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Computed tomography (CT) is an excellent tool to solve certain engineering problems connected to material science (such as sulfate swelling, internal degradation due to freezing, and alkali silicate swelling) and to understand specific processes (frost peeling, acid action). Albeit borne and mostly used in the medical domain, CT is increasingly used in the examination of the internal structure of building materials, where degradation processes occur to the detriment of their mechanical performance and durability. This paper presents five engineering problems concerning concrete freezing and thawing, concrete at high temperatures, timber charring, spalling in asbestos‐cement pipes, and deterioration in prestressed concrete pipes due to the corrosion of metallic inserts. In each case, the degradation processes are monitored via CT, something that may be crucial in the renovation and preservation of historical structures. [ABSTRACT FROM AUTHOR]

Translation abstract A new town hall for HainburgThe new town hall building in Hainburg unites the administrations of Hainstadt and Klein‐Krotzenburg town halls under one roof. The building does not look like a classic administrative building in its design language. The generous recessing of the ground floor over a corner and the building‐high atrium behind it make the structure look more like a light, inviting pavilion with a welcoming atmosphere. The building was constructed in timber, which is not only part of the structure but also a design element in the interior. Only the ground floor and the stiffening core were built in solid construction. The town hall‘s energy concept uses sustainable materials and fulfils the most modern requirements. A photovoltaic system on the roof completely covers the power supply for the entire building and the operation of the air/water heat pumps for the underfloor heating. The vertically structured façade was clad in bronzed metal sheets. The daylight falling on it enhances the impression of a building of high architectural quality. This article describes the project‘s planning constraints and the attempt to consistently realise the architectural idea in the supporting structure. It also focuses on analysing the calculated CO2 equivalent using the slab above the first floor as an example. [ABSTRACT FROM AUTHOR]

An efficient design method should provide practitioners with a means for sizing timber buildings to meet specific performance levels against estimated earthquake intensities. Displacement and energy design considerations in force-based design (FBD) procedures are not as precise as intended in complex systems, such as mid- to high-rise timber buildings. The main aim of this study is to tailor the direct displacement-based design (D-DBD) classical framework to platform-type cross-laminated timber (CLT) shear wall structural systems and validate their performance for low-rise to high-rise timber mixed-use buildings. A comparison with results obtained via the FBD analyses is also provided. To this end, timber buildings with heights of 4, 8 and 12 stories are designed via the D-DBD and FBD methods. The seismic performance of platform-type CLT wall buildings is assessed in terms of the repair cost, repair time and casualty rate using FEMA P-58 methodology. The seismic response of CLT shear walls shows that the FBD method may lead to an expensive overdesign, especially in high-rise platform-type CLT walls. Conversely, the D-DBD method develops structural systems which can sustain a comparable level of damage from low- to high-rise platform-type CLT walls. Although the seismic loss assessment of buildings shows slightly better performance for the FBD method than the D-DBD method, it is worth noting that the D-DBD method does not lead to an unsafe building. Consequently, the D-DBD method sounds like a proper alternative approach for designing the CLT shear walls to achieve target performance levels without requiring a premium upfront cost. [ABSTRACT FROM AUTHOR]

This study deals with the design of modern environmentally friendly and non-toxic flame retardants based on expandable graphite 25 K + 180 (EG) modified by cellulose ethers (Lovose TS 20, Tylose MH 300, Klucel H) and nanocellulose (CNC) that are biocompatible with wood and, therefore, are a prerequisite for an effective surfactant for connecting EG to wood. The effectiveness of the formulations and surfactants was verified using a radiant heat source test. The cohesion of the coating to the wood surface and the cohesion of the expanded graphite layer were also assessed. The fire efficiency of the surfactants varied greatly. Still, in combination with EG, they were all able to provide sufficient protection—the total relative mass loss was, in all cases, in the range of 7.38–7.83% (for untreated wood it was 88.67 ± 1.33%), and the maximum relative burning rate decreased tenfold compared to untreated wood, i.e., to 0.04–0.05%·s−1. Good results were achieved using Klucel H + EG and CNC + EG formulations. Compared to Klucel H, CNC provides significantly better cohesion of the expanded layer, but its high price increases the cost of the fireproof coating. [ABSTRACT FROM AUTHOR]

