The application of mass timber elements in different structures has gained publicity over the last few years,pri-marily due to climate change adaptation policies and net zero carbon targets.Timber is a renewable const...The application of mass timber elements in different structures has gained publicity over the last few years,pri-marily due to climate change adaptation policies and net zero carbon targets.Timber is a renewable construction material that can outperform other building materials regarding environmental impact.However,when used in seismically active regions,its application has been limited due to the uncertainties on their seismic behaviour in respect with different design standards and limited ductility in conventional connections.Conventional timber connections typically suffer from stiffness and strength degradation under cyclic loads.Their repairability is also low due to permanent damage in the fasteners and the associated crushing in the wood fibres.The use of friction connections can be an efficient way to mitigate these issues.They offer many advantages as they are economical and yet provide a high level of reliable and continuous energy dissipation.In recent years,a new generation of friction connections has been developed that can provide self-centring behaviour(i.e.,the ability of the structure to return to its original position at the end of an earthquake).However,how these connections perform compared to a mass timber system with conventional timber connections is still unknown.Several studies in the literature have suggested that these connections can enhance the performance of mass timber structures.However,the seismic performance of such systems specifically in terms of base shear,response drifts and response accelerations-has not been thoroughly investigated.This paper examines various design aspects of conventional friction connections and self-centring friction connections,providing insights into their differences concerning key seismic performance indicators.It compares the seismic performance of mass timber buildings equipped with both solutions,highlighting their advantages and limitations and drawing conclusions based on the results.The key findings are that friction connections can provides a superior seismic performance for timber structures.However,that may need to be combined with a parallel system avoid residual displacements.展开更多
Platform-style construction is a widely recognized and well-established approach among engineers and developers for multi-story mass timber buildings.This construction method offers many advantages,such as rapid assem...Platform-style construction is a widely recognized and well-established approach among engineers and developers for multi-story mass timber buildings.This construction method offers many advantages,such as rapid assembly,an excellent strength-to-weight ratio,and appealing aesthetic features.In a platform-type construction,each story is constructed by placing the floor panels on top of the load-bearing wall,creating a platform for the level above.Although this method offers numerous advantages,recent research findings have revealed that cross-laminated(CLT)platform buildings with conventional connections,such as wall-to-floor hold-down brackets and shear connectors with nails and screws,are prone to experience a high degree of damage under design-level earthquakes.Consequently,conventional connections in platform-type construction are vulnerable to more damage under aftershocks and do not meet the damage avoidance requirements of seismic design.This paper introduces an innovative floor-to-wall connection for a platform-type low-rise mass timber building that mitigates the limitations of conventional connections.The effectiveness of the proposed connection has been investigated,and the seismic performance of the system,which incorporates the proposed connection,has been outlined in this paper.A numerical model with an innovative inter-story isolation system is developed in ETABS,and the seismic performance of the isolated structure was evaluated using Response Spectrum Analysis(RSA)and Nonlinear Time History Analysis(NLTHA).This study revealed that inter-story isolation systems significantly reduced the seismic demands on the mass timber components,demonstrating the system’s ability to dissipate seismic energy.Additionally,the system displayed effective energy dissipation while exhibiting self-centering behaviour.展开更多
