Academic literature on the topic 'Steel-timber composite beams'

Abstract This paper presents an analysis of timber-concrete composite beams. Said composite beams consist of rectangular timber beams and concrete slabs poured into the steel sheeting. The concrete slab is connected with the timber beam using special shear connectors. The authors of this article are trying to patent these connectors. The article contains results from a numerical analysis. It is demonstrated that the type of steel sheeting used as a lost formwork has an influence on the load-bearing capacity and stiffness of the timber-concrete composite beams.

The lateral torsional buckling (LTB) of steel-timber composite (STC) beam with partial interaction was investigated in this paper. The composite beam is constructed by connecting the timber to both flanges of the H-shaped steel with bolts or screws. Twelve push-out specimens were designed to evaluate the shear performance of bolt or screw connectors. It was shown that the slip stiffness and the shear bearing capacity of the connectors increased with the thickness of timber increasing. Then, eight full-scale composite beams with lengths of 6000 mm were studied through bending tests and compared to a bare steel beam. The experimental behaviors of the specimens were identified, including the failure mode, load-deflection relationship and load-strain response. The LTB phenomenon and composite action were discussed by analyzing the strain distribution, stiffness and strength. The results demonstrated that the STC beams fastened with bolts or screws displayed partial composite action. Although the stiffness of the composite beam showed little augmentation, the maximum strength of the composite beam substantially increased by suppressing the LTB phenomenon. A finite element analysis was conducted to reveal the failure mechanism of the specimens with different geometric and physical parameters, including the number of timber layers, the interface shear stiffness and the initial imperfection. It was found that increasing the number of timber layers in the upper flange suppressed the lateral torsional buckling, and the interface shear stiffness was the key factor to control the stiffness and failure modes of STC beams.

To promote the development of timber–steel composite (TSC) structures, this paper proposes a TSC I-beam with an I-beam as the webs, covered with a timber board on its upper and lower surfaces and bolted together; the effect of varying the ratio of the timber board thickness to I-beam on the bending performance of the TSC I-beam was investigated. Considering the same total height of the beam cross-section and the variation of timber board thickness and I-beam height, three groups of six TSC beam specimens were designed and fabricated to carry out bending load failure tests, and the effects of the variation of timber board thickness with respect to I-beam height on the failure mode, flexural load capacity, ductility, and composite degree of TSC beams were analyzed. In addition, a model for predicting the elastic ultimate bending capacity and mid-span deflection of TSC I-beams was proposed on the basis of the composite coefficient method, which avoids the need to test the joints, and the theoretical calculation results were in good agreement with the test results, which can provide a reference for the design of TSC I-beams.

A timber–lightweight−concrete (TLC) composite beam connected with a ductile connector in which the ductile connector is made of a stainless−steel bolt anchored with nuts at both ends was proposed. The push−out results and bending performance of the TLC composite specimens were investigated by experimental testing. The push−out results of the shear specimens show that shear–slip curves exhibit good ductility and that their failure can be attributed to bolt buckling accompanied by lightweight concrete cracking. Through the bending tests of ten TLC composite beams and two contrast (pure timber) beams, the effects of different bolt diameters on the strengthening effect of the TLC composite beams were studied. The results show that the TLC composite beams and contrast timber beams break on the timber fiber at the lowest edge of the TLC composite beam, and the failure mode is attributed to bending failure, whereas the bolt connectors and lightweight concrete have no obvious breakage; moreover, the ductile bolt connectors show a good connection performance until the TLC composite beams fail. The ultimate bearing capacities of the TLC composite beams increase 2.03–3.5 times compared to those of the contrast beams, while the mid-span maximum deformation decrease nearly doubled.

