This paper focuses on the newly proposed RC-CLT hybrid wall systems used in residential buildings. Cyclic loading tests were conducted using 2-storey specimens, to confirm the seismic performance and ...behavior of the hybrid system and also to investigate the behavior of the RC beams in mid-level and the transmission of shear stress by the CLT wall from upper to lower level. The experimental results showed that CLT could potentially be more superior than RC wall infill in terms of ductility, due to CLT exhibiting higher inter-story drift during shear failure. Furthermore, this study proposes numerical models to simulate the experimental results of the hybrid systems. The RC structural members were modeled using linear elements with MS model inserted at the ends to consider for the N-M interactions. As for the CLT wall, it was modeled using several braced models. The numerical results generally show good agreements with the experimental results. As a result, the numerical model proposed in this study can contribute to better predict the structural behavior of CLT shear wall infilled RC frame with concealed steel plate and drift pin connections.
•Seismic performance and behavior of 2-storey newly proposed RC-CLT hybrid wall systems.•Formation of yielding mechanisms in the RC frames and trend of shear and vertical force transmissions in the CLT shear wall.•Proposal of numerical model for the RC-CLT hybrid wall system and comparison with the experiment results.
Cross laminated timber panels (CLT) are promising building structures that are actively used in the construction of buildings around the world. In Russia the construction is rarely used, despite the ...existing factories for their manufacturing. In regulatory documents there are no specific data on the elastic modulus for these structures. As a method for determining this calculated characteristic, a numerical experiment in the SCAD Office software package is proposed. During the experiment, panels of various thickness and different numbers of layers are considered. Based on the obtained displacements from the action of the applied load, the values of the elastic modules are determined and summarized in the table. According to the results of the calculation, graphs of dependences of the reduced elastic modules on the thicknesses and the number of layers are constructed and analyzed.
•The coupled axial-shear behavior of angle bracket is considered in the formulation.•An experimental campaign was specifically designed on CLT panel-AB connections.•Monotonic and cyclic behavior of ...CLT panel-AB connections system are simulated.•Degradation phenomena due to cyclic loading are considered.
This paper presents an enhanced coupled axial-shear model for the monotonic and cyclic behavior of Cross Laminated Timber (CLT) panel – angle bracket connections. The proposed model accounts for the degradation phenomena due to cyclic loading that may affect strength, unloading and re-loading stiffnesses. The main parameters necessary to define the constitutive laws of the model are evaluated by linear regression analyses performed on the data obtained by an extensive experimental campaign specifically designed and carried out at the University of Bologna on CLT panel – angle bracket connections. After the first phase of model calibration, a comparison between numerical and experimental results from both monotonic and cyclic test series are performed to validate the model. These analyses demonstrate the effectiveness of the proposed model in representing the coupled response of angle bracket connections under simultaneous application of axial and shear forces.
Introduction. The article considers the prerequisites for the development and application of new construction technology with the use of renewable natural resource — wood. The problem of providing ...construction with raw materials for production is relevant. Objectives of the research — determination of the main advantages and disadvantages of CLT-panels as a material used in load-bearing frames; feasibility of CLT-panels in relation to other traditional building materials; identification of the main technological features of construction production with the use of cross-glued panels technology, determination of the advantages of the technology; necessity of research activities on the construction material for updating the relevant building regulations; analysis of foreign experience in the field of construction of wood-based panels.Materials and methods. The review and analysis of domestic and foreign literature, scientific papers, normative documents, information sources on the basis of eLIBRARY.RU were performed. Comparison and systematization of the obtained data. Earlier studies were also taken as a basis.Results. On the basis of the conducted analysis of information sources the description of the main properties and characteristics, as well as production technology of CLT-panels is given; positive and negative sides of the material application, advantages of construction technology of building frames erection are determined. The comparative analysis of domestic and foreign experience in wooden house building is carried out. The problems of cross-glue panel technology development in Russia are defined.Conclusions. The results obtained through the conducted research determine the feasibility of using CLT-panels as a building material for load-bearing structures, characterized by the presence of a list of properties significant for the industry: environmental friendliness, renewability, high rates of work production, reduction in the cost of construction of objects due to the reduction of labour intensity of the construction process.
•Timber panel to masonry pier screw connection for shear wall strengthening.•64 specimens in 16 configurations tested under in-plane shear loading conditions.•Monotonic, semi-cyclic, cyclic loading ...protocols for seismic behaviour assessment.•Examined parameters: masonry type, timber panel, screw anchor, load-to-grain angle.•Log-normal distribution data-fitting for maximum load and slip modulus.
The mechanical coupling of timber products to the masonry walls of unreinforced masonry (URM) buildings is generating considerable interest in terms of seismic vulnerability mitigation. An extensive experimental investigation on timber panel to masonry wall connections realised with screw anchor fasteners is presented. A total of 64 shear tests under monotonic, cyclic and semi-cyclic loading conditions were performed on site in a historic URM building. The examined parameters were: masonry type, timber panel product and material, load-to-grain direction, fastener geometry and steel grade. The outcomes of the campaign are then reported and discussed focusing on the strength and stiffness properties and on the dissipation capacity and residual strength of the connection under cyclic load. Moreover, a log-normal distribution fitting is proposed for the maximum load and slip modulus measurements of all the cyclic test configurations analysed. Finally, the principal experimental observations are listed along with recommendations for future work or use in practice.
