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This paper reviews recent developments of the mechanical models and formulations for the embedment of traditional timber joints in Japan. In recent decades in Japan, seismic performance evaluation methods of traditional timber buildings have been actively researched, and useful findings have been obtained to evaluate the seismic performances of traditional timber buildings such as temples, shrines, and dwelling houses. The major seismic resisting elements of traditional timber buildings in Japan are restoring forces of thick column rocking, rotational resistances of column‐beam joints, and shear resistances of mud/wood walls. Among them, the restoring force of rotational resistances of column‐beam joints due to embedment plays an important role. Such restoring force characteristics depend primarily on the partial compression on continua. However, the partial compression on continua is difficult to analyze owing to the continua. In relation to the partial compression on continua, research results of beams on elastic foundations are reviewed. Subsequently, the recent developments of mechanical models and formulations of the traditional timber joints in Japan are reviewed and problems related to formulations are discussed, and the authors' comments are given.

This work presents the development of a three-dimensional lattice material model for wood and its application to timber joints including the potential strengthening benefit of second order effects. A lattice of discrete elements was used to capture the heterogeneity and fracture behaviour and the model results compared to tested Sitka spruce (Picea sitchensis) specimens. Despite the general applicability of lattice models to timber, they are computationally demanding, due to the nonlinear solution and large number of degrees of freedom required. Ways to reduce the computational costs are investigated.Timber joints fail due to plastic deformation of the steel fastener(s), embedment, or brittle fracture of the timber. Lattice models, contrary to other modelling approaches such as continuum finite elements, have the advantage to take into account brittle fracture, crack development and material heterogeneity by assigning certain strength and stiffness properties to individual elements. Furthermore, plastic hardening is considered to simulate timber embedment.The lattice is an arrangement of longitudinal, lateral and diagonal link elements with a tri-linear load-displacement relation. The lattice is used in areas with high stress gradients and normal continuum elements are used elsewhere. Heterogeneity was accounted for by creating an artificial growth ring structure and density profile upon which the mean strength and stiffness properties were adjusted.Solution algorithms, such as Newton-Raphson, encounter problems with discrete elements for which ’snap-back’ in the global load-displacement curves would occur. Thus, a specialised solution algorithm, developed by Jirasek and Bazant, was adopted to create a bespoke FE code in MATLAB that can handle the jagged behaviour of the load displacement response, and extended to account for plastic deformation.The model’s input parameters were calibrated by determining the elastic stiffness from literature values and adjusting the strength, post-yield and heterogeneity parameters of lattice elements to match the load-displacement from laboratory tests under various loading conditions.Although problems with the modified solution algorithm were encountered, results of the model show the potential of lattice models to be used as a tool to predict load-displacement curves and fracture patterns of timber specimens.

