This study investigates frame corner joints built of birch plywood plates and glulam elements connected via self-tapping screws. Analytical calculations based on the fastener group’s torsional moment ...resistance, the proposed fastener group’s elastic and post-elastic load-bearing criteria, and the design formulas in Eurocode 5 were performed to predict the connection capacity in both elastic and post-elastic stages. A combined action check formula was adopted to predict the capacity of birch plywood plates and glulam elements. Frame corner specimens constructed with three different plywood thicknesses were planned to study the influence on global behavior and rotational stiffness. The specimens were intentionally designed so that failure occurred either in plywood or in glulam, in order to examine the robustness and validity of analytical calculation models. Another supplementary test group with 21 mm plywood and fewer fasteners was also designed and tested, in which the plastic yield of fasteners was expected. The test results of this supplementary group served to calibrate the analytical model that predicts the elastic and post-elastic capacity of the connection group. As a result of the comparison, the analytical calculations gave reasonable predictions on the failure of plywood, glulam, and the capacity of the fastener group. Only when the exposed moment exceeded the post-elastic limit of the fastener group did the plastic yielding of fasteners become observable. Moreover, numerical finite element models adopting the foundation zone-modeling scheme were constructed, which were proven to capture all test configurations' linear loading stiffness satisfactorily.
•Frame corner joints consisting of birch plywood, glulam elements, and self-tapping screws were constructed and tested.•Analytical models based on combined load action checks were able to predict the failure capacity of timber elements.•Analytical models based on polar moment of inertia well-predicted fastener groups' elastic and post-elastic capacities.•Global mechanical behavior and rotational stiffnesses were measured and compared among different test configurations.•The numerical model well-predicted the stiffnesses of frames with 21 mm plywood and underestimated that with thin plywood.
•Novel empirical hysteresis model based on a data-model driven approach.•First data-driven approach in modelling the hysteresis of timber-based structures.•The experimental cyclic response is needed ...for the model formulation.•A step-by-step optimization problem defines the evolution of the backbone curve.•The maximum displacement during the cycle is the hysteretic evolutionary parameter.•Publication of the MATLAB and Python code implementations of the hybrid hysteresis model.
This paper presents a novel computational approach to empirical hysteresis modelling applied to timber-based structures based on a combined data model-driven strategy. While the backbone curve is simulated using the experimental cyclic response based on a step-by-step optimization problem (data-driven approach), analytical functions describe the re-loading curves (model-driven approach). Empirical hysteresis models developed so far for timber structures are model-driven. However, the backbone curves can exhibit a highly irregular non-smooth trend, difficult to mirror using analytical formulations. The challenge in mirroring the experimental backbone using closed-form formulations has led to an extended set of parameters to be calibrated in existing literature models This paper presents a novel approach to the empirical hysteresis model, where the experimental data are directly involved, as a whole, in the model formulation. This model aims to be a possible trade-off between model complexity and accuracy. A reduced number of parameters needed to describe the re-loading paths is counterbalanced using an entire subset of the experimental data. The paper delivers the developed Matlab and Python codes for further implementation as a user-defined element within a Finite Element software.
•A novel modified engineered wood product, namely, plywood made from acetylated birch veneers.•Exhaustive dataset of mechanical properties of acetylated birch plywood in tension, compression, panel ...shear, and edgewise bending.•Significant angle dependence of the presented strength and elastic properties.•Comparison with ordinary unmodified birch plywood regarding strength, stiffness and failure modes.
There is an increasing demand for engineered wood products (EWPs) due to the flourish of modern timber structures during recent years. However, the durability-related issues are still unignorable limitations when applying timber to outdoor structures. Therefore, treatment measures are still needed to enhance the durability of timber. The acetylation process, which involves the reaction between acetic anhydride and wood, has been widely studied as a wood modification method during the past decades. Several experimental studies have proven acetylation to effectively reduce wood's hygroscopicity while improving its dimensional stability and fungal decay resistance. For load-bearing timber structures, especially those in the outdoor environment, the combination of acetylation and EWPs gives the possibility to manufacture more durable and stable timber elements in the context of dimensions and mechanical properties. This study concerns the mechanical and elastic properties of acetylated birch plywood. More specifically, tensile, compressive, shear and bending tests were conducted under three different load-to-face grain angles, namely from 0° (parallel), 22.5°, to 45°. The test results were thereafter compared with ordinary unmodified birch plywood concerning stress–strain relationships, failure modes, strength, and elastic properties.
