Wood is one of the most popular renewable natural materials. Nowadays, raw wood is hardly ever used in the construction industry. It has been substituted by glued laminated wood that is processed with the use of high-tech methods, thus eliminating the principal flaws and defects of the natural material. The deformability of glued laminated beams with combined reinforcement has been studied, under which the steel reinforcement of the periodic profile was placed in the dappings of the upper compressed zone, while ribbon-reinforced composite was glued to the bottom of the stretched zone. The graphical charts for the layer change of the deformations of wood, steel, and composite reinforcement from the beginning of the loading application to the moment of destruction are presented.
Timber beams can effectively be reinforced using externally bonded fibre reinforced polymer (FRP) composites. This paper describes a nonlinear 3-dimensional finite element model which was developed in order to accurately simulate the bending behaviour of unreinforced and carbon FRP plate reinforced glulam beams. The model incorporates suitable constitutive relationship for each material and utilises anisotropic plasticity theory for timber in compression. Failure of beams was modelled based on the maximum stress criterion. The results of the finite element analysis showed a good agreement with experimental findings for load-deflection behaviour, stiffness, ultimate load carrying capacity and strain profile distribution of unreinforced and reinforced beams. The proposed model can be used to examine the effect of different geometries or materials on the mechanical performance of reinforced system.
Experimental tests of a composite concrete-cross-laminated timber (CLT) floor system were conducted. The floor system was constructed with 5-ply CLT panels (6.75 in. thick) made composite with a 2.25 in. thick reinforced concrete topping slab. Four series of tests were performed using different specimen configurations and laboratory testing methods. Tests included: (1) Comparative one-way bending tests (CB) to evaluate the performance of alternative shear connectors used to join the concrete slab to the CLT panel; (2) Orthotropic stiffness and strength tests (OS) to evaluate the elastic orthotropic stiffness of the deck system and provide strength results for weak-axis bending and negative moment strength; (3) Full-scale system performance tests (FS) of a continuous floor span to establish strength at realistic span lengths and the influence of continuity; and (4) Long-term deformation tests (LT) to investigate creep deflections of the composite concrete-CLT floor system considering positive and negative bending influences.
Results include overall strength, elastic stiffness values, deformation capacity, slip deformations along the concrete-CLT interface, predicted neutral axis locations in the composite concrete-CLT systems, and connection deformations.