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies, 12, 9, 12A9C: 1-8

The aim of this PhD is to propose a numerical modelling engineering tool for the design of dowelled timber joints with in-plane loading (N, M, V). It is part of a context where the needs of the engineers for the design of these kind of joints are increasing, in particular on the connection stiffness estimation and the load distribution. A three-dimensional model of an elastoplastic beam on non-linear supports was chosen as the basis for development in order to model the local mechanical behaviour of the dowel-wood interaction. These nonlinear supports are used to describe the embedment behaviour of the dowel in the thickness of the timber members. Embedding tests on several materials and dowel diameters were carried out to characterize this behaviour. Methodology to analyse embedment test curves was proposed to be in line with the model used. Within the framework of a European collaborative work, this methodology was used on experimental results from four research laboratories in order to provide a database. The database analysis has made it possible to find some empirical correlations to estimate physical parameters related to the embedment. The proposed modelling is developed using the Cast3M finite element calculation code. It integrates all the material behaviours of the joint components. It gives an accurate estimate of the load distribution of the joint generated by in-plane loading, as well as the axial and rotational stiffnesses. The numerical model has revealed the influence of the dowel slenderness on the connection stiffness estimation.; Ce travail de doctorat a pour objectif de proposer un outil ingénieur de modélisation numérique pour le dimensionnement d’assemblage de structures bois de type tige sollicités dans leurs plans (sollicitations N, M, V). Il s’inscrit dans un contexte où les besoins de l’ingénieur pour le dimensionnement de ce type d’assemblage, en particulier sur l’estimation de la raideur et de la distribution des efforts, sont croissants. Un modèle tridimensionnel de poutre élastoplastique sur des appuis non linéaires a été retenue comme base de développement afin de modéliser le comportement mécanique local de l’interaction organe-bois. Ces appuis non linéaires servent à décrire le comportement en enfoncement de l’organe dans l’épaisseur des éléments bois. Des essais d’enfoncement sur plusieurs matériaux et diamètres d’organe ont été réalisés pour caractériser ce comportement. Une méthodologie d’analyse de courbes d’essai d’enfoncement a été proposée pour être en adéquation avec le modèle utilisé. Dans le cadre d’un travail collaboratif européen, cette méthodologie a été utilisée sur des résultats expérimentaux de quatre laboratoires de recherche afin de constituer une base de données. L’analyse de cette dernière a permis de proposer différentes équations empiriques pour estimer des paramètres physiques de l’enfoncement. La modélisation proposée est développée à l’aide du code de calcul aux éléments finis Cast3M. Celle-ci intègre tous les comportements matériels de l’assemblage. Cela donne une estimation précise de la distribution des efforts des organes de l’assemblage générée par des sollicitations planes, ainsi que les raideurs axiales et rotationnelles. La modélisation a mis en évidence l’influence de l’élancement de l’organe dans l’épaisseur de l’assemblage sur l’estimation de la raideur d’assemblage.

This paper proposes a numerical model capable of predicting the mechanical behaviour and the failure mechanism of typical wall-to-floor connections for Cross-Laminated Timber structures. Such systems are assembled with angle brackets and hold-downs, anchored to the wall and floor panels with profiled nails and bolts. The metal connector and the elements to which it is fastened are modelled using 3D solid bodies, while the steel-to-timber joints are simulated as non-linear hysteretic springs. Shear and tension tests are reproduced on two connection systems and results are compared to the test data obtained from similar configurations. Simulations lead to accurate predictions of the mechanical behaviour (i.e. elastic stiffness, maximum load-carrying capacity, and shape of the hysteresis cycles) and energy dissipation. Finally, the performance when lateral and axial loads are applied simultaneously is investigated. Analyses are carried out by varying the inclination of the load, with respect to the axis of the connector, between 0° and 90°. Results exhibit a quadratic interaction relationship between shear and tension loads, and prove that their coupled effect influences the stiffness and the maximum load-carrying capacity.

In the field of timber engineering, adhesive bonding remains a promising, though poorly developed, joining technique that may increase the structural stiffness and capacity of timber joints and structures. Selecting ductile adhesives may further allow to conceive ductile joints, which can compensate for the missing material ductility of timber. To demonstrate the potential of this approach, adhesively bonded double-lap timber joints were manufactured using a ductile acrylic adhesive and then subjected to axial tension and compression. The load–displacement responses were captured and compared to those of the same joints composed of a brittle epoxy adhesive. The effect of the different adhesives on the joint ductility has been studied and quantified.

Self-Tapping Screws (STSs) are commonly used to realize many geometrical configurations for connections that are characterized by enhanced stiffness and load-carrying capacity. The analysis of STS joints and composite systems, however, usually requires designers to account for several aspects in their actual load transfer mechanisms, and most of them require refined calculation tools. In this paper, an extended Finite Element (FE) investigation is proposed for timber-to-timber slabs with STS joints, based on full 3D brick models inclusive of Cohesive Zone Modelling (CZM) techniques and damage constitutive laws for the materials in use. The final goal of the study takes advantage of the global and local performance assessment of a selection of STS joints, with careful consideration for their response under a conventional Push-Out (PO) test setup or a full-size bending configuration. As shown, major FE outcomes are discussed to elaborate a design procedure that can be developed on the base of correlation coefficients for maximum force and stiffness calculations in a given slab and loading condition. Major effects due to variable loading configurations are in fact explored at the screw level. Further, geometrically simplified spring-based FE models, that hardly capture the complex behaviour of the examined systems but are largely used in design practice, are presented in comparison to refined FE approaches and literature efforts. As shown, the variation of maximum force and stiffness parameters for STSs is emphasized in the paper for a selection of configurations, and fitting curves are proposed to estimate the STS performance along a given full-size slab, thus suggesting the feasibility and possible generalization of the procedure.

