Hybrid timber composites are becoming increasingly widespread to efficiently enhance timber performance. While carbon fibre reinforcement has been explored for strength in timber structures, its ...impact on vibration performance remains understudied and is crucial as mass timber buildings extend their spans and heights. This work explores the effect of carbon fibre reinforcement on the vibration performance parameters of CLT floor systems. Natural frequency, mode shape, damping and stiffness parameters are evaluated from experimental testing using the Natural Excitation Technique (NExT) combined with the Eigensystem Realization Algorithm (ERA) and robust techniques for selection of physical dynamic properties, verified against numerical finite element models. The findings reveal that, in the case of three-ply Cross-laminated Timber (CLT) panels with depths ranging from 115 mm to 135 mm, introducing reinforcement at ratios below 0.67% led to an enhancement in frequencies, registering an increase of 6% to 11%, although not explicitly accounting for changes in environmental conditions. Moreover, these reinforced panels showed a relevant increase in effective flexural stiffness, ranging from 15% to 22%, when compared to their unreinforced counterparts. This means an improved maximum span of around 4%–6% within current design limits for timber floors influenced by vibration performance. These findings enhance the understanding and design of high-performance composite timber floors, promoting the use of renewable building materials in construction.
•Stiffness of panels increase significantly with a small reinforcement ratio.•CFRP reinforcement allows for longer spans or smaller deflections while keeping the same panel thickness.•Floor-like assemblies also show an increase in natural frequencies due to the CFRP reinforcement.
•Increasing interest in the application of structural health monitoring.•Structural health monitoring and non-destructive testing for timber structures.•Case studies of monitoring of timber ...structures.•Survey about monitoring of timber structures.
Significant developments in structural health monitoring (SHM) and in non-destructive testing (NDT) and damage identification techniques for structural timber elements have led to an increasing interest in the application of these technologies. However, specific aspects of timber structures (anisotropy, moisture dependency, high variability), the wide range and novelty of available systems, and the need to adapt them for each configuration, makes specifying and implementing a SHM system a non-trivial task, heavily dependent on previous experience. This article presents a comprehensive review of available SHM and NDT methods, case studies, and a survey on the implementation of SHM in timber structures.
This work studies tensegrity bracing systems to be used as energy dissipation devices in next generation, earthquake-proof timber buildings. The examined lightweight and high-strength structures with ...re-centering capabilities are formed by timber members and pretensioned elements with a superelastic response, which may consist of shape memory alloy wires, cables or bars with energy dissipation capacity. In the case of bars, we assume that such members can be protected against buckling through their encasement in buckling-restrained devices, so as to respond both in tension and in compression. The work on the analyzed bracing systems presents novel results on this type of bi-directional response and the effects derived from the pretension of the superelastic elements, within an analytic formulation of the mechanical response of the structure. It includes an example dealing with a full-scale glued laminated timber frame, which compares the responses of different bracing systems in terms of the lateral force vs. drift ratio curve and ductility factor. The beneficial effects deriving from the use of buckling-restrained devices in an inverted V-braced timber frame are discussed. The presented results highlight the high potential of superelastic braces with tensegrity architecture for the design of timber frames exhibiting markedly high ductility ratios, which considerably surpass those of full-timber or timber-steel systems.
•An advanced FE non-linear modelling of X-Lam timber buildings is presented.•Shaking-table tests of X-Lam timber buildings were simulated with good results.•Parametric analyses on friction effect and ...strength domain in fasteners are shown.
