Shake-Table Testing of a Full-Scale Six-Story Resilient Mass Timber–Steel Hybrid Building

Seismically resilient buildings can resist seismic demands while maintaining a minimum acceptable level of functioning. A six-story mass timber-steel hybrid building was built and tested on the Natural Hazards Engineering Research Infrastructure at University of California, San Diego (NHERI@UCSD) outdoor shake-table facility to study the dynamic behavior of a mass timber self-centering rocking wall (SCRW) and a resilient steel moment frame and concentrically braced frame (MF/CBF) in the east-west and north-south direction, respectively. The SCRW consisted of a mass timber panel, bounding columns, U-shaped flexural plates (UFPs) for energy dissipation, and post-tensioned threaded rods providing recentering. The MF/CBF consisted of typical steel wide flange shapes enhanced by replaceable fuse technology for energy dissipation. The gravity system utilized various mass timber products for the diaphragms, beams, and columns, with steel gravity connections explicitly designed to reach 5% rotations with minimal damage. The building was subjected to shake-table motions scaled to four ground shaking intensities: 43-year return period, 225-year return period, design earthquake, and risk-targeted maximum considered earthquake. The design of the building, test methods, and results are described in this paper. The SCRW and MF/CBF limited residual drifts to less than 0.25% while isolating inelastic deformations to the UFPs and fuse system, respectively. Additionally, measured peak inter-story drift ratios throughout testing were 1.65% and 1.04% for the SCRW and MF/CBF, respectively.