall configuration, working mechanism and restoring-force model of this brace are first introduced. A simplified specimen is designed, manufactured and tested to validate the analytical model. Parametric studies are conducted to explore the influences of the key brace parameters on the hysteretic performance. Subsequently, the brace is applied to an RC double-column bridge pier, and system-level parametric analyses are carried out to evaluate the roles of different brace design parameters. Based on which, optimal parameters are recommended and verified. Finally, a ‘partial self-centering’ CP-SCED brace, which allows for certain static residual deformation, is identified as suitable for achieving a reasonable balance between the peak and residual deformations of the structure. Compared to the bare pier, the average peak and residual drift ratios are reduced by 66.14 % and 91.55 %, respectively. Moreover, the average base shear force of bridge piers with the brace recommended in this study is 93.22 % of that of piers with traditional SCED braces.