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This paper presents an experimental study on the multidirectional cyclic lateral-load response of post-tensioned self-centering (SC) cross-laminated timber (CLT) shear walls. SC-CLT shear wall damage states are introduced and qualitatively defined in terms of the repairs needed to restore the lateral-load response of the SC-CLT wall. A comparison between SC-CLT wall damage states under unidirectional (in-plane) and multidirectional (in-plane and out-of-plane) lateral loading is presented. The experimental results show that the initiation of SC-CLT wall damage occurs at smaller story drifts under multidirectional loading compared to unidirectional loading. Engineering demand parameters (EDPs) are used to quantify the SC-CLT wall damage states. Uncertainty in the EDP value when a damage state occurs is considered and quantified. Using the experimental results, component (i.e., a CLT wall panel corner) and system (i.e., an entire SC-CLT wall) fragility functions are developed and presented. 

Driven by demand for sustainable buildings and a reduction in construction time, mass timber buildings, specifically cross-laminated timber (CLT), is being more widely used in mid-rise buildings in the US. Low damage post-tensioned self-centering (SC) CLT shear walls (SC-CLT walls) provide an opportunity to develop seismically resilient CLT buildings. Previous research focused primarily on the lateral-load response under unidirectional loading of isolated self-centering timber walls, without considering the interaction with the adjacent building structural components, i.e., the floor diaphragms, collector beams, and gravity load system. Buildings response under seismic loading is multidirectional and there are concerns that multidirectional loading may be more damaging to SC-CLT wall panels and the adjacent building structural components than unidirectional loading, which affects the potential seismic resilience of buildings with SC-CLT walls. A series of lateral-load tests of a 0.625-scale timber sub-assembly was conducted at the NHERI Lehigh Large-Scale Multi-Directional Hybrid Simulation Experimental Facility to investigate the the lateral-load response and damage of SC-CLT walls and the capability of the adjacent building structural components i.e., the floor diaphragms, collector beams, and gravity load system to accommodate the building response and the controlled-rocking of the SC-CLT walls under multidirectional lateral loading. 

Two partition walls with return walls at both ends and traditional slip-track detailing were investigated. Special gap details were evaluated to reduce damage at the wall intersection. The first detail utilized a large gap in the wall intersection, while the other detail utilized distributed gaps along the wall. The walls were tested under a bidirectional loading protocol, to provide better insight into the wall intersection behavior under bidirectional loading. 

The slip behavior of two straight drywall partition walls (without return walls) – one with conventional slip-track detailing and the other with telescoping detailing – was examined. These drywall partition walls were tested under a bidirectional loading protocol, which allowed for systematic evaluation of the effect of out of plane drift on the in-plane resistance of the drywall partition walls.