The tropical timber trade faces significant sustainability challenges,including deforestation,illegal logging,and inadequate traceability.Inaccurate species identification further complicates these issues,leading to u...The tropical timber trade faces significant sustainability challenges,including deforestation,illegal logging,and inadequate traceability.Inaccurate species identification further complicates these issues,leading to unreliable trade statistics and enforcement challenges.The Lacey Act Amendment(LAA)of 2008 mandated declaring scientific names for timber shipments entering the United States.Therefore,this study assessed the implementation of the LAA using data obtained through a Freedom of Information Act request to the United States Department of Agriculture-Animal and Plant Health Inspection Service for 4 tropical timber species including Keruing,Meranti,Acajou d’Afrique,and Mahogany from Indonesia,Malaysia,Brazil,Philippines,Cameroon,Ghana,Congo,Cote d’Ivoire,and Bolivia,with high rates of illegal logging.This study showed that the United States imported 49 species of Keruing species group,126 species of Meranti species group,6 species of Acajou d’Afrique species group,and 2 species of Mahogany species group during 2017-2023.Despite mandatory declarations,approximately 14.60%of timber import records lacked species-specific names.Conservation assessments identified 37 species of Keruing species group and 68 species of Meranti species group listed as threatened by the International Union for Conservation of Nature(IUCN)but absent from the Convention on International Trade in Endangered Species of Wild Fauna and Flora(CITES).Moreover,the principal component analysis(PCA)indicated that the first principal component was primarily driven by import value and import volume,reflecting the overall trade prominence,while the second principal component captured temporal pattern through import year.Further,this study developed a Trade-Adjusted Conservation Priority Index(TACPI)that integrated conservation status with trade prominence to prioritize species at risk.Species with high TACPI scores,such as Dipterocarpus coriaceus and Shorea balangeran,were identified as urgently needing regulatory focus.To strengthen sustainable trade and conservation,it is recommended to enforce the LAA more strictly,expand timber identification technologies,and mandate key supplier countries,who are the CITES’signatories,to list high-risk species in the CITES appendices.展开更多
在国家全面推进实现乡村振兴和“双碳”目标的背景下,提升乡村建设品质与风貌特色成为核心任务。文章研究聚焦乡村参数化木结构装配式建筑设计展开研究,对国家政策和地方政策进行考察,并通过中国学术期刊全文数据库和Web of Science搜...在国家全面推进实现乡村振兴和“双碳”目标的背景下,提升乡村建设品质与风貌特色成为核心任务。文章研究聚焦乡村参数化木结构装配式建筑设计展开研究,对国家政策和地方政策进行考察,并通过中国学术期刊全文数据库和Web of Science搜集整理了国内外相关论文文献,借助CiteSpace文献工具对乡村装配式木结构参数化设计研究数据进行可视化分析。研究针对2000—2025年乡村建设研究趋势,提出在乡村振兴背景下利用Grasshopper和Revit等BIM技术探索乡村参数化建设新途径的设计策略,为乡村参数化木结构装配式建设发展提供参考依据。展开更多
针对我国4家胶合木企业的两类产品进行了从摇篮到大门阶段的碳足迹评价,并评估了其生命周期不同阶段的碳储量。研究表明:运输阶段是胶合木碳足迹的主要来源,占比超72%。原料获取阶段的碳排放主要来源于锯材,生产阶段的碳排放与电力消耗...针对我国4家胶合木企业的两类产品进行了从摇篮到大门阶段的碳足迹评价,并评估了其生命周期不同阶段的碳储量。研究表明:运输阶段是胶合木碳足迹的主要来源,占比超72%。原料获取阶段的碳排放主要来源于锯材,生产阶段的碳排放与电力消耗及不同省份电力排放因子密切相关。正交胶合木因高能耗工序及大面积施胶,其电能及胶黏剂导致的碳排放高于层板胶合木。在同类型胶合木中,产品及层板结构、树种和运输路径亦影响其碳足迹。胶合木是天然储碳建材,其碳储量为736.6~883.9 kg CO_(2)e/m^(3),在使用阶段可长期稳定封存。胶合木的回收利用可延长碳储期,但不合理的废弃处理方式可能导致部分碳储释放,从而造成更高的碳排放。研究结果可为胶合木行业提供数据参考和理论借鉴。展开更多
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 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展开更多
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 monodirecti...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.展开更多
文摘The application of mass timber elements in different structures has gained publicity over the last few years,pri-marily due to climate change adaptation policies and net zero carbon targets.Timber is a renewable construction material that can outperform other building materials regarding environmental impact.However,when used in seismically active regions,its application has been limited due to the uncertainties on their seismic behaviour in respect with different design standards and limited ductility in conventional connections.Conventional timber connections typically suffer from stiffness and strength degradation under cyclic loads.Their repairability is also low due to permanent damage in the fasteners and the associated crushing in the wood fibres.The use of friction connections can be an efficient way to mitigate these issues.They offer many advantages as they are economical and yet provide a high level of reliable and continuous energy dissipation.In recent years,a new generation of friction connections has been developed that can provide self-centring behaviour(i.e.,the ability of the structure to return to its original position at the end of an earthquake).However,how these connections perform compared to a mass timber system with conventional timber connections is still unknown.Several studies in the literature have suggested that these connections can enhance the performance of mass timber structures.However,the seismic performance of such systems specifically in terms of base shear,response drifts and response accelerations-has not been thoroughly investigated.This paper examines various design aspects of conventional friction connections and self-centring friction connections,providing insights into their differences concerning key seismic performance indicators.It compares the seismic performance of mass timber buildings equipped with both solutions,highlighting their advantages and limitations and drawing conclusions based on the results.The key findings are that friction connections can provides a superior seismic performance for timber structures.However,that may need to be combined with a parallel system avoid residual displacements.
基金gratitude to WIDE Trust New Zealand for providing the opportunity and funding for this research,as well as QuakeCoRE,a New Zealand Tertiary Education Commission-funded Centre,for partially funding this research.This is QuakeCoRE,publication number 1013.
