Hybrid Self-Centering Connection Employing Energy Dissipation Sequences: Experimental Study and a Structural Seismic Demand Perspective

This study reported an experimental study of hybrid-self-centering connections (HSCCs) employing energy dissipation sequences. The dual self-centering mechanism of the connection consisting of post-tensioned (PT) steel strands and shape memory alloy (SMA) bolts provided the self-centering driving force, and the energy dissipation sequences can be realized by friction dampers and SMA bolts. An experimental program employing five proof-of-concept connections was tested under the cyclic loading scenarios. The test results including hysteretic responses, strain gauge readings, force evolution in PT steel strands, strength and stiffness, energy dissipation capability, and self-centering ability were examined and discussed. The obvious trilinear hysteretic feature of the test connection accompanied by excellent self-centering ability, moderate energy dissipation capability, and satisfactory ductility was confirmed. In addition, the encouraging repairability of the test connection was verified by retests of repaired specimens. Subsequently, finite element (FE) models verified by the experimental results were developed to further examine the behavior of the proposed connection. A design model was developed enabling the quantification of the multilinear behavior of moment-rotation responses of the proposed connection. The good agreement between the stiffness and strength of the connection from the test data confirmed the rationality of the proposed design model. The analysis results of nonlinear spectral analyses confirmed the effectiveness of structures equipped with the HSCC in reducing acceleration response.