Wooden multi-span beams with steel reinforcement were studied experimentally on a stationary stand using an eight-point loading scheme that simulated a load uniformly distributed over the beam span. The studies were carried out on beams with a span of 4.8 m with a cross-sectional area of 40 mm × 80 mm, reinforced in the stretched zones of the cross-section with rods made of hot-rolled steel reinforcement of A400 class. The rational zones for the location of reinforcements in the tensioned and compressed zones of the beams were determined. The rational placements of reinforcement in the support and span zones was based on the numerical simulation of the volumetric stress state calculated using the finite element method. It was experimentally confirmed that the failure of wood composite beams had a plastic nature and occurred only along normal sections. This excluded the possibility of brittle fracture from shear stresses and ensured the operational reliability of structures as a whole. It was shown that the proposed rational reinforcement of wooden beams increased their bearing capacity by 175% and reduced bearing deformability by 85%. The results obtained indicated high efficiency of the application of the developed method of reinforcement in beams of roofs and floors of buildings.

In this paper, the short-term behaviour of innovative aluminium–timber composite beams was investigated. Laminated veneer lumber panels were attached to aluminium beams with screws. Recently conducted theoretical, experimental, and numerical investigations have focused on aluminium–timber composite beams with almost full shear connections. However, no experiments on aluminium–timber composite beams with partial shear connections have yet been conducted. For this reason, composite action in composite beams with different screw spacing was studied in this paper. Four-point bending tests were performed on aluminium–timber composite beams with different screw spacing to study their structural behaviour (ultimate load, mode of failure, load versus deflection response, load versus slip response, and short-term stiffness). The method used for steel–concrete composite beams with partial shear connection was adopted to estimate the load bearing capacity of the investigated aluminium–timber composite beams. The resistance to sagging bending of the aluminium–timber composite beams with partial shear connections from the theoretical analyses differed by 6–16% from the resistance in the laboratory tests. In addition, four 2D numerical models of the composite beams were developed. One model reflected the behaviour of the composite beam with full shear connection. The remaining models represented the composite beams with partial shear connections and were verified against the laboratory test results. Laminated veneer lumber was modelled as an orthotropic material and its failure was captured using the Hashin damage model. The resistance to sagging bending of the aluminium–timber composite beams with partial shear connections from the numerical analyses were only 3–6% lower than the one from the experiments.

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%.