Large span timber trusses are usually built with glulam. One problem with large span glulam trusses is that the connections needed to transfer the load between truss members are often complex and expensive. Another issue is transportation. Building large span trusses out of structural timber instead, could be a way of simplifying the connections and at the same time increase the degree of on-site construction and thereby solving the transportation problem.In this study, a total of 18 laboratory tests were performed with the purpose of investigating the tensile strength and the load slip behavior of different connection designs for large span structural timber trusses. Six different test groups corresponding to six different connection designs were tested. The materials used include members made of C24 timber and gusset plates made of birch plywood, aluminum, and steel. Screws were used as fasteners for five test groups and adhesive was used for one group. The influence of different reinforcement techniques including reinforcement screws and added aluminum sheets was studied.The results showed a ductile failure behavior for all test groups except for the group where adhesive was used. However, a decrease of ductility was observed for groups were aluminum sheets were used on the outsides of the mid placed plywood gusset plate. A 12-17 % increase in capacity was observed due to the presence of aluminum sheets. The reinforcement screws had no significant effect on the capacity. However, the presence of reinforcement screws did lead to a reduction in scatter both regarding capacity and stiffness.

In this paper, a Finite-Element (FE) numerical investigation on timber-to-timber joints and composite beams with inclined self-tapping screws (STSs) is presented. Based on past experimental data and numerical literature efforts, full 3D solid FE models of selected geometrical and mechanical configurations of technical interest are implemented in ABAQUS software package and analysed under static loading conditions . The typical push-out samples include GL24h timber members with several types (WT-T-8.2, 190 mm and 220 mm their length), layouts (2 + 2, 4 + 4, 2 + 2 X-shaped) and inclination of screws (up to ±45°). For the full-scale beam samples in bending (8 m their span), composite systems consisting of GL24h timber beam, wooden plank, spruce floorboards and STSs are investigated. There, the STS joints take the form of two-rows or X-shaped connections, respectively (45° or 90° their inclination), including four screw types and different spacing. In both the push-out and full-scale cases, simple modelling approaches are taken from the ABAQUS library and adapted to the timber-to-timber structural system under investigation, so as to explore their structural performance in the elastic and post-damage phases, up to failure. A key role in the typical FE models is assigned to input material properties and mechanical contacts, including damage constitutive laws so as to reproduce possible local failure phenomena in the timber or steel components, as well as cohesive damage interactions for the joints. The presented FE models are calibrated in accordance with past research studies, and validated – for the examined structural typology – against experimental results available in literature. Comparative calculations are hence presented, based on the collected numerical, experimental and analytical estimations for the selected samples. As shown, the examined modelling approach can reasonably capture the expected performance of timber-to-timber joints and composite systems.

Self-tapping screws (STS) are largely used in timber construction, both for fastening and rein-forcements. Their continuous thread with high withdrawal capacity makes possible to construct many geometrical configurations for connections with stiffness and load-carrying capacity marked-ly higher with respect to traditional timber-to-timber joints. The arrangement of screws with differ-ent inclination and spacing, however, requires the designer to account for several aspects in the actual load transfer mechanism of the full connection, including the bending capacity of screws, the embedment strength of wood, the withdrawal capacity of fasteners, as well as friction between the system components. In this paper, an advanced Finite Element (FE) numerical study is proposed for novel hybrid connections. As known, FE analyses can offer a robust support to design en-hancements, as an alternative to costly and time consuming experimental testing. On the other side, complex mechanical behaviors that are typical of composite structural systems can be hard to cor-rectly reproduce, due to a combination of multiple aspects. Major advantages of the current re-search study are taken from small-scale and full-scale experimental tests carried out on a wide set of geometrical and mechanical configurations. As shown, a key role for the discussed FE investiga-tion is assigned to the reference modelling approach. While the material properties are properly taken into account (including possible damage evolution in the steel and timber components of in-terest), special care is spent for a set of contact interactions, based on the use of the Cohesive Zone Modelling (CSM) method and its adaptation for timber-to-timber composite systems. The reliability of FE results is then discussed, towards the development of a robust generalized modelling ap-proach that could be used in support of the refined analysis and design of hybrid connections in timber-to-timber composite slabs.

