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Title of the thesis: Experimental investigation and probabilistic modeling of the mechanical properties of finger joints and glued laminated timber beams

Thesis defender: Farid Vafadar Estiar
Opponent: Prof. Josef Füssl, TU Wien, Austria
Custos: Prof. Gerhard Fink, Aalto University School of Engineering/ TU Munich, Germany

The construction sector has a significant environmental footprint, with substantial greenhouse gas emissions, and reducing these impacts is essential for sustainable development. Using engineered wood products as structural materials in the construction industry offers a solution because these products are made from renewable, naturally grown material (i.e., wood), and their use in construction can help store carbon and reduce the environmental footprint. 

Among these products, glued laminated timber (GLT) beams are widely used in construction owing to their strength, light weight, and versatility across a range of structural applications. GLT beams are constructed from timber boards connected end-to-end using finger joints (FJs). The mechanical performance (i.e., strength and stiffness) of these beams depends on both the properties of the timber boards and the quality of the FJs. Because timber is a natural material with inherently variable mechanical properties, the strength and stiffness of GLT beams can vary significantly, making the prediction of their behavior in structures challenging and reducing their competitiveness in the construction industry. Improving these predictions helps optimize material use and promotes timber construction. 

This doctoral research tackles this challenge through extensive experimental testing of FJs and full-scale GLT beams, combined with probability-based modeling. The main result of the study is a contribution to the understanding, development, and validation of models for predicting the mechanical properties of FJs and GLT beams.

The results are applicable to quality control, production design, probabilistic modeling, numerical simulation, and optimization of GLT beams. Overall, this work supports the broader adoption of GLT beams in construction, thereby reducing the building industry's environmental impact and promoting sustainable development.

Keywords: Glued laminated timber beam, Finger joints, Experimental investigation, Probabilistic modeling

Thesis available for public display 7 days prior to the defence at . 

Contact information: farid.vafadarestiar@aalto.fi