The effect of secondary structural elements on the lateral response of multi-story segmented CLT shear walls

The rocking deformation mechanism in Cross Laminated Timber (CLT) shear wall panels highlights the need for a deeper understanding of interactions between wall panels and adjacent/secondary structural components (floors, parapets and lintels). However, there remains a very limited body of research focused on the effects of floor panels and also the detailing of opening areas, which often neglected in practical design, on the lateral response of segmented CLT shear wall systems. This study, therefore, aims to thoroughly investigate the effect of these factors on the lateral response of multi-story multi-panel segmented CLT shear walls by using four different numerical models that differ in the inclusion of secondary elements. For this purpose, various archetypes differing in number of stories, wall panel aspect ratios, and floor panel out-of-plane stiffnesses and configurations are subjected to monotonic pushover analysis to investigate the key characteristics of their lateral response, such as nonlinear deformation capacity, yielding hierarchy, and failure modes. The study highlighted that secondary structural elements and wall panel aspect ratios significantly affect the lateral response of multi-story segmented CLT shear walls. The study also revealed that using wood-frame elements with almost negligible in-plane lateral stiffness for parapets and lintels, instead of CLT, can improve the lateral performance of segmented CLT shear walls. Such walls were able to maintain a force distribution approximately proportional to the relative lateral stiffness of the coupled walls within a story, which led to the almost simultaneous yielding of ductile connections across the coupled walls and prevented the yielding or failure of non-ductile connections.