La mixité acier-bois présente un fort potentiel de développement : les composants en bois et en acier peuvent se renforcer mutuellement ; le bois, par son caractère isolant, peut être utilisé pour protéger l'acier du feu ; l'acier apporte son caractère incombustible. Cette forme de mixité est pourtant peu répandue malgré le récent essor du bois dans la construction de bâtiments multiétagés, à cause du manque de références scientifiques et techniques sur le sujet. On propose alors d'étudier des poutres mixtes pour lesquelles l'acier et le bois sont associés de manière à obtenir des performances les meilleures possibles, en situations normale et d'incendie. On décrit d'abord le comportement des matériaux acier et bois, à froid et en situation d'incendie. Une description de la combustion du bois est proposée pour mieux comprendre ce qui sous-tend l'évolution de ses propriétés avec la température. Un intérêt particulier est porté sur les transferts hydriques qui se produisent dans le bois lorsqu'il brûle. On examine ensuite la question de la mixité acier-bois à travers un aperçu global. Puis on passe en revue les travaux portant sur un certain type de configuration, qui consiste à insérer des poutres en bois entre les semelles d'un profilé en I laminé à chaud, tout en faisant en sorte que ce profilé soit protégé du feu par le bois. La description du comportement élastique à froid des poutres étudiées est réalisée par l'utilisation de la méthode gamma. La réalisation d'essais de flexion sur des poutres mixtes et leurs constituants permet de confirmer ce modèle analytique, mais un effet composite non-anticipé est observé dès lors que l'acier commence à se plastifier. Un gain de résistance significatif est alors permis par l'association du bois et de l'acier. On parvient à simuler ce comportement en augmentant la limite d'élasticité de l'acier modélisé par rapport à la valeur mesurée, ainsi que la résistance du bois en traction longitudinale. Des essais thermiques sur des éprouvettes acier-bois non chargées sont ensuite réalisés. On confirme à cette occasion que la mesure correcte des températures dans le bois nécessite d'orienter les thermocouples parallèlement aux isothermes. De nombreuses configurations sont comparées, ce qui permet d'appréhender finement l'efficacité de la protection au feu des profilés métalliques apportée par le bois. Les transferts de masse qui se produisent dans le bois se révèlent avoir un effet sensible sur la température des profilés métalliques protégés. La comparaison des températures mesurées et simulées permet de mettre en évidence l'importance de l'étanchéité des joints d'assemblage pendant l'exposition au feu. La combustion du bois et la température de l'acier sont observées après la fin de l'exposition au feu, on oppose alors le comportement des configurations creuses à celui des configurations pleines. Finalement, des essais au feu sur des poutres chargées mécaniquement montrent qu'un profilé protégé par une épaisseur de bois de 45 mm peut résister au feu pendant 81 min. On met en évidence un effet du chargement sur la température du profilé métallique par l'intermédiaire d'une ouverture des joints d'assemblage. La simulation numérique montre que le bois contribue à la résistance au feu de la poutre mixte non seulement en protégeant thermiquement l'acier, mais également en reprenant une partie des charges. Ces travaux montrent l'efficacité des poutres mixtes acier-bois, en situation normale et sous incendie, et contribuent à la compréhension de leur comportement. Ils permettent de formuler des propositions d'amélioration et d'identifier de nouvelles problématiques ouvrant des perspectives pour l'étude et l'utilisation de ces poutres mixtes
Timber-steel hybridization has great potential, because steel and timber component can reinforce each other, timber can be used to protect steel from fire, and the non-combustibility of steel can be used in an advantageous way. However, this form of hybridization is not widespread despite recent developments in the use of timber for multi-story buildings. Therefore, it is proposed to study composite beams made from timber and steel combined in such a way that the best possible performances are achieved, in normal and fire situations. Firstly, behavior of steel and timber is described in normal and fire situations. A description of wood combustion is proposed to better understand what underlies the temperature dependence of its properties. A focus is made on the mass transfer that occur into timber as it burns. Then, the timber-steel hybridization is addressed through an overview. Afterward, a literature review is made on a specific configuration type, which is assembled by inserting timber beams between the flanges of a hot-rolled “I” profile, while ensuring that this profile is protected from fire by timber. The description of the elastic behavior of studied beams in normal situation is achieved using the gamma method. Bending tests on hybrid beams and their components corroborate this analytical model, but an unexpected composite behavior is observed when steel yielding begins. Thus, a significant strength gain results from the combination of timber and steel. We manage to simulate this behavior by increasing the yield point of the modeled steel compared to the measured value, as well as the tensile strength of timber. Then, fire tests on unloaded specimens are performed. On this occasion, we confirm that correct temperature measurements into timber require orienting thermocouples parallel to isotherms. Many configurations are compared, which allows to understand in detail the effectiveness of the fire protection provided by wood to steel profiles. Mass transfers that occur into timber appear to have a significant effect on temperatures measured on protected steel profiles. The comparison of measured and simulated temperatures allows to highlight the importance of tightness of assembly joints during exposure to fire. Wood combustion and steel temperatures are observed after the end of the fire exposure, and the behavior of hollow configurations is contrasted with that of the timber filled configurations. Finally, fire tests on mechanically loaded beams show that a steel profile protected using 45 mm thick timber components can resist fire for 81 min. Thus, R60 is exceeded with relatively thin protection. Results show that the loading has an impact on steel temperatures, because of an opening of the assembly joints. Numerical simulations show that timber gives fire resistance of the composite beam both thermally and mechanically, by protecting the steel profile, but also by relieving its load. This work shows the effectiveness of steel-timber composite beams, in normal and fire situations, and contributes to the understanding of their behavior. However, proposals for improvement and new challenges are formulated, opening prospects for the study and use of these composite beams

The aim of this diploma thesis is a design of the multy-storey steel structure with a wooden dome structure of the shopping centre in city of Banská Bystrica, Slovakia. Minimum build-up area is 2 000m2. Minimum number of storeys is set at 2. Steel structure is composed as a frame construction with composite steel-concrete ceilings. Building has 2 storeys at all. Wooden structure of dome is composed by glue laminated curved beams. The structural design and analysis is performed by software SCIA Engineer 15.