This article presents a detailed analysis of a numerical model for studying the failure of masonry structures that have been retrofitted with timber solutions. The model accurately reproduces the failure mechanisms of masonry and evaluates the effectiveness of timber-based retrofitting. The study validates the model through comparisons with experimental and numerical results and assesses its efficacy through nonlinear static analysis. The article also discusses the use of a timber frame system as a retrofitting strategy for masonry walls, highlighting its significant enhancement of the wall's load-bearing capacity against lateral forces. However, the post-peak behavior of the retrofitted cases reveals potential weaknesses in the timber frame system, which can lead to sudden drops in resistance. The article concludes by emphasizing the importance of preventing simultaneous failure of multiple bracing elements in the retrofitting system and the need for further research to improve its design and mitigate brittle behavior. [Extracted from the article]

The substantial volume of timber recovered from the aftermath of the eruption of Vesuvius in 79 AD offers a valuable resource for gaining insights into the timber trade during Roman times. Silver fir emerges as the dominant species in construction within the Vesuvian region. While this species once thrived more abundantly along the Apennines, it now exists only in small, isolated groups, raising the possibility that the Romans contributed to its scarcity. Nevertheless, the origins of the substantial quantity of silver fir wood discovered in Pompeii, Herculaneum, and the surrounding areas remain unclear. This study examines 35 wood samples obtained during the excavation of the Moregine site, an ancient commercial port located a mere 600 m to the south of Pompeii's walls. Dendrochronological analysis successfully dated 19 out of the 35 samples. Despite silver fir not being the ideal species for dendroprovenancing analysis, certain observations can be made regarding its likely foreign origin. The correlation with chronologies of different species of Central European origin, the presence of species such as spruce/larch among the structural material and the existence of different groups among the material analysed are strong indications that demonstrate the foreign origin of at least some of the timber. Dendrochronological data further support that the wood trade played a strategically significant role in the economy of ancient Rome. [ABSTRACT FROM AUTHOR]

Aside from aesthetic appearance, recycling, ease of disassembly, decent resistance against corrosion, and no intense moisture condensing and thermal bridge, compared with steel fasteners, wooden fasteners also have the compatibility of stiffness with the assembled timber members, which reduces the risk of splitting of the assembled timber members. Due to higher mechanical properties, densified wood (DW) has become an alternative to natural wood as wooden fasteners. At present, investigations have mostly focused on timber-to-timber joints with single DW dowel, while multidowel timber joints are common in practice. In this study, the timber-to-timber joints with laterally loaded single and multiple DW dowels were tested under the loading parallel to the grain in order to explore the effects of the number of DW dowels, moisture content, and joint geometry, i.e., spacings and edge and end distances for DW dowels on mechanical behaviors of timber joints. The tests on the timber-to-timber joints with steel dowels were also performed to compare with those with DW dowels. The load-carrying capacities provided by individual DW dowels showed no reductions with the increases in the number of DW dowels and moisture content and the decrease in joint geometry. The experimental results suggest that the load-carrying capacity of multiple DW dowel joints can be estimated by using the load-carrying capacity of single DW dowel joints multiplied by the number of DW dowels in the range of joint geometries and numbers of DW dowels adopted in this study. The smaller spacings and edge and end distances for DW dowels adopted in this study than the minimum joint geometry requirements in Eurocode 5 are feasible. [ABSTRACT FROM AUTHOR]

A dual structural system for low-to-medium-rise buildings is examined, comprising light-timber frames (LTF) coupled with a cross-laminated timber (CLT) wall. To enhance the energy-dissipating capacity of LTF featuring pinching behavior, friction sheathing-to-frame connections have been proposed in place of conventional nail connectors. The resulting friction LTFs (FLTF) exhibit sustainably rich hysteresis loops that significantly enhance energy dissipation capacity. Nevertheless, the friction-dissipating mechanism leads to nonuniform story drift distributions and residual drifts in multistory FLTF buildings. To address this issue, a CLT wall with self-centering hold-down connections is coupled to the multistory FLTF building for imposing uniform story drifts and for reducing residual drifts. A direct displacement-based design (DDBD) approach is employed to design the dual CLT-FLTF system and ensure (i.e., impose) uniform seismic demand across the height of the building. Nonlinear-time-history analysis (NTHA) and incremental dynamic analysis (IDA) show that the DDBD approach can lead to safe designs and effectively control the displacements of the proposed dual system. [ABSTRACT FROM AUTHOR]

