Experimental and numerical investigations into seismic performance of timber-steel hybrid structure with supplemental dampers

Although building structures can be designed to meet the life safety criterion and to deform inelastically without inducing collapse under major earthquakes, the structural and nonstructural damage associated with inelastic responses is normally very costly to repair. In this paper, friction dampers are utilized to upgrade the seismic performance of timber-steel hybrid structure, which has been proposed as an alternative structural solution for multi-story buildings. The hybrid structural system consists of steel moment resisting frame and infill light wood frame shear wall, both of which serve as the main lateral load resisting components, and friction dampers are introduced as frame-to-wall connectors to mitigate earthquake-induced damage. Pseudo-static loading tests were carried out on three timber-steel hybrid lateral load resisting subassemblies, and test results showed that the friction dampers were very effective in dissipating earthquake input energy, and correspondingly, much less damage was observed within the main structural members. The software package OpenSees was used to simulate the hysteretic behavior of the hybrid structure, and the developed finite element model was further validated by test results. Moreover, an optimal damper design solution was provided for a four-story timber-steel hybrid prototype building according to the numerical results from massive time-history analyses. Finally, the floor acceleration and inter-story drift responses of the prototype building with optimal damper configurations were assessed. This research aims to contribute to the development of novel timber hybrid structural systems with enhanced seismic performance.