The subject of master’s thesis is design and assessment of steel load-bearing construction of atypical family house in Vrchlabí. Structure is designed as multi-storey steel structure, cooperating with stiff concrete core. The design was considered in four different options which combines possibility of using steel, steel and timber with different way of stiffness for whole structure. There is also composite steel-concrete alternative floor trimmer for selected option. Design and assessment was conducted in accordance with the applicable standards and by using software Scia Engineer.

<p>Timber-based composite floors are gaining ascendancy as potential competitors with mainstream steel-concrete composites due to the increasing emphasis on sustainability in the construction industry. This paper investigates the vibration serviceability performance of an innovative prefabricated timber-steel composite floor module. The floor features a cross-laminated timber (CLT) panel joined to cold-formed steel beams using self-tapping screws as shear connectors. The vibration response of the floor module is simulated through the finite element method considering both modal and transient analyses, and its structural performance is evaluated using criteria specified in international design codes and standards. The results provide insight into the vibration behaviour of steel-timber composite floors in residential applications.</p>

<p>Timber-based composite floors are gaining ascendancy as potential competitors with mainstream steel-concrete composites due to the increasing emphasis on sustainability in the construction industry. This paper investigates the vibration serviceability performance of an innovative prefabricated timber-steel composite floor module. The floor features a cross-laminated timber (CLT) panel joined to cold-formed steel beams using self-tapping screws as shear connectors. The vibration response of the floor module is simulated through the finite element method considering both modal and transient analyses, and its structural performance is evaluated using criteria specified in international design codes and standards. The results provide insight into the vibration behaviour of steel-timber composite floors in residential applications.</p>

<p>With a total height of 55m, the Hyperion residential Tower is located near the Saint Jean train Station in Bordeaux France and was designed by the engineering firm Terrell in association with the architectural practice Jean-Paul Viguier &amp; Associates. The structure is braced with a reinforced concrete core, made of cross laminated timber floors, laminated timber beams along the periphery of the building, wood frame walls on the façades, and prefabricated steel balconies placed in situ with cranes. Detailed design of the composite tower was carried out by engineering firm Setec Tpi, through a large use of BIM software’s (Revit and Tekla) from which shop drawings were generated. The main contractor Eiffage had to face many challenges during construction to erect what is now the tallest wooden tower in France.</p>

<p>With a total height of 55m, the Hyperion residential Tower is located near the Saint Jean train Station in Bordeaux France and was designed by the engineering firm Terrell in association with the architectural practice Jean-Paul Viguier &amp; Associates. The structure is braced with a reinforced concrete core, made of cross laminated timber floors, laminated timber beams along the periphery of the building, wood frame walls on the façades, and prefabricated steel balconies placed in situ with cranes. Detailed design of the composite tower was carried out by engineering firm Setec Tpi, through a large use of BIM software’s (Revit and Tekla) from which shop drawings were generated. The main contractor Eiffage had to face many challenges during construction to erect what is now the tallest wooden tower in France.</p>

<p>In light of global environment issues, the authors proposed a building system comprising steel and timber structure (Hereafter referred to as CSTS), which consist of rolled-H section steel and timber. The CSTS is assumed to adapt for mid-rise story building steel structures. It is a design method of the CSTS that uses the concept of a damage-controlled structure characterized by using buckling-restrained braces as a seismic response control member. It is assumed to use materials such as a cross laminated timber(CLT) for floor structure of the CSTS. The hysteresis model of the CSTS is established based on the available experimental data. Assuming practicality, bending test of the composite steel-timber beam members jointed by bolts is conducted. Behaviour of the composite steel-timber beam members affected by different intervals of bolted joints is evaluated.</p>