Lateral performance of post-tensioned cross-laminated timber shear walls

For the post-tensioned cross-laminated timber (CLT) shear walls under the lateral loads, their lateral bearing capacities may decline significantly, once the concentrated damages occur within the metal connection area. To avoid such a damage mode, it is proposed that the post-tensioning steel strands should be incorporated into the CLT shear wall panels, forming the post-tensioned (PT) CLT shear wall. The CLT shear wall panels are post-tensioned to the foundation by the PT strands. Three PT-only CTL shear walls with different initial post-tensioning stress and one energy-dissipating PT CLT shear wall were tested under the quasi-static reversed cyclic loads. Each scaled shear wall specimen is composed of the upper CLT wall panel, the lower CLT wall panel, and the middle structurally designed CLT-steel hybrid floor diaphragm system. For both the PT-only CTL shear walls and the energy-dissipating PT CLT shear wall, the mechanical properties, the deformation mode, variation characteristics of the post-tensioning force, and the damage modes were analyzed, based on the experimental results. The maximum static-friction coefficient between the CLT and the foundation was also calculated. Furthermore, the improved energy-dissipating ability provided by the adopted dissipaters was also studied. It is found that the PT CLT shear walls can provide ideal lateral load-resisting performance. Besides, almost no damages were observed on the shear wall specimens after the tests. The structurally designed CLT floor diaphragm can reduce the deformation of the CLT floor panels under the perpendicular-to-the-grain compressive stress, while transferring the force from the upper wall panel to the lower wall panel efficiently. It is confirmed that the adopted dissipaters can improve the energy-dissipating ability of the shear walls to a certain extent; whereas, the dissipater-to-CLT connecting method can be further improved in the future to give full play to the energy-dissipating performance of the dissipaters. © 2020, Editorial Office of China Civil Engineering Journal. All right reserved.