Seismic performance of self-centering steel-timber hybrid shear wall structures

This paper presents the seismic performance assessment of self-centering steel-timber hybrid shear wall (SC-STHSW) structures. The hybrid structure introduces extra re-centering action to itself through the combination of the post-tensioned steel frame (PTSF) with the light-framed wood shear wall. Slip friction dampers (SFDs) are used as connectors between the frame and the wood wall. An OpenSees model for the SC-STHSW was established and validated versus experimental results. Then, a 9-story SC-STHSW structure was designed with the direct displacement-based design procedure, and the design was checked through nonlinear time history analysis. Based on the designed 9-story SC-STHSW structure, the influence of a key parameter (i.e., self-centering ratio αE) on the structure's dynamic performance was investigated by considering different hazard levels. The dynamic response of three 9-story SC-STHSW structures with different αE values was compared in terms of maximum inter-story drift (MaxISD) and maximum residual inter-story drift (MaxRISD). Meanwhile, the fragility curve of a 9-story conventional steel-timber hybrid shear wall (STHSW) structure without self-centering capability was calculated based on the cloud analysis, and the fragility curves were compared with those of the 9-story SC-STHSW. It was found that the increase of αE was not only beneficial to decrease the system's MaxRISD but also positive in enhancing system's control over its MaxISD. The lower limit of αE was suggested to be 0.6 when the system was used in high seismic regions. The 9-story SC-STHSW (αE = 0.6) was comparable to the 9-story STHSW system in regards to the control of MaxISD, which illustrated the advancement of the new system since, at the same time, it had better re-centering ability to decrease post-earthquake repair costs.