Typical household recyclable bin in Australia contains around 60% of waste cardboard. Given the possibilities of developing a construction material, this study conducted a life cycle assessment (LCA) comparing the development of cardboard trusses with © timber trusses, encompassing production to construction. The results show that cardboard trusses offer significant environmental benefits, including a 73% reduction in climate change category, an 83% decrease in ozone-depleting potential, and almost complete avoidance of agricultural land occupation compared to timber trusses, showcasing their sustainability. In both material manufacturing and material transportation, cardboard trusses prioritize climate change mitigation, accounting for over half of the environmental impact. Timber trusses, in contrast, heavily impact land occupation and exhibit climate change dominance. A benefit analysis highlights advantages of cardboard trusses, particularly in reducing land occupation, sustainability, circular economy, and particulate matter formation. The life cycle cost analysis demonstrates an impressive 83% cost reduction for cardboard trusses compared to timber trusses, despite higher labor costs during manufacturing. [ABSTRACT FROM AUTHOR]

The exposed-dowel half-through tenon (EHT) joint is a common and important connection configuration in southwest China. However, deformation and looseness in the EHT joint constitute the primary causes of failure in the joint connection performance. In this study, a mechanical model of the joints under bending was established and analyzed. The geometric, physical, and equilibrium equations were constructed, the bending moment-rotation relationship was obtained, and the bending moment-rotation envelope curve and the flexural capacity were calculated. A low cycle reciprocating experiment of the EHT joint was conducted to measure the moment-rotation hysteretic curve and envelope curve of the joints. A comparison of the envelope curves calculated using the model and test curves was conducted, and the results showed that the calculation curve was in good agreement with the test curve. The ultimate bending capacity errors of the joint in the forward loading stage and reverse loading stages were 11.2 and 5.8%, respectively. A parametric analysis of the joint using the established mechanical model showed that increasing the diameter of the wooden pillar and the width of the tenon greatly improved the flexural capacity of the joints while increasing the height of the small tenon and reducing that of the joints during the reverse loading stage. These research results provided a reference for the new construction and restoration of the Drum Towers in southwest China. [ABSTRACT FROM AUTHOR]

As the main parameter, embedment strength is used to assess the load-carrying capacity of timber joints with dowel-type fasteners and foundation modulus is used to assess their stiffness. The embedment properties, i.e. embedment strength and foundation modulus, are system properties, which depend not only upon the material properties but also upon the load-to-grain angle and surface conditions of fasteners. The formulae for the embedment strengths of dowels and bolts in the design standards of timber structures are almost exclusively derived from the embedment tests on smooth dowels, with the surface conditions different from those of alternative fully threaded bolts in timber structures. Moreover, there are hardly any formulae for determining the foundation modulus. In this study, the embedment tests at different angles to the grain were carried out using the fully threaded bolts with different diameters in oversized holes as they would be used in practice. The load-to-grain angle had statistically significant effects on these embedment properties. The empirical formulae for the embedment strength and foundation modulus were derived. The embedment tests on fully threaded bolts and smooth dowels in tight-fitting holes were also performed to explore the effects of bolt hole sizes and surface conditions. [ABSTRACT FROM AUTHOR]

In the field of civil engineering, the utilization of bio-based composites is a viable solution for promoting environmentally friendly practices. A novel bio-based inorganic-bonded bamboo composite (InorgBam) prepared with roller-pressing impregnation, cold pressing, and molding technology was first introduced, and 72 double-shear specimens were tested to investigate the load-carrying performance of InorgBam single-bolted connections. The failure characteristics of the InorgBam single-bolted connections were evaluated using the European yield model (EYM). By incorporating the existing bilinear and Attiogbe models, the load-displacement relationship of the InorgBam single-bolted connections was foretasted with precision. The effect of bolt diameter and component thickness on load-bearing capacity was compared, and relevant design suggestions were proposed. Prediction equations of load-bearing capacity for timber connections in existing standards were briefly reviewed and compared with the test results to illustrate their applicability for InorgBam connections. Comparison results indicated that the equations for timbers exhibited an adequate safety redundancy for the InorgBam. Finally, a simplified equation was proposed based on nonlinear fitting that aims to provide a convenient approach to design activities for InorgBam bolted connections and promote the structural application of InorgBam material. [ABSTRACT FROM AUTHOR]