Zukunft Bestand is a holistic concept for the ecological and socially inclusive renovation of existing housing complexes. Using two case studies representative of typical building methods of the 20th ...century, the book shows how measures a) preserve and inclusively improve existing structures, b) carefully integrate anything new, c) save resources and use them sensibly. The eco-social transformation, presented in the scales of settlement, building and detail, is therefore applicable to a large number of housing complexes in Austria and beyond.
Zukunft Bestand ist ein Gesamtkonzept für die ökologische und sozial inklusive Sanierung bestehender Wohnhausanlagen. Das Buch zeigt anhand von zwei Fallbeispielen, die repräsentativ für typische Bauweisen des 20. Jahrhunderts sind, wie Maßnahmen a) Bestehendes erhalten und inklusiv verbessern, b) Neues behutsam integrieren, c) Ressourcen schonen und sinnvoll einsetzen. Die in den Maßstäben Siedlung, Gebäude und Detail dargestellte ökosoziale Transformation ist somit auf eine Vielzahl von Wohnhausanlagen in Österreich und darüber hinaus anwendbar.
Adhesive bonding plays a pivotal role in timber engineering, enhancing structural integrity, sustainability, and aesthetic appeal, while also addressing environmental concerns. The assessment of ...strength in adhesively bonded timber joints involves cohesive strength, adhesive strength, and substrate failure, all of which are crucial considerations for designing dependable timber structures. A comprehensive investigation was carried out with the aim of improving adhesive bonding for construction by revealing the relationship between curing progress and mechanical adhesive properties. For that, dynamic DSC measurements, kinetic modelling, tensile tests to determine the cohesive and adhesive strength, as well as tests for the evaluation of stiffness and hardness were performed using a two-component polyurethane adhesive. The investigation yielded valuable insights, particularly regarding the time- and temperature-dependent development of the curing degree and the aforementioned material properties. Additionally, the correlation between the curing degree and the respective material properties could be determined, showing that cohesion and stiffness built up occurs quite similar while the build-up of adhesive strength correlates well with hardness. It was thus concluded that Shore D hardness might represent a practical indicator for monitoring the progress of curing at low temperatures, which is a suitable means of improving adhesive applications in the construction industry.
•Pseudo-static cyclic tests on Cross-Lam Timber (CLT) and Light Timber Frame (LTF) shear walls.•Decomposition of the post-elastic displacement into sliding, rocking and deformation ...components.•Similarity of the two structural responses due to the same resisting mechanism.•A capacity model based on the sole hold-down reaction seizes the overall cyclic response.•The estimated overstrength factors manifests the intrinsic differences between the two structural systems.
Cross Laminated Timber (CLT) and Light Timber Frame (LTF) shear walls are widespread constructive technologies in timber engineering. Despite the intrinsic differences, the lateral response of the two structural systems may be quite similar under specific connection layouts, boundary constraints, and size of the shear walls. This paper compares the experimental cyclic responses of CLT and LTF shear walls characterized by the same size 250×250cm, and loaded according to the EN 12512 protocol. The rigid-body rotation of the shear walls prevails over the deformation and rigid-body translation in the post-elastic displacement range. As a consequence, a capacity model of the two systems based on the sole hold-down response accurately seizes the observed cyclic response, despite ignoring the other resisting contributions. The authors examine the differences exhibited by the CLT and LTF shear walls and the related error corresponding to a capacity model based on the sole hold down restraints. Additionally, it is assessed the overstrength of the CLT panel and LTF sheathing to the shear walls collapse due to the hold-down failure. The estimated overstrength factor is the most meaningful difference between the two structural systems in the considered experimental layouts.