文摘Platform-style construction is a widely recognized and well-established approach among engineers and developers for multi-story mass timber buildings.This construction method offers many advantages,such as rapid assembly,an excellent strength-to-weight ratio,and appealing aesthetic features.In a platform-type construction,each story is constructed by placing the floor panels on top of the load-bearing wall,creating a platform for the level above.Although this method offers numerous advantages,recent research findings have revealed that cross-laminated(CLT)platform buildings with conventional connections,such as wall-to-floor hold-down brackets and shear connectors with nails and screws,are prone to experience a high degree of damage under design-level earthquakes.Consequently,conventional connections in platform-type construction are vulnerable to more damage under aftershocks and do not meet the damage avoidance requirements of seismic design.This paper introduces an innovative floor-to-wall connection for a platform-type low-rise mass timber building that mitigates the limitations of conventional connections.The effectiveness of the proposed connection has been investigated,and the seismic performance of the system,which incorporates the proposed connection,has been outlined in this paper.A numerical model with an innovative inter-story isolation system is developed in ETABS,and the seismic performance of the isolated structure was evaluated using Response Spectrum Analysis(RSA)and Nonlinear Time History Analysis(NLTHA).This study revealed that inter-story isolation systems significantly reduced the seismic demands on the mass timber components,demonstrating the system’s ability to dissipate seismic energy.Additionally,the system displayed effective energy dissipation while exhibiting self-centering behaviour.
基金United States Endowment for Forestry and Communities in coordination with the Northern Forest Center for partial funding(No.91093)of the project.
文摘The tropical timber trade faces significant sustainability challenges,including deforestation,illegal logging,and inadequate traceability.Inaccurate species identification further complicates these issues,leading to unreliable trade statistics and enforcement challenges.The Lacey Act Amendment(LAA)of 2008 mandated declaring scientific names for timber shipments entering the United States.Therefore,this study assessed the implementation of the LAA using data obtained through a Freedom of Information Act request to the United States Department of Agriculture-Animal and Plant Health Inspection Service for 4 tropical timber species including Keruing,Meranti,Acajou d’Afrique,and Mahogany from Indonesia,Malaysia,Brazil,Philippines,Cameroon,Ghana,Congo,Cote d’Ivoire,and Bolivia,with high rates of illegal logging.This study showed that the United States imported 49 species of Keruing species group,126 species of Meranti species group,6 species of Acajou d’Afrique species group,and 2 species of Mahogany species group during 2017-2023.Despite mandatory declarations,approximately 14.60%of timber import records lacked species-specific names.Conservation assessments identified 37 species of Keruing species group and 68 species of Meranti species group listed as threatened by the International Union for Conservation of Nature(IUCN)but absent from the Convention on International Trade in Endangered Species of Wild Fauna and Flora(CITES).Moreover,the principal component analysis(PCA)indicated that the first principal component was primarily driven by import value and import volume,reflecting the overall trade prominence,while the second principal component captured temporal pattern through import year.Further,this study developed a Trade-Adjusted Conservation Priority Index(TACPI)that integrated conservation status with trade prominence to prioritize species at risk.Species with high TACPI scores,such as Dipterocarpus coriaceus and Shorea balangeran,were identified as urgently needing regulatory focus.To strengthen sustainable trade and conservation,it is recommended to enforce the LAA more strictly,expand timber identification technologies,and mandate key supplier countries,who are the CITES’signatories,to list high-risk species in the CITES appendices.
文摘在国家全面推进实现乡村振兴和“双碳”目标的背景下,提升乡村建设品质与风貌特色成为核心任务。文章研究聚焦乡村参数化木结构装配式建筑设计展开研究,对国家政策和地方政策进行考察,并通过中国学术期刊全文数据库和Web of Science搜集整理了国内外相关论文文献,借助CiteSpace文献工具对乡村装配式木结构参数化设计研究数据进行可视化分析。研究针对2000—2025年乡村建设研究趋势,提出在乡村振兴背景下利用Grasshopper和Revit等BIM技术探索乡村参数化建设新途径的设计策略,为乡村参数化木结构装配式建设发展提供参考依据。
文摘针对我国4家胶合木企业的两类产品进行了从摇篮到大门阶段的碳足迹评价,并评估了其生命周期不同阶段的碳储量。研究表明:运输阶段是胶合木碳足迹的主要来源,占比超72%。原料获取阶段的碳排放主要来源于锯材,生产阶段的碳排放与电力消耗及不同省份电力排放因子密切相关。正交胶合木因高能耗工序及大面积施胶,其电能及胶黏剂导致的碳排放高于层板胶合木。在同类型胶合木中,产品及层板结构、树种和运输路径亦影响其碳足迹。胶合木是天然储碳建材,其碳储量为736.6~883.9 kg CO_(2)e/m^(3),在使用阶段可长期稳定封存。胶合木的回收利用可延长碳储期,但不合理的废弃处理方式可能导致部分碳储释放,从而造成更高的碳排放。研究结果可为胶合木行业提供数据参考和理论借鉴。
基金the Key Technologies R&D Program of Harbin (0111211102).
文摘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
基金The National Natural Science Foundation of China(No.51138002,51578127)
文摘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.