•Timber-based floor strengthening solutions are reversible and minimally invasive.•Reinforced floors evidence an interesting in-plane stiffness and strength increase.•Some reinforced floor ...configurations maintain the load after several cycles.•The tests demonstrated a dissipative cyclic behaviour of reinforced timber floors.•Low-weight timber-based solutions can be alternative to the use of concrete topping.
Traditional timber floors in masonry buildings are characterized by low in-plane stiffness and lack of effective connections to the main walls, so the structure seismic performance is negatively affected and a reinforcement is often needed. In-plane dry strengthening solutions for timber floors in existing masonry buildings are faced: OSB panels or CLT panels were connected to 12 traditional full-scale timber floors and tested under monotonic and cyclic loads. The results of the tested solutions are compared to the unreinforced floor results. The whole experiment supports the effectiveness of this kind of strengthening intervention.
В статье авторами представлен анализ состояния жилищного фонда в различных регионах РФ, подверженных стихийным бедствиям. Показано, что в данных регионах наиболее перспективным является возведение ...зданий на основе модулей. Проанализирована возможность использования различных строительных материалов при возведении модульных зданий в разных климатических условиях. Приведена типология модулей, которые могут использоваться для формирования планировочных структур жилых зданий с выработкой особой многогранной структуры модуля. Разработаны объемно-пространственные и планировочные решения зданий разной этажности с использованием CLT-панелей на основе ствольной конструктивной системы. Сформирован визуальный ряд зданий на основе предложенной типологии модулей.
The Italian building heritage is aged and inadequate to the high-performance levels required nowadays in terms of energy efficiency and seismic response. Innovative techniques are generating a strong ...interest, especially in terms of multi-level approaches and solution optimizations. Among these, Nested Buildings, an integrated intervention approach which preserves the external existing structure and provides a new structural system inside, aim at improving both energy and structural performances. The research presented hereinafter focuses on the strengthening of unreinforced masonry (URM) buildings with cross-laminated timber (CLT) panels, thanks to their lightweight, high stiffness, and good hygrothermal characteristics. The improvement of the hygrothermal performance was investigated through a 2D-model analyzed in the dynamic regime, which showed a general decreasing in the overall thermal transmittance for the retrofitted configurations. Then, to evaluate the seismic behavior of the coupled system, a parametric linear static analysis was implemented for both in-plane and out-of-plane directions, considering various masonry types and connector spacings. Results showed the efficiency of the intervention to improve the in-plane response of walls, thus validating possible applications to existing URM buildings, where local overturning mechanisms are prevented by either sufficient construction details or specific solutions.
In-plane seismic behaviour of Cross-Laminated Timber (CLT) walls is influenced by panel-to-panel and panel-to-foundation mechanical connections, which consist of hold-downs and angle brackets. Due to ...the platform constructional technology, the orthogonal to grain timber-to-timber contact is also involved in the seismic response of the panels. To date, literature theoretical approaches to evaluating the flexural load-bearing capacity of CLT panels focus their attention on the schematization of hold-downs and angle brackets only, under evaluating the role of timber compressed in the perpendicular direction.
In this paper the influence of orthogonal to grain timber properties on the overall seismic behaviour of CLT walls has been investigated, proposing a general theoretical model to schematize the panel-to-panel and panel-to-foundation connections. A parabola-rectangle constitutive behaviour has been defined to describe the orthogonal to grain timber behaviour in the connection zones, while hold-downs and angle brackets are modelled adopting literature models. Five different failure conditions, described by mathematical formulations, able to describe the entire axial force-bending moment interaction domain have been defined.
The proposed model has also been employed to schematize the connection zones in multi-storey CLT walls with openings, allowing to investigate the effect of the orthogonal to grain properties on its seismic behaviour. Results of nonlinear analyses demonstrate a significant influence of orthogonal to grain timber properties on seismic behaviour of the walls, affecting their strength, stiffness, ductility and collapse mechanisms.
•The influence of the orthogonal to grain compression properties on seismic behaviour of CLT structures has been analysed.•A theoretical model to schematize the connection has been developed, accounting for orthogonal to grain compression.•Five different failure conditions describe the entire axial force-bending moment interaction domains of CLT panels.•The model has been employed to schematize the mechanical connection in multi-storey CLT walls subjected to seismic actions.•The importance of the orthogonal to grain compression effect on seismic behaviour of CLT walls has been highlighted.
In order to reach the ambitious decarbonizing goals set by the European Union for 2030, deep renovation of the existing European building stock is a key issue. Within this context, the recently ...funded H2020 project “e-SAFE” is investigating market-ready wooden envelope renovation solutions for non-historic buildings, which encompass both energy and seismic improvement. The research carried out in the project aims at developing, testing and demonstrating these solutions on a real pilot. More specifically, this paper presents preliminary analyses to verify that the solutions satisfy the requisites set by the national regulations in force in most European countries, in terms of hygrothermal and acoustic performance. The analysis, carried out following relevant technical European Standards and based on calculations, considers different climate conditions and existing wall structures, selected amongst those most commonly adopted in Europe. The results show that the addition of a Cross Laminated Timber (CLT) layer with some wooden-based insulation on the outer side allows reaching very good thermal and acoustic performance. However, interstitial condensation may occur in cold climates under high indoor humidity values. This aspect deserves further investigation accounting for the transient behavior of the walls and all vapor transport mechanisms.
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