The mechanical behaviour of steel-to-timber joints with annular-ringed shank nails is investigated using numerical modelling and a component approach. These joints are used in Cross-Laminated Timber (CLT) buildings to anchor metal connectors such as hold-downs and angle brackets to the timber panels. At first, a general hysteresis model is introduced, where a single fastener joint is schematized as an elasto-plastic beam embedded in a non-linear medium with a compression-only behaviour. A second hysteresis model is then presented, where the mechanical behaviour of the joint is simulated by a non-linear spring with three degrees of freedom. Both models are calibrated on the design rules prescribed by the reference standards. Moreover, average strength capacities are determined from the corresponding characteristic values assuming a standard normal distribution and suitable coefficients of variation. As first applicative examples of the proposed models, shear tests are simulated on single steel-to-timber joints with annular-ringed shank nails and on a connection made of an angle bracket and sixty nails. The scatter of mechanical properties in steel-to-timber joints is also taken into account in the simulations and a stochastic approach is proposed, demonstrating acceptable accuracy.

The employment of timber pegs in timber structure joints is a widespread technology in the field of timber frame building in the United States, where the Timber Frame Engineering Council has published a special Standard to supplement the National Design Specification for Wood Construction. The authors have been studying the possibility of supplementing the Eurocode 5 design formulas, thought for timber joints with metal connectors, with specifications needed for a reliable design when employing timber pegs. The field of application envisaged is that of restoring timber structures and results obtained until now are quite encouraging. In this step of the research, more attention has been paid to deformation process: fir and chestnut samples have been tested to determine their dowel-bearing behavior with steel and ash timber peg while double-shear plane joints made of the same wood species, and fastened with steel as well as timber pegs, have been analyzed.

The research deals with a 49.0 mm in diameter mechanical fastener to which load perpendicular to grain is applied. The experimental research was divided in two series: the first series was carried out with locally reinforced, and the second with non-reinforced timber specimens. The local reinforcement of timber elements with textile sheets between lamellas in a layer of adhesive was made in the production process. Furthermore, research on finite element models using Abaqus/CEA software package was carried out. UMAT subroutine and cohesive contact between surfaces were used for modelling complex timber mechanical properties and cracks opening. The research results have shown that glass fiber textile placed between lamellas in adhesive layer effectively increases the resistance and splitting capacity of timber joint. Analytical approach has been proposed for predicting the splitting capacity of the reinforced joint.

This paper investigates the mechanical and the hysteretic behaviour of steel-to-timber joints with annular-ringed shank nails in Cross-Laminated Timber (CLT). These fasteners are used to anchor typical metal connectors, such as hold-downs and angle brackets, to the CLT panels. The experimental programme presented in the paper was carried out at the Institute of Timber Engineering and Wood Technology, Graz University of Technology (Graz, Austria). Average and characteristic values of the experimental strength capacities are evaluated and compared to the analytical predictions determined according to current structural design codes and literature. Furthermore, to fulfil the requirements of the capacity-based design, the overstrength factor and the strength degradation factor are evaluated and conservative values are recommended.

Double-shear steel-to-timber joints of beech laminated veneer lumber (LVL) with slotted-in steel plates using very high strength steel (VHSS) dowels have been investigated. Tensile tests on full-scale joints with one, two, three and six dowels have been carried out, using both VHSS and mild steel dowels. The goal of the research was to investigate the mechanical behaviour of joints of beech-LVL, with regard to load-carrying capacity (LCC), ductility, stiffness; and to find out whether the current design rules of Eurocode 5 are suitable for LVL and VHSS steels. Other examined aspects were the effect of multiple fasteners in a row and the influence of fastener steel grade. Tests showed higher values of joints with VHSS dowels, characterized generally by low scatter. The prediction ability of Eurocode 5 has been found to be inadequate and too conservative. A proposal for improvement is included.