Sorting of sawn timber batches is crucial for efficient kiln-drying. This study aimed to verify the hypothesis of different drying attributes of 25 mm thick sapwood and mixed Scots pine boards sawn from a group of butt, second, and top logs and assess the effects of kiln-drying. Three options dry-bulb temperature were taken into account. The drying results were evaluated based on the final moisture content distribution, changes in the cross-sectional dimensions of the sawn timber, drying time, and unit heat consumption. Correlations between sawn timber features, drying temperature, and drying results were analyzed using non-parametric statistical tests. The study proved the dependence of the initial moisture content and wood density variation of Scots pine sawn timber on the log type and the position on the round timber cross-section. The variation of drying attributes of the sapwood and mixed 25 mm Scots boards is insignificant in the final moisture content distribution and cross-sectional dimensions. However, green sorting may have only a beneficial effect on drying time and heat consumption. [ABSTRACT FROM AUTHOR]

Cracks exist in the majority of components of ancient Chinese timber structures and have led to serious mechanical property degradation problems, threatening the safety of the whole structures and making the cracks' detection for wooden components a necessity. With the rapid development of intelligent protection technology of cultural buildings, it is important to establish a scientific identification and quantification method for cracks in wooden components to replace traditional manual detection techniques. Deep learning is precisely such an advanced technology. In this study, images of cracked wooden components were first collected from the Yingxian wooden pagoda and the crack characteristics were analyzed. A dataset for crack segmentation was established using a total of 501 images of cracked wooden components, including a training dataset of 450 images and a validation dataset of 51 images. Based on the mathematical principles of deep learning and the fully convolutional neural networks (FCNN), a deep fully convolutional neural network (d‐FCNN) model was constructed based on encoding and decoding methodology. Four model indicators, pixel accuracy (PA), average pixel accuracy (mPA), mean intersection over union (mIoU), and F1‐score were analyzed to train the model and determine the optimal model parameters, including learning rate, batch size, and epoch. It concluded that the optimal initial learning rate takes the value of 10−4, batch size of 6, and epoch of 100, achieving the average accuracy of 78.8%. Further, based on the pixel's accumulation principle, a quantitative calculation method for crack length and maximum width was proposed. Two cracked wooden columns were prepared, and crack image identification and quantification experiments were conducted to verify the correctness of the constructed d‐FCNN model and the proposed crack quantification method. The results show that the model is suitable for crack intelligence detection, identification, and quantification of cracked wooden components. [ABSTRACT FROM AUTHOR]

The masonry veneer wall system relies on metal wall ties to connect the outer masonry leaf to the internal frame, ensuring structural stability. In Australia, a masonry veneer wall typically consists of a timber frame that has galvanised wall ties fixed to the side of the timber studs, with a nail or screw, spanned across an air cavity to the external leaf of masonry. This study explores the impact of corrosion on the integrity of these wall ties, emphasising their susceptibility to failure during extreme events. Existing literature highlights tension failure in a veneer wall is the result of nail pull-out from the timber. In the current research, accelerated corrosion of an R2 (Z600) wall tie reveals that tensile strength reduction is due to decreasing tie cross section from corrosion, leading to wall tie fracture rather than nail pull-out. Understanding these failure mechanisms is crucial for building assessment and monitoring strategies for masonry structures, especially in regions prone to extreme wind or seismic activity in combination with corrosion susceptibility, such as coastal environments. [ABSTRACT FROM AUTHOR]

Composite steel‐timber beams – initial ideas for structural design Since the introduction of the Green Deal and the EU Taxonomy Regulation, pressure in construction market has increased to design load‐bearing structures in addition with a view to greater sustainability. Composite beams in steel‐timber construction can contribute to this. However, reliable calculation rules for steel‐timber composite beams do not yet exist. Working Group 6 of TC11 in the European Convention for Constructional Steelwork (ECCS) deals with hybrid steel‐timber structures and this article presents initial ideas for calculation approaches for steel‐timber composite beams. The problems are tackled that, in contrast to concrete, the material timber has a significant tensile strength and the different types of shear connectors between steel and timber can also show a variety of load‐slip curves. Finally, a first comparison between the presented calculation method and a large‐scale test is presented. [ABSTRACT FROM AUTHOR]