This paper presents an advanced FE modelling of cross-laminated (X-Lam) timber buildings for non-linear dynamic analyses. The model has been used to reproduce the experimental results of the shaking table tests carried out in Japan within the SOFIE project on the 3- and 7-storey full-scale timber buildings. The X-Lam timber panels have been schematized with linear-elastic shell elements, whereas all metal connectors (hold-downs, angle brackets, screws) have been described with 3-DOFs non-linear hysteretic springs. The hysteretic law has a trilinear backbone curve, and is characterised by pinching, post-peak softening, strength and stiffness degradation. The approximating hysteretic laws of the springs have been calibrated on the experimental cyclic tests carried out on each single metal connector. Additional features of the model are the possibilities to account for friction at the interface between upper and lower X-Lam panels, and for a strength domain between shear and tensile force in the metal connectors. Due to the lack of experimental results, these variables have been identified via parametric study so as to reduce the difference between the numerical prediction and the experimental result of X-Lam single walls loaded with cyclic horizontal load. The experimental–numerical comparisons of the shaking table tests demonstrate the capacity of the model to capture the seismic responses of both buildings with errors within 20% in relative acceleration and 7% in roof displacement. Friction has been found to significantly affect the seismic response as it reduces the peak top displacement up to 31%.
Although there are several steel-to-timber joint types, there is still a lack of studies that more precisely characterize the components in the interaction between steel and timber in compression. ...Thus, this work aims to characterize the steel T-stub compressing the glued laminated timber (GLT) parallel to the grain component, focusing on formulating analytical expressions for design resistance, stiffness coefficient and deformation capacity. In order to validate the analytical models and increase the reliability of the component method, an experimental campaign was conducted through compression tests on 90 specimens composed of steel T-stubs with five different flange thicknesses under full and partial compression. It was identified that although GLT has lower compressive strength and lower stiffness than steel, the main failure mode in specimens studied was T-stub flange yielding. The proposed formulations were consistent with the experimental results and it can be used to predict the structural behavior of this component. The application of the component analytical variable elastic approach to a semi-rigid connection showed an increase in the accuracy for predicting its moment resistance.
•The main failure mode observed was the T-stub flange yielding, due to small stiffness of the flange and to the concentration of stresses in the central region of the timber.•The component is characterized by proposing equations for resistance, stiffness coefficient, and deformation capacity. The precision of these parameters has been improved compared to experimental results and to equations proposed by other authors for joints with similar geometry.•Experimental evaluation of the steel T-stub compressing timber parallel to the grain component carried out with five different T-stub thicknesses and timber subjected to full and partial compression.
Recently historic timber structures in Turkey are unfortunately not given the value they deserve. Although timber structures are unique symbols of our cultural heritage, they are forgotten for ...natural and human reasons. On the other hand, when traditional timber structures standing today to repairs and / or reinforcements and restorations are examined, it is seen that timber elements according to the knowledge and skill of construction foreman are constructed with different types of structural systems. This matter reveals that choosing the right timber structural system is very important. This study the effects of their behaviour of traditional timber structural systems of different types widely used in the construction of timber structures in Turkey were comparatively examined. With this purpose, teen different structural system models with the Sta-stell program of the timber-framed (with Çatkı) Safran mansion which is widely used in Turkey were created and the findings were compared with each other by carried out structural analyses. The findings obtained reveal that buttresses are important in meeting, distributing and transferring the loads acting on the structural system, especially earthquake loads, to the foundation and the displacement distributions in the storey levels of the buttressed building models are less. In addition, the findings obtained show that buttresses that increase the lateral rigidity of timber structures increase the performance of the structure in question and reduce the internal forces of the structural elements. Turkey's widely used timber structural systems (in accordance with the Safran mansion architecture, which received the best restored mansion award) were modelled and analysed. The results presented are aimed to design recommendations and better understanding of the behaviour of different timber structural systems in today’s architectural practice.
Recently historic timber structures in Turkey are unfortunately not given the value they deserve. Although timber structures are unique symbols of our cultural heritage, they are forgotten for natural and human reasons. On the other hand, when traditional timber structures standing today to repairs and / or reinforcements and restorations are examined, it is seen that timber elements according to the knowledge and skill of construction foreman are constructed with different types of structural systems. This matter reveals that choosing the right timber structural system is very important. This study the effects of their behaviour of traditional timber structural systems of different types widely used in the construction of timber structures in Turkey were comparatively examined. With this purpose, teen different structural system models with the Sta-stell program of the timber-framed (with Çatkı) Safran mansion which is widely used in Turkey were created and the findings were compared with each other by carried out structural analyses. The findings obtained reveal that buttresses are important in meeting, distributing and transferring the loads acting on the structural system, especially earthquake loads, to the foundation and the displacement distributions in the storey levels of the buttressed building models are less. In addition, the findings obtained show that buttresses that increase the lateral rigidity of timber structures increase the performance of the structure in question and reduce the internal forces of the structural elements. Turkey's widely used timber structural systems (in accordance with the Safran mansion architecture, which received the best restored mansion award) were modelled and analysed. The results presented are aimed to design recommendations and better understanding of the behaviour of different timber structural systems in today’s architectural practice.
