Export Competitiveness and Sustainable Development of the Ukrainian Timber Industry

This paper conducts a comprehensive analysis of the export dynamics within the Ukrainian timber industry, emphasizing its pivotal role in the national economy. The study begins by outlining the research objectives, context, and innovative methodologies, setting the stage for a deep dive into the theoretical underpinnings of sustainable and competitive trade. It explores Ukraine’s rich forest biodiversity across varied vegetation zones and its geopolitical significance. Detailed evaluations of forest resource management, policy frameworks, and institutional support form the core of the analysis. Challenges such as imbalanced export structures and legal inconsistencies are critically examined. The research employs trade gravity models and competitive indicators like the Revealed Comparative Advantage (RCA) and Market Share (MS) to assess factors influencing exports and to forecast potential growth areas. The findings inform strategic recommendations aimed at enhancing export capacity through market diversification, brand development, and legal stability. The conclusion highlights the need for strategic interventions to harness Ukraine’s timber resources sustainably, balancing economic gains with environmental stewardship.

Experimental Investigation on the Strength and Ductility Performance of Steel-Timber-Steel Joints with Screw and Steel-Tube Fasteners

This article presents experimental results of steel-timber-steel(STS)joints loaded parallel to grain.Eight groups of specimens were designed,and tensile tests were performed.The fastener types and fastener numbers were considered to evaluate the tensile strengths and ductility performances of the STS joints.The screws with 6 mm diameter and the innovative steel-tubes with 18 mm diameter were adopted as connecting fasteners.The experimental results were discussed in terms of yielding and ultimate strengths,slip stiffness,and ductility factors.The ductility classification and failure mechanisms of each group of specimens were analyzed.It was demonstrated that the STS joint with large diameter steel-tubes showed acceptable ductility,which was close to the ductility of the STS joint with small diameter screws,thanks to the hollow structure of the steel-tube.The theoretical strengths of various failure modes for the joints with small diameter screws or large diameter steel-tubes were calculated and compared with the experimental results.The ductile performance of the STS joint was discussed by comparing the theoretical strengths of various failure modes.The effective number of the STS joint with multifasteners was also analyzed by considering the failure mechanisms in aspects of tensile strength and slip stiffness.

An Experimental Study of Composite Columns Filled with Eucalyptus nitens Timber under Axial Compression

Eucalyptus nitens(E.nitens)has been much used for producing paper but also shows promise for structural applications.In this study,static compressive tests were undertaken to examine its suitability to be used in an innovative composite column.The composite column was comprised of a rectangular steel tube with E.nitens timber infill.The nonlinear compressive behaviour of the composite column filled with E.nitens wood for both dry and wet conditions was examined.The same tests on rectangular steel tubes and bare dry and wet E.nitens samples were also undertaken as a comparison.For samples with different conditions,the ultimate capacity was evaluated and the effect of each condition on the compressive behaviour of the composite column was clarified.The steel tubes showed greater ductile behaviour,and more ductility was found in the wet samples.The steel tubes with E.nitens timber infill samples exhibited a greater linear elastic range connected with higher maximum loads,while the bare timber samples could support only lower maximum loads.The results from this research were promising for the use of rectangular steel tubes with E.nitens timber infill in structural applications.

Three-dimensional inversion of knot defects recognition in timber cutting

The comprehensive utilization of wood is the main goal of log cutting,but knot defects increase the diffi-culty of rationally optimizing cutting.Due to the lack of real shape data of knot defects in logs,it is diffi cult for detection methods to establish a correlation between signal and defect morphology.An image-processing method is proposed for knot inversion based on distance regularized level set segmentation(DRLSE)and spatial vertex clustering,and with the inversion of the defects existing relative board position in the log,an inversion model of the knot defect is established.First,the defect edges of the top and bottom images of the boards are extracted by DRLSE and ellipse fi tting,and the major axes of the ellipses made coplanar by angle correction;second,the coordinate points of the top and bottom ellipse edges are extracted to form a spatial straight line;third,to solve the intersection dispersion of spatial straight lines and the major axis plane,K-medoids clustering is used to locate the vertex.Finally,with the vertex and the large ellipse,a 3D cone model is constructed which can be used to invert the shape of knots in the board.The experiment was conducted on ten defective larch boards,and the experimental results showed that this method can accurately invert the shapes of defects in solid wood boards with the advantages of low cost and easy operation.

