Experimental Investigation of Self-Centering Cross-Laminated Timber Walls

Abstract

Mass timber is an attractive and sustainable alternative structural engineering material to concrete and steel. Despite successful midrise to high-rise timber building projects around the world, such buildings have not been implemented in regions with high seismicity due in part to a lack of research and development on appropriate ductile seismic load resisting systems for heavy timber construction. This paper describes experiments conducted to develop a resilient lateral force-resisting wall system that combines cross-laminated timber (CLT) panels with vertical posttensioning (PT) to provide postevent recentering. Supplemental mild steel U-shaped flexural plate (UFPs) are intended to yield under cyclic loading while the PT and CLT components remain undamaged until large interstory drifts are experienced by the wall. The experiments were designed to explore various limit states for self-centering CLT (SC-CLT) walls, including their dependence on design variables and their effect on performance, and to investigate strength and stiffness degradation at large interstory drifts. It was found that the SC-CLT walls were able to recenter even after large drift cycles and the crushing of the CLT material was the governing limit state for most specimens. A hierarchy of desirable limit states was identified consisting of UFP yielding, CLT splitting, PT yielding, and CLT crushing.