This paper aims to present an experimental study investigating the seismic behaviour of spatial and planar hoop-head mortise and tenon (MT) timber joints in traditional Guangfu Ancestral Halls. The ...unique design of the external hoop head provides additional restraints for the tenon and mortise in these joints, endowing them with enhanced pull-out resistance and increased structural integrity compared to other types of MT connections commonly used in traditional timber-framed structures. The research commenced with material testing to determine the mechanical properties of Merbau wood used in this timber frame construction. Reversed cyclic loading tests were then performed on two planar and two spatial hoop-head MT timber joints. The experimental results demonstrated the favourable seismic performance of the hoop-head MT joints. All specimens failed within the MT joint area, exhibiting different failure modes based on varying connection configurations and tenon sizes. Furthermore, the spatial MT joints showed lower stiffness and bearing capacities compared to the planar MT joints of equivalent size. Their hysteresis curves, envelope curves, and cyclic stiffness degradation curves displayed greater asymmetry. These discrepancies can be attributed to the reduction in tenon sections necessary to accommodate the overlapping beams within the spatial joint core area.
•Cyclic loading experimental tests were conducted on two planar and two spatial hoop-head mortise and tenon (MT) timber joints.•The seismic performance of the spatial and planar hood-head mortise and tenon timber joints was investigated.•The spatial MT joints showed lower capacities and more asymmetry in mechanical behaviour than planar MT ones with same size.
In the last two decades, mass timber structures have gained popularity in mid-rise or tall building applications worldwide. For timber buildings in seismic regions, it is critical to improve building ...seismic resilience. Conventional timber structures rely on connections for energy dissipation and system ductility. However, this dependence also carries the risk of damage, potentially resulting in structures that are irreparable in severe earthquakes. In this regard, as one of the low-damage seismic design technologies, self-centering (SC) techniques have been introduced to mass timber structures in 2005. The relevant research and applications have led to significant technological progress in the field. This paper provides an overview of recent research progress since 2019, encompassing experimental studies, analytical and numerical simulations, key design aspects, and practical applications of SC mass timber structures. It highlights recent technological advancements and identifies future research directions to address knowledge gaps identified in this review.
•This paper reviews developments in SC mass timber structures, including experiments, simulations, design aspects, and applications.•In addition to the PT technique, experimental study on other SC technologies used in mass timber structures are also included.•Research that contributes to the design of SC mass timber structures is covered.
This study is aimed at investigating those parameters related to timber flooring that can affect the acceptability of vibration behaviour of a timber floor in a residential building in view of the ...criteria stated in Eurocode EC5. The timber floor investigated is made of OSB/3 floorboards and timber joists. The parameters that are investigated in this study are thickness of flooring, floor joist span, joist spacing and connection of floorboards to the joists. In this context, two cases are considered. First: the flooring is nailed or screwed to the joists and no composite action or interaction is obtained between joists and floorboards. Second: the flooring is glued sufficiently to the joists and full interaction is obtained. The result suggests that glued floorboards perform much better with respect to natural frequency, static deflection and peak floor velocity than nailed or screwed floorboards. In almost all cases of glued floorboards, the result complies fully with the Eurocode 5 design vibration requirements. However, as floor lengths increase, the static deflection will increase beyond the allowable limit, especially for relatively thin floor panels and relatively widely spread joists. For both cases, increasing floorboards thickness and decreasing the joist span by adding more beams can yield even better results to satisfy the requirement of vibration comfort.