In Situ Generation of Copper Nanoparticles in Heat-Treated Copper-Containing Masson’s Pine as a Preservative Process for Sawn Timber

Heat-treated wood has good dimensional stability,durability,and color,but its susceptibility to fungal growth affects its commercial value.In this study,lumber harvested from mature Masson’s pine(Pinus massoniana Lamb.)was vacuum impregnated with a basic copper salt solution(copper hydroxide,diethanolamine,and polyethylene glycol 200)prior to heat-treatment at 220℃ for 3 h.Antifungal properties,surface chemistry,crystal structure and sugar contents were tested,compared with heat treatment alone.The results showed that the samples treated by heating without copper salt treatment showed poor suppression of fungal growth,the copperimpregnated heat-treated wood suppressed(100%)the growth of Botryodiplodia theobromae Pat.,Aspergillus niger V.Tiegh.,Penicillium citrinum Thom,and Trichoderma viride Pers.The combined results of X-ray photoelectron spectroscopy,X-ray diffraction and sugars analysis suggested that fungal inhibition by the heat-treated copper-bearing Masson’s pine was mainly due to the reduction of the metal salt by PEG200 at high temperature to generate copper nanoparticles.In addition,the reduced sugar content of the treated timber,and hence the nutrient substrate for spoilage microbes,reduced in the presence of the metal salts at high-temperature.This study has demonstrated an effective method of increasing low-grade wood’s utility and commercial value.

Verification of Depth Adjustment Factor in Eurocode 5 for Tropical Hardwood Timbers

The depth adjustment factor for bending strength stated in Eurocode 5(EC5)is only applicable to timbers having a characteristic density below 700 kg/m^(3).However,most Malaysian timbers are hardwood,some with a characteristic density reaching above 700 kg/m^(3).Therefore,the objective of this study was to examine whether the depth adjustment factor stipulated in EC5 is valid for Malaysian hardwood timbers.Six timber species were selected for this study,namely Kapur(Dryobalanops C.F.Gaertn.),Kempas(Koompassia Maingay ex Benth.),Keruing(Dipterocarpus C.F.Gaertn.),Light red meranti(Shorea Roxb.ex C.F.Gaertn.),Geronggang(Cratoxylum Blume)and Balau(Shorea Roxb.ex C.F.Gaertn.).The determination of bending strength and characteristic density was conducted according to BS EN 408:2010 and BS EN 384:2016,respectively.A graph for mean bending strength vs.(150/h)was plotted for each timber species.The power function was selected to analyze the relationship between the two variables.The power of the regression equations varied depending on the characteristic density of the timber species.For species with a characteristic density below 700 kg/m^(3),such as Kapur,Keruing,and Light red meranti,the power was between 0.16 to 0.17.In contrast,for species having a characteristic density above 700 kg/m^(3),namely Kempas and Balau,the power was higher at 0.23 and 0.24,respectively.Geronggang was an exception to this pattern.These values are close to the depth adjustment factor given in EC5,which is 0.2.Based on the results,it can be suggested that the adjustment factor of 0.2 is also applicable to Malaysian hardwood timbers with a characteristic density above 700 kg/m^(3).

Determination of the Properties of Some Selected Timber Species for Structural Application

One of the alternative sustainable and green construction materials to concrete is timber. Timber is of numerous varieties, and this acts as a barrier to the extent of its usage, especially in structural application. Despite many researches on wood’s mechanical and physical properties, only a few are geared toward the structural application of wood. The present work investigated the mechanical properties of five timber species;Gmelina arborea, Tectona grandis (Teak), Terminalia superba (Afara), Ayin (Anogeissus leiocarpus), and Acacia (Robinia pseudoacacia), to determine their suitability for constructing long-span roof trusses. These are available in the South Western part of Nigeria. Their mechanical properties;bending strength, compressive strength, shear strength, tensile strength, Modulus of Elasticity (MOE), Modulus of Rupture (MOR), and density, were determined in the laboratory. The results obtained showed that all the timber types, except Terminalia superba (Afara), have higher values of mechanical properties than the values that are obtainable for classes of strength D30 to class D70 in the British Code of Practice. It means these species are of higher quality than the stipulated strength classes in the British code. The results also show that the order of relevance of the species for structural design (or work) is Acacia (Robinia pseudoacacia), Ayin (Anogeissus leiocarpus), Gmelina Arborea, and Tectona grandis (Teak). Terminalia superba (Afara) is not recommended for structural works.

