Development and experimental verification of a pre-pressed spring self-centering energy dissipation brace

The present study develops and experimentally verifies a new type of earthquake-resilient bracing system. The proposed pre-pressed spring self-centering energy dissipation (PS-SCED) bracing system combines friction energy dissipation devices between inner and outer tube members with a mechanism of pre-pressed disc springs that provides a self-centering capability and additional energy dissipation. Two large-scale PS-SCED braces with different types of inner tube members are designed, fabricated, and tested under low cyclic reversed loadings, and the results demonstrate that the PS-SCED braces exhibit stable and repeatable flag-shaped hysteretic responses with excellent self-centering capabilities, effective energy dissipation, large ultimate bearing capacity, and appreciable ductility. The residual deformation of the brace is controlled by adjusting the ratio of the initial pre-pressed force of the disc springs to the friction force provided by the energy dissipation devices. The energy dissipation and ductility of the PS-SCED brace constructed with a circular inner tube are better than those of the brace constructed with an X-shaped inner tube. A restoring force model for the PS-SCED brace is proposed, and the predicted hysteretic responses agree well with the experimental results.