The need to include economical and yet environmentally friendly products in modern day structural systems has pushed the development of engineered wood products such as engineering wooden I-joists. These products are engineered to resist high transverse loads and use the wood material more efficiently. Beam members, especially those that are deep and have long spans, are prone to lateral-torsional buckling as a possible mode of failure. Laboratory testing rarely take into account actual end conditions and initial imperfection which might have a significant impact on the buckling behavior of beams. The current research project aims to investigate the lateraltorsional buckling of wooden I-joists. A total of 41 joists were tested using various commercial joists hangers and enhanced connections to represent different support conditions. A numerical 3D model was also developed using commercially available finite element program ABAQUS to determine the buckling loads and associated mode shapes of joists similar to those tested. It was demonstrated that the lateral stiffness of the joists' top flange support has a significant influence on the buckling load and that a stiffness variation of the bottom flange lateral support shows no significant impact on the buckling load. The results also suggest that an enhanced rotational connection can significantly increase the buckling load of a member. The verified FE model was capable of predicting the buckling load of wood I-joists with various end conditions and initial imperfections with reasonable accuracy.
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AcknowledgementsI would like to express my deepest gratitude to my supervisor, Dr. Ghasan Doudak, to have given me the opportunity to work on this project. With his time and guidance, I have been able to accomplished this challenge and expand my engineering expertise. A special thanks goes to Dr. Magdi Mohareb for his support, his time in the examination of my work and the advice he has given me throughout the years. I must express my deepest gratitude to Simpson Strong-Tie to have provide the joists hangers tested with these experiments and Boise Cascasde for the I-joists specimens. I would also like to thank my student colleagues, Mr. Daniel Lacroix for the guidance and help, and Mr. Rémi St-Amour for helping me conduct the experimental work. I would like to also thank Ms. Ghazanfarah Hafeez, Ms. Sarah De Carufel, Mr. Corey Guertin Normoyle and Mr. Christian Viau for making these university years a great experience. J'aimerais remercier tout spécialement ma partenaire Clotilde Maurice, qui a toujours cru en mes capacités, qui m'a écouté et guidé dans mon cheminement et qui m'a fourni un soutien financier lors des dernières années. Sans elle à mes côtés, je n'aurais jamais pu entreprendre et relevé un tel défi professionnel. Je remercie également mes parents qui m'ont supportés dans nos décisions et m'ont permis de poursuivre ce rêve académique. Un merci tout particulier à mon ami de longue date, Bruno St-Aubin, avec qui j'ai passé plusieurs soirées à échanger des idé...