Novel Proposal of Bio-based Sewing Timber Joint:Learning from Diatoms

The twenty-first century is one of the most complex in the history of humanity,mainly due to the ecological crisis it is going through.The construction sector generates about 40%of CO2 emissions into the environment;the foregoing should motivate this sector to seek new alternatives to develop new building practices.Taking these current needs into account,this document classifies and presents a multidisciplinary solution that integrates biology,engineering and architecture to develop a new and innovative lightweight timber structure;it divides with a main structure made of timber and an innovative joint system made of bio-polymers connecting all the panels.Through the study of diatoms,it was able to analyze the bio-morphology of the structure,joints and in particular the geometry since they were the inspiration for the design of this structure that presents an innovative and novel design of structural optimization.Through parametric design and digital fabrication,it was able to create a complex geometry that obtains excellent structural behavior.This research discusses and explores how materials,geometry led to the optimization of a structure and how new structures can arise,thanks to biology new solutions can be obtained that are completely sustainable,being a clear example of how to combat the effects of the climate change and in a precise way it highlights the advantages of the bio-design in the architectural design.

Application of single neuron adaptive PID controller during the process of timber drying

The paper presents a method of using single neuron adaptive PID control for adjusting system or servo system to implement timber drying process control, which combines the thought of parameter adaptive PID control and the character of neural network on exactly describing nonlinear and uncertainty dynamic process organically. The method implements functions of adaptive and self-learning by adjusting weighting parameters. Adaptive neural network can make some output trail given hoping value to decouple in static state. The simulation result indicates the validity, veracity and robustness of the method used in the timber drying process

Mechanical properties of monodirectional Gutou mortise-tenon joints of the traditional timber buildings in the Yangtze River region

The mechanical properties of the monodirectional Gutou mortise-tenon joints of the ancient Chinese traditional timber buildings in the Yangtze River region were studied using the experimental method. Three monodirectional Gutou mortise-tenon joints were designed according to the actual configurations. The failure modes,the hysteretic curves,the skeleton curves, the rotation rigidities, and the energy dissipation capacity of this type of mortise-tenon joints under the low cyclic reversed loading were obtained. The results show that the hysteretic curves of the monodirectional Gutou mortise-tenon joints appear to be Z shape and have obvious pinch effects. During the process of the test,these mortisetenon joints pass orderly through the elastic stage,the yield stage and the failure stage. The energy dissipation capacity of these mortise-tenon joints generally decreases with the increase in the rotation angle. The equivalent viscous damping coefficients of the monodirectional Gutou mortise-tenon joints are between 0. 161 and 0. 193. The results can provide the theoretical base for the computing analysis and repair design of Chinese traditional timber buildings in the Yangtze River region.

Structural Carpentry in Qing Dynasty-A Framework for the Hierarchically Modularized Chinese Timber Structural Design

This article, by using mathematical expressions, offers a scientific framework for understanding how the grading system of Qing′s structural carpentry determines the design and construction in the grand style timber architecture.The Qing′s grand style timber structure, which is ready for prefabrication and assembly, is extremely hierarchical oriented and significantly standardized. The general procedure in designing a grand style timber structure is to start with the grade that defines the basic module (dou kou); next comes with the number of bracket set (cuan), the number of longitudinal bays and the number of purlins which affect its plan and cross section; thirdly choose a roof type that determines its longitudinal section and the facade as well. A series of formulae are conducted to help depict the layout, cross sectional roof curvature and special longitudinal treatments in 4 sloped and 9 spined roofs respectively.

Shifting Private Timberland Ownership in South Carolina: Implications for Management Intensity

Beginning in the late 1970’s forest industry timberland gained the eye of financial investors. Diamond International and Crown Zellerbach were early firms that were purchased for the “break-up value” of their timberland. Timberland was perceived as undervalued by investors and made forest industry firms attractive takeover targets. This started a process where forest industry divested of its timberland. Some firms formed separate entities for its timberland base. Acquisitions and mergers became popular in the industry. Some forest industry companies converted to real estate investment trusts, for tax and defensive reasons. Large institutional investors became interested in timberland as means to diversify their portfolios and increase financial performance. Timber management investment organizations developed to manage and procure timberland for these institutional investors. Today little of the forest industry timberland remains with vertically-integrated forest products companies. South Carolina’s forest industry timberland decreased by about 800,000 ha since 1993 (or nearly 90%). This has implications for the state’s timber supply. Forest industry timberlands were some of the most productive and intensively managed forests in the state. We address how forest management might change on this timberland and how long-term timber supply might be impacted in the state.

