Design and Cyclic Experiments of a Mass Timber Frame with a Timber Buckling Restrained Brace

Abstract

Mass timber buildings are increasing in popularity as the building industry aims to use more sustainable construction materials. A lateral force resisting system with a mass timber frame and a timber buckling restrained brace (TBRB) is presented as a possible solution to allow the expanded use of mass timber in buildings located in cities with high risk of natural hazards such as earthquakes and hurricanes. A series of nine quasi-static cyclic tests was completed to study the performance of the TBRB frame as well as the elastic performance of the bare mass timber frame. The variables studied included the level of axial force applied to the columns to simulate gravity load and the out-of-plane displacement of the TBRB frame. The mass timber frame was tested four times with a different TBRB. The four subassemblies achieved a drift ratio of at least 2.8% before failure of the TBRB due to weak axis buckling of the steel core. The maximum displacement ductility of the four TBRB frame subassemblies ranged from 3.1 to 3.5. The addition of the TBRB enhanced the energy dissipation capacity of the bare mass timber frame by 4.0 to 8.6 times after 14 cycles of lateral displacement.