You are encouraged to attend the defence. The details of the defense and attendance information is included below:
Date: 10 December 2025
Time: 1:00 PM (PT)
Defense mode: Remote
Virtual Attendance: via Microsoft Teams
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Dissertation entitled: SEISMIC RESPONSE OF TIMBER BUILDING FRAME WITH INFILL PANELS
Abstract: In the design of mass timber buildings, the focus has traditionally been on primary lateral load-resisting systems (LLRS), such as moment-resisting frames (MRFs) and shear walls. Meanwhile, infilled timber walls are generally treated as non-structural components, and their contribution to lateral resistance is not considered. This practice stems from limited experimental data and oversimplified modeling approaches, systematically excluding these secondary elements from lateral resistance calculations. Consequently, designers often overlook the demonstrated potential of infill walls to substantially enhance seismic performance and structural resilience.
This thesis addresses this gap by demonstrating that integrating timber walls can fundamentally transform the seismic response of mass timber structures. Specifically, it investigates Cross-Laminated Timber (CLT) and Light Timber Frame (LTF) wall panels as integral components of the global system, emphasizing their contributions to strength, stiffness, and energy dissipation.
A detailed numerical modeling framework was developed in OpenSees to capture the nonlinear behavior and connection hysteresis governing wall to frame interaction. The research employs a component and system level modeling approach: first calibrating individual connector models for wall systems against experimental results, and then extending them to simulate multi-story, multi-bay timber frames. The models explicitly capture strength and stiffness degradation, pinching, and cyclic energy dissipation in wall to frame connections. Both pushover and nonlinear time history analyses were performed to assess the structural response under design-level seismic loading.
The results clearly demonstrate that the addition of infill walls significantly alters the overall structural behavior. Compared to the bare frame, the infilled systems exhibited a 50 to 90% reduction in fundamental period, an 80 to 90% decrease in inter-story drift, and a substantial increase in lateral load capacity by 3 to 10 times for LTF walls and 15 to 47 times for CLT walls, respectively. While CLT walls contributed greater stiffness and strength, LTF walls provided higher ductility and energy dissipation. Overall, these results demonstrate that the inclusion of infill walls shift mass timber buildings from frame-controlled to wallcontrolled behavior, greatly enhancing their seismic resilience.
The research establishes timber infill walls as effective components of the lateral load resisting system, with connection detailing emerging as a key governing factor. Wall–frame connections are integral components of the system whose nonlinear behavior cannot be accurately captured through simplified numerical modeling approaches, emphasizing the necessity of detailed modeling for realistic response prediction. Wall–frame connections enable robust composite action, transforming infill walls into active seismic components. The developed and validated models provide a foundation for performance-based seismic design of mass timber structures, where CLT walls optimize for strength and stiffness, and LTF walls excel in ductility and energy dissipation.
Defence Committee:
Chair: Dr. Roger Wheate, University of Northern British Columbia
Supervisor: Dr. Asif Iqbal, University of Northern British Columbia
Committee Member: Dr. Shahria Alam, University of British Columbia
Committee Member: Dr. AHM Muntasir Billah, University of Calgary
Committee Member: Dr. Ahmed Hamada, University of Western Ontario
External Examiner: Dr. Thang N. Dao, The University of Alabama