Numerical Investigation of Connection Performance of Timber-Concrete Composite Slabs with Inclined Self-Tapping Screws under High Temperature

The timber-concrete composite(TCC)slabs have become a preferred choice of floor systems in modern multi story timber buildings.This TCC slab consisted of timber and a concrete slab which were commonly connected together with inclined self-tapping screws(STSs).To more accurately predict the fire performance of TCC slabs,the mechanical behavior of TCC connections under high temperature was investigated by numerical simulation in this study.The interface slip of TCC connections was simulated by a proposed Finite Element(FE)model at room temperature,and different diameter and penetration length screws were considered.The effectiveness of this FE model was validated by comparing with the existing experimental results.Furthermore,the sequentially coupling thermal stress analyses of this model were conducted,and the relationship between the reduction coefficient of connection performance and the effective penetration length of screws was summarized.This study gave the fit-ting expressions for the reduction coefficient of slip modulus and joint strength.Finally,the numerical investiga-tions of the fire performance of TCC slabs considering the char fall-off of Cross Laminated Timber(CLT)were performed to verify the effectiveness of the proposed reduction law.Comparing the fire-resistance time with experimental results showed deviation of the proposed model was−14.02%.

A Review on Strengthening of Timber Beams Using Fiber Reinforced Polymers

Fiber reinforced polymer(FRP)has been used in the construction industry because of its advantages such as high strength,light weight,corrosion resistance,low density and high elasticity.This paper presents a review of bonding techniques adopted to strengthen timber beams using FRP to achieve larger spans.Different methods of bonding between FRP and timber beams have been summarized with a focus on the influencing factors and their effects as well as relevant bond-slip models proposed for fundamental understanding.Experimental investigations to evaluate the flexural performance of timber beams strengthened by FRP bars,sheets and wraps have also been critically reviewed to identify key influencing parameters.Limited research available on the shear performance of FRP reinforced timber beams have been analyzed to determine the influencing factors of the shear performance in timber-FRP beams.The paper finally presents an overall summary of the current-state-of-the-art and proposes some future research directions in the field.

Preservation Strategies of Timber-framed Arch Bridges as Cultural Landscape Heritage

Theoretical study on and safeguarding of cultural landscape heritage has been put on the agenda of heritage protection in Zhejiang and Fujian provinces.The safeguarding of timber-framed arch bridge heritage in the past 5 decades could be classified into 3 stages,and heritage protection in all 3 stages was closely related to original meaning of "landscape",which proved that timber-framed arch bridge heritage had profound inside information,and the safeguarding of timber-framed arch bridge from the perspective of cultural landscape heritage was worth further study.Safeguarding of timber-framed arch bridge cultural landscape heritage focused on integrated conservation,but not protection of individual bridges.Integrated conservation of world heritage is to maintain and restore the integrated environment landscape of the heritage,thus protection of timber-framed arch bridge heritage is not only to explore its architectural craftsmanship,but also to lay a foundation for the dynamic succession of such craftsmanship as intangible cultural heritage.Value of the existing timber-framed arch bridges as historic building heritage was discussed,and it was proposed that ultimate objectives of the safeguarding could be realized step by step from 3 layers.

Effects of timber infill walls on the seismic behavior of traditional Chinese timber frames

This study investigates the enhanced effect of timber infill walls on the seismic behavior of traditional Chinese timber frames.Two 1/2 scaled traditional Chinese timber infill walls(TIWs),two 1/2 scaled timber frames with timber infill walls(TFTIWs)and one 1/2 scaled timber frame(TF)were fabricated and tested under low-cyclic reversed loading.The failure modes,strength,stiffness,and energy consumption capacity of the TIWs and the TFTIWs were obtained,and the effects of the TIWs on the seismic performance of the TFTIWs were investigated.The results showed that the TIWs can increase the stiffness and ultimate bearing capacity of the TF,up to 60%and 80%,respectively.The strength degradation coefficient of the TFTIWs was slightly higher than that of the TF when the inter-story drift ratio exceeded 0.02 rad,and the TIWs helped to mitigate the strength degradation of the TFTIWs.It was also found that the TFTIWs had a higher cumulative energy dissipation when compared with the TF(up to a 60%increase),indicating the TIWs had reasonably good energy dissipation capacity.When the TIWs generated a solid contribution to the carrying capacity and energy dissipation of the TF,the lateral drift thresholds were 1/100 and 1/43 of the column height,respectively.Furthermore,the TIWs and TFTIWs presented a good ductility,and the TIW could effectively reduce the pull-out amount of the tenon from the mortise of the TF;however,the TIWs had little influence on the stiffness degradation level or improvement of the ductility of the TF.

