IMPROVING THE BENDING STIFFNESS OF DLT BEAMS: EXPERIMENTAL ANALYSIS AND ANALYTICAL MODEL VERIFICATION

The search for environmentally friendly building materials has led to the development of dowel laminated timber (DLT), a product in which sawn timber boards are laminated using hardwood dowels. The dowels in DLT reduce the need for metal fasteners and synthetic adhesives. However, the application of DLT beams is challenged by the relatively low bending stiffness resulting from the low composite action. In this research, we evaluated the effectiveness of the dowel composite connection depending on different dowel angle positions to improve the bending stiffness and further enhance the environmental benefits of DLT beams. Double shear tests were performed on three-layer connections assembled with beech wood dowels. Three-layer beams were then fabricated and tested under four-point bending load. The efficiency of the composite action and the resulting flexural behaviour were evaluated. The results show that the angular position of the dowels can improve the bending stiffness by up to 50 %. The simplified design method, also known as the γ-method, was used to estimate the efficiency of composite beams. A comparison of the experimental and theoretical results helps to verify the feasibility of the EC5 model for composite beams for use with DLT beams.