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Due to its average mechanical properties, poplar, a fast-growing species, has been disfavored compared to stronger species for several decades. Wood-based products may help changing that perspective and thus, poplar has been gaining its market share for structural uses. A state-of-the-art review concerning the use of poplar to produce glued laminated products, with special focus on the use of Portuguese poplar, is presented. The Portuguese forest produces a great variety of species. The most common poplar species found in this country are Populus x canadensis, P. nigra L., and P. alba L. Despite its limited availability, and the market hesitation on its structural application, recent studies on poplar grown in the Portuguese forest showed its suitability for structural purposes. Glued laminated timber (GLT) beams made with this species revealed a very promising mechanical behavior. Bending strength tests evidenced a ductile behavior on more than 70% of the beams, which motivated deepening the study on the raw material used to produce those beams. To predict the mechanical behavior of such beams, a 3D numerical model was developed. The numerically predicted results were compared with the experimental ones, showing very good agreement between both approaches.

Poplar wood is a light, soft, and fast-growing timber from a hardwood species, characteristics that make it suitable for several applications. This study focused on the mechanical characterization of Portuguese poplar species, namely white poplar (Populus alba) and black poplar (P. nigra), aiming for its structural use. Therefore, a sample of lamellae was assessed to determine its density and dynamic modulus of elasticity, using a non-destructive device, based on longitudinal vibrations. Clear wood specimens were obtained from a set of lamellae to perform tension and compression parallel-to-grain tests. These tests were used to determine the moduli of elasticity in tension and compression and the tensile and compressive strengths and strains. Also, typical stress-strain curves were identified for the sample studied. The results stressed the potential for structural applications of Portuguese poplar.

The gluing process of thin wood veneers is a crucial step for the use of wood as a finishing layer to injected plastic parts, through the overmolding process. Based on the published studies on pine wood gluing for the production of laminated veneer lumber (LVL) and plywood panels, a phenol–resorcinol–formaldehyde (PRF) glue was selected for the assessment of the gluing process of Portuguese maritime pine wood. The gluing of the wood veneers was carried out in a hot pressing machine, equipped with electronic temperature control, under 800 kPa of applied pressure, and a glue mix spread rate of 350 g/m2. The influence of the gluing parameters (gluing temperature and pressing time) on dimensional and physical properties of the glued wood veneers was evaluated. Additionally, experimental determination of bending strength and modulus of elasticity of the glued wood veneers were carried out through three-point bending tests. According to the results obtained, and despite the uncertainties that need to be addressed, it seems feasible to consistently glue maritime pine wood veneers to use them as a top layer in the overmolding process of plastics.

Timber-concrete composite (TCC) solutions are not a novelty. They were scientifically referred to at the beginning of the 20th century and they have proven their value in recent decades. Regarding a TCC floor at the design stage, there are some assumptions, at the standard level, concerning the action of concentrated loads which may be far from reality, specifically those associating the entire load to the beam over which it is applied. This naturally oversizes the beam and affects how the load is distributed transversally, affecting the TCC solution economically and mechanically. Efforts have been made to clarify how concentrated loads are distributed, in the transverse direction, on TCC floors. Real-scale floor specimens were produced and tested subjected to concentrated (point and line) loads. Moreover, a Finite Element (FE)-based model was developed and validated and the results were collected. These results show that the “loaded beam” can receive less than 50% of the concentrated point load (when concerning the inner beams of a medium-span floor, 4.00 m). Aiming at reproducing these findings on the design of these floors, a simplified equation to predict the percentage of load received by each beam as a function of the floor span, the transversal position of the beam, and the thickness of the concrete layer was suggested.

Timber-concrete composite floors can be seen as bi-dimensional elements constituted by repeatable longitudinal elements (timber beams) connected through an element capable to spread the load on the transverse direction (concrete slab). This is usually a fact to “take advantage of” in terms of design, in the light of current regulations, with the analysis of a “T-shape” beam. Nevertheless, when concerning the action of concentrated loads, considering them supported entirely by the beam to which they are applied can result in a disadvantage rather than an advantage. This study focus on the distribution of load in the transverse direction when composite floors are subjected to concentrated loads. There were analyzed not only timber-concrete composite floors, that already have proven their value, but also relatively new solutions as those using cross laminated timber (CLT) combined with steel beams. The results show that the load received by “the loaded beam” can be far from 100%.

Some aspects of the structural behaviour timber–concrete floors are still not fully known. This is the case of transverse load distribution for point and line loads. This article presents a study on timber–concrete floors subjected to point and line loads. A set of composite floors, each comprising five beams, was tested in order to evaluate how some parameters might affect the load distribution. These results were compared to those obtained with a numerical model developed by the authors. Typically, the beam underneath the load takes the highest percentage of the applied load and the distribution for the remaining beams is significantly affected by the span. For composite slabs with medium spans (L = 4.00 m), when the load is applied at the central beam midspan only 37% of the load is received by this beam, with 69% of the load being carried by the composite T-beams adjacent to the middle one and the remaining share (about −6%) resulting from the relieving in the load received by the outer beams.

The behavior of timber–concrete slab-type structures is not fully understood yet. This is the case of the transversal load distribution in composite floors under concentrated loads. Included in a broader investigation, this article presents the findings for the specific case of a timber–concrete composite floor under the action of a concentrated load. This article aims at studying such transversal load distribution by means of some theoretical methods, which were compared with experimental results. Different finite elements (FE) and analytical models were used. Numerical models using different types of FE were validated based on numerical and experimental results. The analytical model used distribution coefficients. From the study, it was possible to conclude that all the methods were able to detect a non-linear transversal distribution, but there were some deviations when comparing the methods with each other. The analytical method, based on several simplifications presented a larger deviation from the numerical ones. This is discussed in more detail within this article and some practical considerations were added.

In this paper the transversal load distribution in timber-concrete systems is analysed and discussed. The analysis is based on experimental and numerical results obtained for real scale timber-concrete systems. Two situations are considered: a timber-concrete floor for a multi-storey building with dimensions of 3.39mx3.48m in plan view and a road bridge deck with dimensions of 5mx14m also in plan view. In both situations the systems were designed to the loads required by the European codes. The effect of the transversal load distribution was experimentally assessed by imposing concentrated loads in various locations, eccentric to both transverse and/or longitudinal direction. Additionally, FEM models were developed to describe the mechanical behaviour of the two composite timber-concrete systems. The results obtained with both methodologies are presented and discussed. Based on this discussion conclusions are drawn regarding the amount of transversal distribution that can be expected in this type of reinforcement solution.

The aim of this study is to analyze the mechanical behavior of timber—concrete connections established through glued notches, as well as the parameters that may affect it, specifically in the experimental shear test procedure. With these objectives in mind, a database based on a literature survey was created, identifying different shear test set-ups. In addition, a numerical approach was also adopted, based on experimental results. A numerical finite element method model was developed in order to describe the behavior of this type of connection. To validate the model, three sets of experimental tests were used, differing according to the notch material, the concrete class and the set-up’s geometry. Using this model, parametric studies were developed to analyze the effects of the material and geometrical parameters and support conditions. The database showed that double-shear tests were the most common experimental test set-up. The numerical modeling allowed a good approximation to a connection’s linear-elastic behavior. Parametric studies showed that the parameter with the greatest effect on a connection’s stiffness was the modulus of elasticity of timber, in contrast with the support conditions. The locations chosen to measure displacements on timber and concrete elements were also shown to affect the calculated connection stiffness.