Comparative Study on Various Strength Parameters of Structural Elements Made from Cross-Laminated Timber

Cross laminated timber(CLT)is an innovative and environment friendly engineered timber product with superior structural performance.CLT offers strong resistance against both in-plane and out-of-plane loading.Hence,it is widely used as floors,roofs or wall elements.Considerable experimental research on CLT under various loading conditions has been done in the recent past.This article presents a comprehensive review of various design methods to determine basic mechanical properties such as tension,compression and rolling shear strength of CLT with primary focus on Norway spruce.All relevant experimental data available from existing literature were collated and consequently been used to evaluate the performance of various methods to design CLT structures.The comparison revealed that different methods show considerable variance in predicting the capacity of CLT panels due to the variation in timber species,which affects the corresponding mechanical properties of the lamella.In addition to species,rolling shear properties can also vary considerably depending on the type of experimental technique used for testing.A predictive model has also been proposed to correlate rolling shear strength obtained from shear analogy method to that obtained using planar shear.

Bending,Compression and Bonding Performance of Cross-Laminated Timber(CLT)Made from Malaysian Fast-Growing Timbers

This study investigated the bending,compression as well as the bonding performance of CLT panels made from fast-growing timber species,i.e.,Laran(Neolamarckia cadamba)and Batai(Paraserianthes falcataria).The variables studied were timber species(Laran and Batai),layers of lamination(3-layer and 5-layer),loading direction in bending(in-plane and out-of-plane),loading direction in compression(x-,y-,and z-axis)and different treatment conditions for bonding performance test.The desired outputs of this study were bending and compression properties(strength and stiffness)as well as bonding performance(block shear strength,wood failure percentage and delamination value).The bending and compression test were conducted according to EN16351:2015 and EN408:2012,respectively.On the other hand,the bonding performance test was determined by block shear and delamination test based on EN16351:2015 and EN14374:2004,respectively.Prior to block shear test,the samples were subjected to three different treatment conditions.The results showed that CLT made from 3-layer Laran timber,loaded at out-of-plane direction exhibited the highest bending properties.Contrarily,CLT made from 5-layered Batai timber,loaded at in-plane direction showed the lowest bending properties.Laran samples for compression loaded at x-axis exhibited the best compressive properties.Generally,Laran CLT showed greater bonding performance determined by shear test compared to Batai CLT for both 3-and 5-layer panels.On the contrary,delamination results showed that Batai CLT demonstrated better bonding performance compared to Laran CLT.In terms of bonding performance measured by wood failure percentage(WFP),most samples under various treatment conditions showed WFP≥80%except for samples under wet condition with WFP≤60%.

Tree-Shaped Timber Structural System

This paper lbcuses on the main characteristics of a tree-shaped timber structural system or simply tree-shaped. One of them is the complexity of its steel connections, responsible for the joint of bar elements, compounding a complex structural system, which requires the application of the CYPECAD software version 2007 to solve the calculations problems. Its efficiency was confirmed by a variety of laboratory tests carried out with the whole structure. The tree-shaped is a timber structure that can be used in a large number of destinations, including residences, malls, sheds, hangars, etc.. Originally, it was conceived based on the well-known masterpiece ＂Sagrada Familia＂, whose author was Architect Antoni Gaudi I Cornet （1852-1926） in Barcelona/Spain. It was designed at the end of 19th century and its construction is still not finished. Gaudi inverted the logical order of the gothic concepts, i.e., light weights below and heavy weights above. Based on this concept, he always had in mind the figure of a tree in nature. The tree-shaped follows the same idea, using timber pieces connected by steel plates. Theoretical and numerical analyses have shown its efficiency and lightness for use in timber structures.

Emerging Timber Bridge Program to Sao Paulo State： A Five-Year Report

The Emerging Timber Bridge Program to Sao Paulo state （ETBPSP） was started in 2001 with the main objective of research and development of new technologies for timber bridge construction. After five years of this program eleven demonstration timber bridges were constructed in the State of Sao Paulo, whereas eight composite timber/concrete bridges, one log timber girder bridge with transversal sawn deck, one transversal lumber prestressed timber bridge and one transversal cellular plywood box prestressed bridge. As a final objective is the divulgation of the constructive and structural systems in extension courses to municipal engineers and in a complete publication of timber bridges project plans with the different structural and constructional systems. This paper describes the goals of the MTBPSP, the accomplishments of the program in the first five years, the information sheet of the bridges and outlines some obstacles and opportunities.