Double-shear steel-to-timber joints of beech laminated veneer lumber (LVL) with slotted-in steel plates using very high strength steel (VHSS) dowels have been investigated. Tensile tests on full-scale joints with one, two, three and six dowels have been carried out, using both VHSS and mild steel dowels. The goal of the research was to investigate the mechanical behaviour of joints of beech-LVL, with regard to load-carrying capacity (LCC), ductility, stiffness; and to find out whether the current design rules of Eurocode 5 are suitable for LVL and VHSS steels. Other examined aspects were the effect of multiple fasteners in a row and the influence of fastener steel grade. Tests showed higher values of joints with VHSS dowels, characterized generally by low scatter. The prediction ability of Eurocode 5 has been found to be inadequate and too conservative. A proposal for improvement is included.

U radu su prikazana istraživanja na priključcima sa spojnim sredstvom promjera 49 mm. Istraživanja su provedena eksperimentalno na dvije grupe uzoraka: uzorcima s lokalnim ojačanjem drva u zoni spoja i bez lokalnog ojačanja. Uzorci su ispitani s unosom sile u spoj okomito na vlakanca drvenog elementa. Svrha provedenih istraživanja je analiza utjecaja količine tkanine na mehaničke karakteristike priključka. Obzirom da su eksperimentalna istraživanja provedena na lokalno ojačanim uzorcima sa 900 g/m2 tkanine, područje između ojačanih i neojačanih uzoraka nadopunjeno je rezultatima iz parametarske numeričke analize. Za numeričku analizu priključaka metodom konačnih elemenata rabljen je Abaqus/CEA programski paket. Za modeliranje kompleksnih modova otkazivanja, mehaničkih karakteristika i otvaranja pukotine u drvu korištena je UMAT podprogram i kohezijska interakcija između kontaktnih ploha. Rezultati istraživanja pokazali su da primjena tkanine čak i u najmanjoj količini povećava maksimalnu silu i silu popuštanja priključka., Research deals with a 49 mm in diameter mechanical fastener in reinforced laminated timber, to which a load perpendicular to grain is applied. Influence of glass fibre textile to reinforcing connection zone on the joint mechanical properties was carried out. The experimental tests were divided in two stages: first stage was carried out on locally reinforced and second on non-reinforced timber specimens. Finite element models were made in software package Abaqus/CEA ver. 6.10. UMAT subroutine and surface-based cohesive behaviour were used for modelling complex timber behaviour. Results obtained by finite element model and experimental tests were shown and compared for non-reinforced and reinforced specimens with 900 g/m2 of textile in connection zone. Also, parametric finite element model analyses were carried out for reinforced specimens with textile quantity between 0 ÷ 900 g/m2 in the connection zone. Research results have shown that the application of textile in connection zone increases maximum force and yield force even in the smallest quantity.

Timber is one of the primary building materials of today, both in Sweden and in Europe, its uses range from single-family homes to apartment buildings and large arenas. The key reasons why timber construction continues to grow is the environmental aspects combined with the economically advantageous industrialised prefabrication process. One of the most commonly used connections in timber structures is the punched metal plate fastener, which is a perfect example of an effective connection that only can be used in a prefabrication process. It can be found in almost all kinds of buildings; from a rafter connection in small to middle sized houses up to reinforcement in heavier connections in arenas and warehouses. It is well known that the connections are the most critical parts of a structure and it is therefore crucial that these are designed for all eventualities. This project is a pilot study that seeks to evaluate the existing design methods for punched metal plate fasteners subjected to fire in Eurocode and in practice. The first conclusion is that such a method hardly exists, neither in codes nor in scientific theory, despite the fact that this is and has for decades been a very common structural detail. The theoretical analysis shows that it is very unlikely that a joint made with punched metal plate fasteners can withstand a standard fire scenario for even 15 minutes and the small-scale testing confirms this. But the project also shows that it is possible to protect the punched metal plate fasteners from fire and that it is possible to achieve up to 30 minutes resistance by installing gypsum fireboards, stone wool wood covering. Validerat; 20121013 (anonymous)

