Hybrid Mass Timber Building Proves Resilient in Full-Scale Shake-Table Test

A six-story mass timber–steel hybrid building performed well under full-scale seismic testing at the Natural Hazards Engineering Research Infrastructure (NHERI) outdoor shake-table facility at the University of California, San Diego, according to findings published on Wednesday in the Journal of Structural Engineering.

The research team—Tanner Field and Andre R. Barbosa of Oregon State University with Steve Pryor, Barbara Simpson, Patricio Uarac, Arijit Sinha, and John W. van de Lindt—evaluated the building’s dynamic behavior and resilience. The structure combined a mass timber self-centering rocking wall (SCRW) in one direction with a steel moment and concentrically braced frame (MF/CBF) in the other.

The SCRW used a mass timber panel, bounding columns, U-shaped flexural plates for energy dissipation, and post-tensioned threaded rods for recentering. The MF/CBF incorporated wide-flange steel shapes with replaceable fuse elements. The gravity system used mass timber diaphragms, beams, and columns with steel connections designed to reach 5% rotations with minimal damage.

Shake-table motions represented four ground-shaking intensities—43-year, 225-year, design earthquake, and risk-targeted maximum considered earthquake. The SCRW and MF/CBF limited residual drifts to under 0.25%, while isolating inelastic deformations to the U-shaped plates and fuse systems. Peak inter-story drifts were 1.65% and 1.04%, respectively.