Stress-laminated timber (SLT) decks in bridges are popular structural systems in bridge engineering. SLT decks are made from parallel timber beams placed side by side and pre-stressed together by means of steel rods. SLT decks can be in any length by just using displaced butt joints. The paper presents results from friction experiments performed in both grain and transverse direction with different levels of pre-stress. Numerical simulations of these experiments in addition to comparisons to full-scale experiments of SLT decks presented in literature verified the numerical model approach. Furthermore, several alternative SLT deck configurations with different amounts of butt joints and pre-stressing rod locations were modelled to study their influence on the structural properties of SLT decks. Finally, some recommendations on design of SLT bridge decks are given.
The proposed paper presents two alternative strategies for using fast-growing, low-grade softwood for modern engineered wood products. A chemical based strategy is explored first with the testing of polymer-impregnated small clear wood samples. A second mechanical based strategy based on the tectonics of stress-laminated bridge decks is examined in further detail with 1:10 scaled structural models, followed later on by full-scale testing. The relative benefits and disadvantages of each strategy are compared to each other, and benchmarked against regular sawn timber and conventional engineered wood products like glulam and cross-laminated timber.