The use of timber pins in connecting timber elements is a valid alternative to the employment of metallic devices, and apart from being quite spread in prefabricated timber frames, it could be an efficient solution in the field of restoring timber structures. The design rules for pinned joints are universally based on Johansen’s theory, (European Yield Model), but their application to timber pegged connections still shows some unsolved problems, linked to: 1) dowel-bearing strength; 2) bending strength of the pin; 3) shear strength of the pin; 4) the feasibility of the fourth failure Mode of EYM. Many studies analysing one or more of those aspects can be found in literature, but there isn’t yet an analytical formulation alternative to this on which the EYM is based. Authors are carrying on an extended experimental research, trying to better understand the complex mode of failure of timber joints connected by timber pegs, and consequently improving design rules. A first phase has involved double shear plane joints of glulam fir connected by ash pins, varying thickness of jointed board, pointing out the role of bending strength. In a second step the role of dowel-bearing strength has been investigated, choosing as base material three wood essences with quite different densities. Now the final step of the whole research is presented: first of all, the role of pin shear strength has been studied; then all obtained results are employed in analyzing the behaviour of double shear plane joints with varying timber essences and its transposition in using design rules.

The article discusses the main methods for steel threaded rods pasted into timber. Single – threaded steel rod carrying capacity glued onto glulam (timber cross section – 100 x 100 mm, threaded rod – M12 and M16) has been experimentally determined. Behaviour based on the experimental results of two different methods for pasting rods into timber has been summarized: the first threaded steel rod was glued into 4 mm bigger diameter hole while the second – rod chased into 2 mm smaller diameter hole. The conducted experiment used 800 mm length glulam beams; threaded steel rods were glued to both ends of specimens (equal theoretical carrying capacity). The experiment in the tension of both ends was carried out. The obtained results were compared with theoretical expressions submitted in EC 5 – 1 – 1:2005 and STR 2.05.07:2005. The main dependences of geometrical parameters and carrying capacity have been provided. The main collapse forms of specimens and manufacturing defects having influence on the final carrying capacity and behaviour of the joint have been observed. Using the first method, a failure in the pasted rod occurs suddenly when timber splits along the fibre; in the second case, a failure is plastic when timber is compressed under thread. Additional experiments must be carried out using the first technology increasing the class of the strength of the pasted rod as under the maximum length of paste, in all cases, failure in the pasted rod occurred when a steel bar cracked. Along with an increase in the diameter of the rod, the dispersion of the results of the affixed slender part is increasing. Maximum variation in the results of applying the first method is 10%, whereas the second method of attaching makes 50%. Compared to the first method of attaching, the results of theoretical bearing capacity indicate that tests have an adequate margin which is equal to or is more than 2,0. A comparison of the second method of attaching results to theoretical bearing capacity makes clear that the experimental results of the tests have too low safety factor and in some cases are less than 1.0. This is due to the fact that the counting of attaching technology in some cases must be based on local compressed timber strength. The experimental study of two different methods for attaching steel bars reveals that the first method can be used in design practice considering both documents STR 2.05.07:2005 and EC 5-1-1:2005. The second method of attaching must be developed to ensure smooth rod surface coating adhesive. Attaching the second method should also be created in the exact form corresponding to the disintegration of the calculation model. Article in Lithuanian. Jungties tarp įklijuoto plieninio sriegtojo strypo ir medienos elgsenos tyrimas Santrauka.Straipsnyje aptariami pagrindiniai plieninių sriegtųjų strypų įklijavimo medienoje metodai. Eksperimentais nustatytos pavienių plieninių sriegtųjų strypų (M12 ir M16), įklijuotų medienoje, jungčių laikomosios galios. Apibendrinta dviejų skirtingų įklijavimo metodų (pirmasis – strypas įklijuojamas į 4 mm didesnio skersmens kiaurymę; antrasis – strypas įsriegiamas į 2 mm mažesnio nei strypas skersmens kiaurymę) elgsena remiantis eksperimentinių tyrimų rezultatais. Pagrindiniam eksperimentui naudoti klijuotosios medienos elementai (skerspjūvio matmenys – 100×100, ilgis – 800 mm), kurių galuose lygiagrečiai su medienos pluoštu buvo įklijuoti sriegtieji plieniniai strypai. Atliktas abipusis tempimo bandymas apkrovą perduodant strypams. Eksperimentinių tyrimų rezultatai lyginami su teorinės laikomosios galios skaičiavimais, atliktais pagal Lietuvos ir Europos medinių konstrukcijų projektavimo normų taisykles. Pateiktos jungties laikomosios galios ir geometrinių parametrų priklausomybės. Aptartos pagrindinės bandinių suirimo formos ir gamybos netikslumai, turėję įtakos jungties laikomajai galiai. Reikšminiai žodžiai: medienoje įklijuoti strypai, įtempių pasiskirstymas medienoje, medienos jungtis. First Published Online: 16 May 2013

