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Driven by demand for sustainable buildings and reduction in construction time, mass timber, specifically cross-laminated timber (CLT), is being more widely used in mid-rise buildings in the US. In areas of the US with a significant seismic (i.e. earthquake) hazard, mass timber buildings that are seismically resilient are of significant interest. Low damage post-tensioned self-centering CLT shear walls (SC-CLT walls) provide an opportunity to develop seismically resilient CLT buildings. There is however insufficient knowledge of the lateral-load response and damage states of SC-CLT walls under multidirectional seismic loading conditions, which can have a pronounce effect on the seismic resilience of buildings with SC-CLT walls. In order to fill this knowledge gap, a series of lateral-load tests were performed at the NHERI Lehigh Large-Scale Multi-directional Hybrid Simulation Experimental Facility to investigate the multidirectional cyclic behavior of a low damage, resilient three-dimensional CLT building sub-assembly with SC-CLT coupled shear walls, CLT floor diaphragm, collector beams, and gravity load system. Comparisons are made between the lateral-load experimental response of the SC-CLT walls under unidirectional and multidirectional cyclic loading. 

This paper presents an experimental study on the multi-directional cyclic lateral-load response of post-tensioned self-centering (SC) cross-laminated timber (CLT) shear walls. The SC-CLT wall damage states are introduced and qualitatively defined in terms of the level of effort needed to repair the wall to restore its initial functional state. A comparison between SC-CLT wall damage states under unidirectional and multi-directional loading is presented. The experimental test results show that the SC-CLT wall damage state initiation occurs at lower story-drifts under multi-directional loading compared to unidirectional loading. The SC-CLT wall damage states are quantified in terms of the engineering demand parameter (EDP) defined as wall story-drift. Fragility functions that relate the conditional probability of the occurrence of a selected damage state at a wall corner to the EDP are developed. The results reinforce the observations that multi-directional loading on the CLT shear walls causes more damage that unidirectional loading. 

Drywall partition walls (DPW) could considerably affect the seismic resilience of tall cross-laminated timber (CLT) buildings due to cost and building downtime associated with repair. These drift sensitive components are susceptible to damage at low shaking intensities, and thus controlling or eliminating such damage in low to moderate earthquakes is key to seismic resilience. Conversely, post-tensioned CLT rocking walls have been shown to be a resilient lateral load resistant system for tall CLT building in high seismic areas. A series of tests will be performed at the NHERI Lehigh EF to compare the performance of DPWs with conventional slip-track detailing and alternative telescoping slip-track detailing (track-within-a-track deflection assembly), and to evaluate different approaches for minimizing damage at the wall intersections through the use of gaps. Moreover, a configuration is examined with partition wall encapsulating the rocking wall for fire protection. This paper presents a summary of pre-test studies to design the best configuration of DPW to improve the overall resiliency of the structure.