Asymmetric timber trade between least-developed countries with large forest resources but backward processing industries and emerging economies has led to an uneven distribution of value in international timber commodity chains. Selling their raw timber with no domestic value added contributes little to socio-economic development and is associated with high rates of deforestation. The Lao PDR has served as a raw timber frontier for advanced timber industries in neighboring countries, leading to forest loss and related environmental problems. In response, since 2015, the Lao government has adopted drastic policy measures to end forest degradation and upgrade its timber industry (e.g., log export ban). Using teak as an example, our study provides empirical ex-post evidence on the effectiveness of state-imposed timber industry upgrading policies. The study relies on expert interviews with key policy actors at national and local levels, as well as an enterprise survey and cluster analysis conducted in Xayyabouly province. These drastic policies had far-reaching implications for the structure of the timber industry and the configuration of the timber value chain and rural development. [ABSTRACT FROM AUTHOR]

Strong seismic events frequently strike Chile. The last three significant events that caused considerable damage and losses are the 2010 ( M w 8.8, Maule), 2014 ( M w 8.2, Iquique), and 2015 ( M w 8.3, Illapel) earthquakes. Therefore, reliable fragility curves are necessary to evaluate the threat of earthquakes to the built environment. This study aims to develop empirical fragility curves of Chilean houses using damage from the 2014 and 2015 earthquakes. The data from 9085 and 7431 damaged houses from the 2014 and 2015 earthquakes, respectively, was obtained by the government. The fragility curves were estimated for reinforced concrete, reinforced masonry, timber, and adobe houses. Additionally, the fragility curves were constructed using three different Peak Ground Acceleration (PGA) maps to quantify the variation of the fragility parameters based on the selected PGA map and to identify which PGA map generates the highest correlation with observed damage. Additionally, fragility curves obtained in this study are compared with curves from other studies. The median θ values of the fragility curves obtained in this study are larger than those from other reported studies. [ABSTRACT FROM AUTHOR]

The control authorities of timber trade lack quick and easy methods to verify the legality of the traded product. This includes the clear identification of the timber species. In this study, a simple genetic method, the macroarray technique, was modified and optimised for this purpose. The internal transcribed spacer (ITS) was used as barcode region. Specific probes were designed and tested using this barcode of trade-relevant, CITES protected wood species and their look-alikes. The results reveal that 61 of these probes are suitable for identification purposes. Hence, 32 of the 50 investigated species can be clearly identified using the developed macroarray. Additional 15 species are represented by probes in groups of two to three species, which enables a delimitation of the species present. For four species, no identification was possible applying the probes created. The findings indicate the potential of time and cost savings compared to currently established methods in species control in the timber trade. [ABSTRACT FROM AUTHOR]

One of the most damaging pathogens of pinewood is the pinewood nematode, Bursaphelenchus xylophilus, which could cause an adverse effect on the ecosystems of forests and the commerce of timber. Therefore, it is crucial to realize rapid and accurate B. xylophilus detection. In this work, an accelerated strand exchange amplification method (ASEA) was established to detect B. xylophilus for the first time. By integrating with fast nucleic acid extraction, the whole detection procedure could be finished within 30 min, dramatically shortened the detection time. The ASEA method exhibited high specificity towards B. xylophilus and the detection limit for B. xylophilus plasmid DNA was as low as 1.0 × 100 copies/μL. Furthermore, the ASEA approach also exhibited accurate detection for B. xylophilus when applied to actual pinewood samples, meeting the demand of B. xylophilus detection in realistic scenario. We believe the ASEA method has significant potential for B. xylophilus detection, and it will be helpful for controlling forest pest and quarantine regulations. [ABSTRACT FROM AUTHOR]

Structural mass timber has been used more often in buildings over the last 5 years, given its potential to be a sustainable alternative. However, concerns still exist around the fire safety of mass timber structures, and current mass timber building designers must consider a variety of fire protection strategies, including but not limited to noncombustible protection and design for sacrificial char thickness. This research focuses on better understanding how prescriptive code fire protection strategies affect the sustainability goals that have partially driven mass timber use. This paper studies how decisions during early design can reduce embodied carbon (EC), the initial energy use of a structure's construction. Five structural floor system types were modeled parametrically for various levels of fire protection. System types included timber–concrete composites, cross-laminated timber (CLT)–steel hybrids, and all-timber systems. The resulting EC data analysis reveals that all-timber systems perform the best for EC when the fully protected option is used at shorter spans, when the combined approach option is used at midrange spans, and when the fully exposed timber option is used at longer spans. Across all studied systems, the shallowest possible depth occurred for the 10-ft (3.05-m) spanning CLT–steel hybrid systems at 11.5 in. (292 mm) deep for the fully protected system, and the lowest possible EC was 10.5 lb CO2 eq/ft2 (51.3 kg CO2 eq/m2) for the fully protected 10-ft (3.05 m) all-timber system. [ABSTRACT FROM AUTHOR]

