Design， test and parameter identification of self-centering rebar splices

Post-tensioned prestress， self-centering brace and shape memory alloy （SMA） are the main ways to realize the self-centering of the structures. However， the construction of post-tensioned prestress is complex， the concentrated force generated by self-centering brace may cause joint damage， and the SMA is expensive. The disc springs are preloaded to provide the self-centering force. A self-centering rebar splice is developed to connect the longitudinal rebars in the reinforced concrete structures. The calculation method of the stiffness， preload and effective stroke of the self-centering rebar splice is established. Four rebar splices with different preload force， stiffness and effective stroke are designed and manufactured， and the mechanical properties of the rebar splices are tested. The parameters of the rebar splice adopting the Bouc-Wen model are identified based on particle swarm optimization algorithm. The results show that the self-centering rebar splice has a stable half-flag hysteretic curve and excellent self-centering performance. The Bouc-Wen model can accurately describe the hysteretic characteristics of the rebar splice， and the fitting data are in good agreement with the test data.