You are encouraged to attend the defence. The details of the defence and attendance information is included below:

Date:  November 26, 2024
Time: 10:00 AM to 12:00 PM (PT)

Defence mode: Hybrid
In-Person Attendance: Wood Innovation and Design Centre (WIDC) – Classroom Rm 240 
Virtual Attendance: via Zoom

LINK TO JOIN:  Please contact the Office of Graduate Administration for information regarding remote attendance for online defences.

To ensure the defence proceeds with no interruptions, please mute your audio and video on entry and do not inadvertently share your screen. The meeting will be locked to entry 5 minutes after it begins: please ensure you are on time.

Thesis entitled:  OPTIMIZING HOLLOW FLOOR SYSTEMS WITH STRUCTURAL COMPOSITE LUMBER THROUGH SCREW-GLUING METHOD AND PARAMETRIC MODELLING

Abstract: Mass timber construction has gained significant attention for its sustainability and off-site construction, but conventional mass timber products like cross-laminated timber (CLT) often face challenges in long-span applications due to material inefficiency. Structural composite lumber (SCL), including mass ply panels (MPP), laminated veneer lumber (LVL), and laminated strand lumber (LSL), offers a more efficient solution with superior material utilization, dimensional stability, and strength. This research focuses on developing an optimized, prefabricated hollow floor system using SCL, integrated with the screw-gluing method and optimization algorithm to improve both performance and material efficiency.

Experimental tests demonstrate that the screw-gluing method is a feasible alternative to traditional hydraulic gluing techniques. Key findings indicate that screw spacing, rib width, and flange thickness significantly affect the performance of screw-glued connections, while screw length has a minimal impact. Reducing screw spacing to 150 mm improved load-bearing capacity, and rib widths above 75 mm resulted in diminishing performance gains. Flange thickness also had a critical influence, with increased thickness negatively impacting connection stiffness and load capacity in certain configurations. These findings provide essential insights into optimizing screw-glued timber connections.

In addition, a parametric optimization algorithm was developed by integrating parametric geometry modeling, material databases, design verification methods, including the stressed skin design method in CSA O86, Gamma method, and the shear analogy method. Genetic algorithm was also used to automatically iterate through input parameters, overcoming the drawbacks of traditional, manually iterative, and time-consuming structural design process. The study also compared different methods for calculating the effective width of hollow floor modules, with CSA O86 and Kikuchi methods yielding similar results, while Eurocode 5 provided more conservative estimates. The optimization results demonstrated that hollow floor systems could achieve up to 75% material savings compared to CLT and 67% compared to solid MPP panels, while also reducing floor height by approximately 30% relative to I-joist systems under deflection-controlled conditions. Furthermore, vibration-controlled criteria were considered as an additional optimization objective, achieving up to 60% and 50% material savings compared to CLT and MPP solid panels, respectively.

Examining Committee: 
Chair: Dr. Matt Reid, University of Northern British Columbia 
Supervisor: Dr. Jianhui Zhou, University of Northern British Columbia 
Co-Supervisor: Dr. Maik Gehloff, University of Northern British Columbia 
Committee Member: Dr. Thomas Tannert, University of Northern British Columbia 
External Examiner: Dr. Lei Zhang, University of Alberta