The building industry requires the development of a ductile lateral force resisting system made of mass timber to help mass timber to continue to grow in popularity as the primary structural building material. The OpenSees framework was used to develop a numerical model of a single-story timber frame with a timber buckling-restrained brace, which was validated by the results of a previously completed series of quasistatic cyclic timber buckling-restrained brace (TBRB) component and subassembly tests. The experimental validation included a model developed for the hysteretic behavior of the TBRB and the rotational capacity of beam–column joints made with mass ply lam (MPL) panels, two slotted-in steel plates, and a number of steel dowels. The single-story model TBRB braced frame was then expanded to a numerical model of an eight-story mass timber buckling-restrained braced frame. The TBRB frame was analyzed with static pushover, quasistatic cyclic loads, and earthquake simulations. During the simulation of eleven design-level earthquake ground motions, the building experienced a peak interstory drift at of 2.54% at the first-floor level and a peak floor acceleration of 1.7g at the roof. The numerical model developed in this research of a timber buckling-restrained braced frame with TBRBs is novel and could be used to design timber buckling-restrained braced frames as a ductile lateral force resisting solution for mass timber buildings in seismic regions. [ABSTRACT FROM AUTHOR]

Reinforced concrete structures constructed in coastal areas in Indonesia often suffer damage before reaching their intended service life, with steel reinforcement corrosion being a major contributing factor. This study aims to investigate the use of concrete structures produced with simple methods and inadequate supervision in coastal regions. Reinforced concrete structures near the coast are susceptible to carbonation due to marine environmental factors, leading to reinforcement corrosion. The study was conducted on the Dande Dandere Market building, Tanakeke Island, Takalar Regency, South Sulawesi. The research method employed quantitative techniques, including surveys and structural testing. Visual inspections were conducted to identify the types of damage present in the building and estimate their causes. Structural testing involved both destructive and non-destructive tests. Concrete compressive strength testing was also conducted to assess the concrete sample's compressive strength, along with carbonation testing to determine the acidity level of concrete due to the intrusion of salt compounds or carbonation formed within the concrete mass. The research findings indicate structural degradation in the market's construction, occurring more rapidly than the intended lifespan of the building. Signs of structural degradation in the reinforced concrete construction include spalling of concrete cover on beams, supporting columns, and cantilever slabs, as well as degraded reinforcement, with an average reduction in steel weight of 62.70% over six years, and an average weight loss of 0.103 grams per day. Therefore, efforts are needed to optimize the structural quality of the building through comprehensive repairs, starting from the foundation. However, for cost-efficient alternatives, it is recommended to use timber structural materials for new market construction. The use of timber in coastal buildings, which are vulnerable to marine influences, is more feasible as the presence of saltwater can inhibit wood decay caused by microorganisms. [ABSTRACT FROM AUTHOR]

Intending to safeguard architectural heritage, the assessment of the health of timber structures is crucial, though challenging, due to the organic nature of wood and to the uncertainties of its preservation state. To this end, useful support is provided by the ICOMOS guidelines, which provide conservation strategies based on thorough diagnosis and safety evaluations. In this context, the study summarized in this paper focuses on the medieval Tower of Montorio, which suffered considerable damage due to the strong earthquake that occurred in those area in September 2003. Its subsequent process of rehabilitation and restoration involved a widespread experimental campaign and the substitution of some timber beams. This circumstance has offered a rare opportunity to study these ancient elements in detail, although they are limited in number. Six beams made of oak and removed from an intermediate floor of the tower were evaluated through a comprehensive approach that included both non-destructive tests (NDT) and destructive tests (DT). Particularly, they were subjected to visual inspections, ultrasonic, sclerometric, and resistographic methods, and destructive four-point bending tests. Overall, the study presented here provides a useful qualitative comparison between them. Results highlighted that relying only on NDT might lead to an overestimation of mechanical properties and that combining NDT with DT is crucial for a more accurate assessment. Therefore, the need to deepen the research on correlations between NDT and DT to obtain reliable values of mechanical properties while respecting the conservation aim was confirmed. [ABSTRACT FROM AUTHOR]

