Thesis Defence: The Effect of Structural Interactions Due to Floors, Parapets and Lintels on The Lateral Response of Segmented Cross Laminated Timber (CLT) Shear Walls

Seyed Saeed Askariani, supervised by Dr. Lisa Tobber, will defend their thesis titled “The Effect of Structural Interactions Due to Floors, Parapets and Lintels on The Lateral Response of Segmented Cross Laminated Timber (CLT) Shear Walls” in partial fulfillment of the requirements for the degree of Master of Applied Science in Civil Engineering.

An abstract for Seyed Saeed Askariani’s thesis is included below.

Defences are open to all members of the campus community as well as the general public. Registration is not required for in-person defences. Please email lisa.tobber@ubc.ca to receive the Zoom link for this defence.

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ABSTRACT

Cross-Laminated Timber (CLT) buildings are innovative timber structures constructed exclusively from CLT panels, which serve as both walls and floors, with CLT walls acting as both gravity and lateral load resisting systems. There are two main construction techniques for CLT buildings: platform-type and balloon-type methods. Platform-type construction involves building each floor on top of the walls below, while balloon-type construction features continuous walls that extend from the foundation to the roof with floors attached at each story level.

In platform-type construction method, CLT shear walls can be built using either single monolithic panels or multiple segmented panels. Under seismic lateral loads, segmented CLT shear walls demonstrate more flexible behavior, effectively dissipating energy through their vertical inter-panel connections, largely due to rocking deformations. In contrast, monolithic CLT shear walls primarily dissipate energy through shear deformations at their wall base connections, where sliding deformations dominate their response. The rocking deformation mechanism in segmented wall panels highlights the need for a deeper understanding of interactions between wall segments and adjacent structural components. However, there remains a very limited body of research focused on the effects of floor panels and the detailing of opening areas, which are 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 one- and multi-story segmented CLT shear walls by using four different numerical models that differ in the inclusion of floors, parapets and lintels. The nonlinear behavior of connections is calibrated against existing test data to validate the accuracy of the finite element (FE) models in reproducing the hysteretic behavior of previously tested segmented CLT shear walls. For the purpose of this study, various archetypes differing in height, geometries, wall panel aspect ratios, floor panel bending stiffnesses, and withdrawal stiffnesses of wall-to-floor connections 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 results showed that the inclusion of floors, lintels, and parapets, along with variations in wall panel aspect ratios and wall-to-floor connections, significantly influenced the lateral response of segmented CLT shear wall systems.