This study is part of a larger research devoted to the analysis of the behavior of timber joints connected with timber pins, which of course is quite different from that in presence of steel bolts. As in the last case design formulas are based on the Yield European Model, which involves mechanical characteristics of the dowel as well as of the timber elements constituting the joint, the whole research aims to the identification of similar properties in the case in hand. Specifically the present study analyzes, with an experimental approach, the dowel-bearing behavior when employing a timber pin instead of a steel connecting device. The final task is the definition of a procedure to identify the value of the dowel-bearing strength of the jointed elements' timber to be inserted in design formulas, going through the understanding of the role of the timber pin behavior when confined inside the joint and its influence on the dowel-bearing behavior.

Baigiamajame magistro darbe pateiktos pagrindinės prielaidos, kurios priimamos analizuojant klijų kontaktą tarp medienos ir metalo. Aptartos plačiausiai taikomos plieninių sriegtų strypų įklijavimo medienoje technologijos. Apibendrinti plieninių sriegtų strypų įklijavimo medienoje technologijos kontrolės metodai. Išanalizuota mokslinė literatūra, susijusi su plieninių sriegtų strypų įklijavimu medienoje. Tiriamojoje dalyje surasti ir išnagrinėti Pasaulinės patentų sistemos „esp@cenet“ 11 patentų, kuriuose pateikiami montažiniai medienos elementų mazgai, sukonstruoti panaudojant plieninius įklijuojamus strypus. Pateikti pagrindiniai standžių montuojamųjų mazgų konstravimo principai. Eksperimentinėje dalyje laboratoriniais bandymais ištirta sąveika tarp medienos ir plieninio sriegto strypo, kai kontaktas tarp jų užtikrinamas klijais. Atlikti eksperimentiniai tyrimai: plieninių sriegtų strypų takumo bei stiprumo įtempių nustatymas; medienos tankio ir drėgnio nustatymas; plieninių sriegtų strypų ištraukiamojo atspario nustatymas. Aptarti pagrindiniai gamybos netikslumai, kurie turi įtakos jungties elgsenai ir laikomajai galiai. Išanalizuota pavienio plieninio strypo, įklijuoto medienoje, gniuždomojo ir tempiamojo atspario skaičiavimo metodika, pateikiama projektavimo normose STR ir Eurokode 5. Bandymų rezultatai palyginti su teorinėmis išraiškomis, pateikiamomis projektavimo normose. Remiantis eksperimentinių bandymų rezultatais ir ankstesnių autorių tyrimų... [toliau žr. visą tekstą] In this master degree thesis submitted general assumtions which are being adopted while analysis of glued joint between timber and steel. Discussed the main technologies of glueing in steel rod into timber. Summarized technolgy control methods of glueing in steel rods process. Overviewed the scientific literature which is related to the steel rods glued in timber. In research part of the work submitted 11 patents of esp@cenet patent base of rigid joints in which construction used glued in steel rods. Given the main principles of construction of rigid joints with glued in steel rods. In experimental part of the work investigated the behavior of the timber – steel joint which contact is ensured by glue. Experimental studies were done: yield and strength stress determination of threaded steel rods; determination tests of timber moisture content and density; determination of tensile carrying capacity of threaded steel rod glued in glulam. Reported production inaccuracies and its influence on joint‘s behavior and final carrying capacity. The results are compared with theoretical expressions provided by the design rules. Based on the experimental results of the test and study reports of previous authors, submitted proposals for design rules of the addition of comments. Structure: introduction, the concept of the matter, literature review, experimental studies, conclusions and suggestions, references. Thesis consist of: 100 p. text without appendixes, 64 pictures, 20 tables, 43... [to full text]