High-rise timber structures signify a rising trend, thanks to their significant environmental and economic advantages that occur over their complete lifespan. Enhancing spatial effectiveness in these structures is a critical design consideration for project feasibility. Currently, there has been no comprehensive study on the space efficiency of such towers. This article analyzed 79 cases all over the world to deepen the knowledge of design features shaping spatial efficiency. The critical findings are as follows: (1) the most common architectural preferences include residential function, a centrally located service core, and prismatic arrangements; (2) the preferred structural material is composite, while a shear walled frame system is the favored structural system; (3) the average spatial efficiency and percentage of core area to GFA were recorded at 84% and 10%, ranging from the lowest values of 70% and 4% to the highest values of 95% and 21%, respectively; and (4) no significant differences were detected in the effect of core design approaches on spatial effectiveness if appropriately planned, with similar inferences drawn concerning form and the structural material used. This article will assist in developing design directions for different interested parties, including architectural designers taking part in the advancement of high-rise timber towers. [ABSTRACT FROM AUTHOR]

A fundamental requirement for analysing timber structures under fire is to consider the degradation of material properties with temperature. Therefore, the objective of this study is to propose a model that accounts for the variation of the thermo-physical properties, the development of char, and its evolution with temperature. This model integrates a sequential coupling of heat transfer analysis with structural response. The degradation of the material properties is accounted for through the regulatory approach recommended in Eurocode 5. The stress analysis employs an elasto-plastic model with nonlinear isotropic hardening. Implementation of the model is achieved within the Abaqus suite of finite element software using external subroutines. The model's predictions align well with experimental data, accurately reproducing both thermal and structural responses. Specifically, the model accurately predicts temperature profiles, displacements, and the depth of the charred layer, which initiates above 300 °C. Additionally, for rectangular sections, it was observed that exposure of all faces to fire results in a non-rectangular residual section. Furthermore, employing the temperature-dependent thermal property curves suggested by EC5 yields satisfactory results when predicting the fire resistance of softwood timber structures. [ABSTRACT FROM AUTHOR]

This paper explores the creation, development, and dissemination of prefabricated concrete rural houses in Jiangsu Province in East China from 1961 to the 1980s, an example of the technological transition provoked by the depletion of forest and timber in China. Through archival research, fieldwork and interviews, the paper examines the two waves of design and dissemination of prefabricated concrete rural houses between 1961 and 1965 and their subsequent 'vernacularisation' in the 1970s and the 1980s. This research provides a twofold insight into the current scholarly debates surrounding built heritage and global climate change. On one hand, it addresses a historical context of concrete overuse in contemporary China, a matter of critical importance in relation to carbon emissions and global climate change. On the other hand, it offers a counter-argument to today's call for reintroducing timber structures in many places, as evidenced by the case of East China, where the widespread use of materials like concrete was primarily a consequence of the ecological crisis following decades of deforestation and timber resource depletion. In addition, the 'vernacularisation' of concrete structures manifested by this case still provides lessons for today's efforts to popularise more eco-friendly construction materials and technologies, especially in rural areas, and the prefabricated concrete houses possess potential heritage values as trackers of ecological changes. [ABSTRACT FROM AUTHOR]

This study addresses the enhancement of material efficiency and reduction in brittleness in timber-to-concrete adhesive connections for beam-type timber and timber-concrete composite panels. The research explores the potential benefits of adding longitudinal timber ribs to cross-laminated timber (CLT) beam-type panels. Three groups of flexure-tested specimens were analysed as follows: (1) timber panels (1400 mm × 400 mm) with two 100 mm thick CLT panels and two 60 mm thick CLT panels reinforced with 150 × 80 mm timber ribs; (2) eight specimens (600 mm × 100 mm × 150 mm) with CLT members (600 mm × 100 mm × 100 mm) connected to a 50 mm concrete layer using granite chips and Sikadur-31 (AB) epoxy adhesive; (3) six CLT panels (1400 mm × 400 mm × 50 mm) bonded to a 50 mm concrete layer, with two panels containing polypropylene microfibres and two panels incorporating polyethene dowels for mechanical connection. Specimens were subjected to three-point bending tests and analysed using the transformed section method, γ-method, and finite element method with ANSYS 2023R2 software. Results indicated a 53% increase in load-carrying capacity for ribbed CLT panels with no additional material consumption, a 24.8–41.1% increase for CLT panels strengthened with a concrete layer, and improved ductility and prevention of disintegration in timber-concrete composites with polypropylene microfibres. [ABSTRACT FROM AUTHOR]

