Test and analysis on a novel self-restoring uplift column

A novel self-restoring uplift column was proposed to allow uplift of exterior column bases of core-outrigger structures, which may make upper structure rock and hence mitigate seismic damage. The self-restoring uplift column consists of two steel sub-columns, a steel shear panel and several post-tensioned strands. Besides uplift mechanism, energy dissipating and self-restoring mechanisms were involved to dissipate energy and reduce structural residual drift, respectively. Low cycle test of four one-seventh scaled specimens were conducted and then simulated by finite element analysis. Self-restoring capability and satisfactory energy dissipating ability were observed in experimental results. The calibrated finite element models were then used to explore key design issues of the self-restoring uplift column. It was indicated that the elastic state of post-tensioned strands and sufficient restoring force were the two main factors influencing the restoring behavior most. A simplified model for axial behavior of the self-restoring uplift column was developed to simplify the design of the self-restoring uplift column. Finally, key design requirements about gap opening, shear panel, and self-centering capability were discussed.