Global analysis in 258 mid- and high-rise mass timber buildings: Structural classifications, core system, architectural design, and emerging practice

A coherent understanding of structural systems and design principles behind tall mass timber buildings is still missing. This study focused on 258 finished mass timber projects worldwide. It examined the definitions of low-, mid- and high-rise timber buildings, structural classifications, core system designs, geographic distribution, link between regional practice and structural choice, functional uses, link among structural typologies, core systems and architectural design trends. A more sophisticated classification framework was proposed for tall mass timber buildings, which identified core material (i.e., timber, concrete or steel) as the main factor governing structural solutions and viewed concrete podiums as essential extensions of the building foundation system from an architectural and urban planning perspective. Core materials play a decisive role in enabling the height of timber buildings. Concrete cores were used in most of those projects to achieve heights above 60 m. Three main structural classifications dominate those 258 mass timber projects: All-Timber (49.2%), Hybrid Timber–Concrete Core (44.2%), and Hybrid Timber–Steel (6.6%). Using timber–concrete core hybrids in high-rise buildings (>25 m) particularly over 60 m, a wider adoption of all-timber systems in mid-rise buildings (≤25 m) and high-rise buildings but below 60 m are the anticipated future development trends.