The main objective of this work is to characterize the stress–strain relationship of cross-laminated timber (CLT) wall panels when loaded in compression and how different confinement mechanisms provide compression reinforcement for the CLT panels. CLT crushing tests were performed to define the behavior of CLT under compression up to the failure point, defined here as the strain at which the gross stress falls by 20% from the peak value. Testing included monotonic uniform compression experiments of five-ply CLT with specimens that were 0.457 m wide by 1.52 m long. The motion of the specimens perpendicular to loading direction was restrained at midlength to prevent buckling. Twelve specimens were tested, including six bare CLT specimens and six reinforced specimens of CLT—three with self-tapping screws while the other three with self-tapping screws and an additional U-shape steel plate at the bottom of the specimens. Various damage points were observed during the tests, including (1) point at the onset of damage (through visual observation and instrumental observation) (2) point of initiation of strength degradation, (3) point at which buckling occurs, (4) point at which 25.4 mm delamination was observed, and (5) failure point. Three axial compression stress–strain models were adopted, calibrated, and compared. Results indicate that a stress–strain model combining linear and cubic functions for the elastic and softening responses, respectively, captures well the CLT inelastic behavior under compression. [ABSTRACT FROM AUTHOR]

Digital Image Correlation (DIC) is a technique that permits full analysis of the strain field distribution upon the surface of solids. The nonlinear bonding interaction between poplar timber and CFRP (Carbon Fiber Reinforced Polymers) reinforcement under mixed mode I&II is analyzed. The test setup inserts an eccentric axial load and a corresponding bending moment. The experiments show strain distributions composed of two lateral transfer zones in which bonding mode II predominates and, a central zone of constant strain in which bonding mode I is dominant. The maximum load capacity increases with the bond length until the effective bond length. [ABSTRACT FROM AUTHOR]

Cross-laminated timber (CLT) buildings are constructed by connecting CLT panels with dowel-type fasteners and mechanical anchors, which govern the lateral behavior of these structures. Although these connections are mostly distributed along the perimeter of the CLT panels, creating highly redundant structures, previous research on the lateral behavior of CLT structures has mainly focused on the behavior of the connections placed at the base of the CLT shear walls, such as hold downs and angle brackets, while limited attention has been paid to the connections between perpendicular walls and their effect on the lateral response of CLT shear walls. This paper presents a comprehensive experimental study aimed at investigating the effects of the interaction between perpendicular walls on the lateral response of CLT shear walls. CLT shear walls with three different aspect ratios were analyzed by means of monotonic and cyclic tests, both in single wall configuration and connected to perpendicular walls. The experimental findings demonstrate that the structural interaction due to the perpendicular walls significantly affects the lateral response of a CLT shear wall, resulting in increased lateral stiffness, lateral capacity, and deformation capacity. In addition, the study presents two analytical models for the prediction of the lateral stiffness and the lateral capacity of CLT shear walls connected to perpendicular walls. The analytical models were validated based on the experimental results, showing reasonable agreement. [ABSTRACT FROM AUTHOR]

This study proposed a novel type of self-centering (SC) timber beam–column connection utilizing shape memory alloy (SMA) bars and investigated its cyclic behavior through experimental and numerical studies. In this SC connection, anchor bars consisting of SMA bars, steel bars, and couplers were utilized to connect the beam and column and achieve SC and energy dissipation capabilities. The configuration of the SC timber beam–column connection and material properties of the SMA bars were first introduced. The cyclic behavior of the SC timber beam–column connection was systematically investigated through experimental and numerical studies. A series of cyclic loading tests were conducted on the SC timber beam–column connection to evaluate its stiffness, SC, and energy dissipation capabilities, and the effect of multiearthquake loading. A detailed finite element model of the timber connection was also built and validated using the experimental results. Results indicated that the timber connection could exhibit a desirable flag-shaped hysteretic behavior, indicating favorable SC and moderate energy dissipation capabilities. The connection remained functional without any repair work after experiencing two consecutive cyclic loads up to 4% drift ratios, demonstrating its potential to withstand multiple seismic events. [ABSTRACT FROM AUTHOR]