Friction-based dampers are a valid solution for non-invasive seismic retrofitting interventions of existing structures, particularly reinforced-concrete (RC) structures. The design of friction-based ...dampers is challenging: underestimating the slip force prevents the full use of the potential of the device, which attains the maximum admissible displacement earlier than expected. By contrast, overestimating the slip force may cause delayed triggering of the device when the structure has suffered extensive damage. Therefore, designing the appropriate slip force is an optimization problem. The optimal slip force guarantees the highest inter-story drift reduction. The authors formulated the optimization problem for designing a specific class of friction-based dampers, the asymmetric friction connection (AFC), devised as part of the ongoing multidisciplinary Horizon 2020 research project e-SAFE (Energy and Seismic AFfordable rEnovation solutions). The seismic retrofitting technology involves the external application of modular prefabricated cross-laminated timber (CLT) panels on existing external walls. Friction dampers connect the CLT panels to the beams of two consecutive floors. The friction depends on the mutual sliding of two metal plates, pressed against each other by preloaded bolts. This study determines the optimal slip force, which guarantees the best seismic performance of an RC structural archetype. The authors investigate the nonlinear dynamic response of a coupled mechanical system (RC frame-friction damper) under a set of strong-motion earthquakes, using non-differential hysteresis models calibrated on the experimental cyclic responses. The solution of the optimization leads to the proposal of a preliminary simplified design procedure, useful for practitioners.
•e-CLT is a seismic retrofit system for RC frames developed within Horizon 2020.•Proposal of a simplified design strategy for e-CLT.•Modeling of the response of an RC frame equipped with the e-CLT friction connection.•Experimental tests and calibration of a Coulomb-like hysteresis model.•Optimization of the slip force in the friction connection.•The optimum slip is associated with the yielding displacement of the RC frame.
While the manufacturing industry in Europe is looking at Industry 4.0 approaches and technologies to maintain the current competitive advantage, on the other hand, in the building industry (BI) they ...may push an improvement of the overall productivity also. This paper presents a research activity, which has aimed at investigating potentials and criticisms of Parametric and Generative Design techniques in mass-production environments of the BI though a pilot-case-study analysis in Glued-Laminated-Timber (GLT) industry. Starting from programming a parametric algorithm for GLT engineering, the research has measured manufacturing effectiveness and manufacturing efficiency through a Value-Stream Map of an ordinary supply-chain system of GLT. Considering all the limits of referring to a single case study, results highlight improvements both in manufacturing effectiveness and manufacturing efficiency; but limitations have to be considered as well, due to the complete absence of Industry 4.0 approaches and technologies in an ordinary supply-chain system of GLT.
•Application of Parametric and Generative Design techniques in mass production environments of the Building Industry•Development of a pilot case study in the Glued-Laminated-Timber (GLT) Industry•Analysis of impacts implementing a parametric algorithm in an ordinary value-chain system of GLT•Testing the effectiveness of a parametric algorithm for product design and engineering through Value-Stream Modelling•The paper highlights needs of Industry 4.0 approaches and technologies in order to overcome actual limitations
The authors present a novel transcendental hysteresis model based on the piecewise definition of arctangent functions. The definition of the shape parameters of the arctangent functions originates ...from the features of the experimental hysteresis curves directly. In the first step, the authors present this model's application to the experimental cyclic response of cross‐laminated timber (CLT), light‐timber frame (LTF) shear walls, and a steel angle bracket. Then, the response of a plywood‐coupled laminated‐veneer lumber (LVL) shear wall is used for validation purposes. The paper introduces the arctangent‐based model, labeled Atan model, by illustrating some possible shortcomings of hysteresis models with pinching. The paper concludes with a simple demonstration of these issues in the case of a Bouc‐Wen class hysteresis model, the extended energy‐dependent generalized Bouc‐Wen (eegbw) model. The numerical instabilities of the eegbw model are used to endorse the advantages of the proposed formulation in modeling complex structural arrangements, like wood joints and structural systems. The proposed model originates from the analysis of the experimental response of wood joints. However, it can be of more general application, and the particular reference to wood joints does not preclude other application fields.
This book provides guidance on the design of timber buildings for fire safety, developed within the global network Fire Safe Use of Wood (FSUW) and with reference to Eurocode 5 and other ...international codes. It introduces the behaviour of fires in timber buildings and describes strategies for providing safety if unwanted fires occur. It provides guidance on building design to prevent any fires from spreading while maintaining the load-bearing capacity of structural timber elements, connections and compartmentation. Also included is information on the reaction-to-fire of wood products according to different classification systems, as well as active measures of fire protection, and quality of workmanship and inspection as means of fulfilling fire safety objectives. Presents global guidance on fire safety in timber buildings Provides a wide perspective, covering the whole field of fire safety design Uses the latest scientific knowledge, based on recent analytical and experimental research results Gives practical examples illustrating the importance of good detailing in building design Fire Safe Use of Wood in Buildings is ideal for all involved in the fire safety of buildings, including architects, engineers, firefighters, educators, regulatory authorities, insurance companies and professionals in the building industry.
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