The degradation mechanisms of wood scrimber under multifactorial environmental stress remain incompletely understood. In this study, poplar wood scrimber was subjected to cyclic accelerated aging tests. Comparative analyses were performed on samples before and after treatment to assess key surface characteristics, including color change, roughness, wettability, micromechanical properties, and chemical composition. The research reveals the underlying degradation mechanisms responsible for surface deterioration, the decline in micromechanical performance, and the breakdown of chemical constituents in wood scrimber under combined UV and hydrothermal exposure. The results indicated that the accelerated aging process led to a darkening and roughening of the wood scrimber surface, accompanied by the loosening of its fibrous structure. Concurrently, the chemical components exhibited differential degradation rates. As the PF resin itself degraded, its supportive role in the cell wall was diminished, resulting in reductions of 41.3 % in HIT and 40.8 % in Er of the cell wall after 240 h of aging.

Transverse compression damage frequently affects active wooden components of ancient architecture, such as beams and Dou-gong, compromising structural safety. Larch (Larix gmelinii var. principis-rupprechtii (Mayr) Pilger) wood, commonly used in ancient northern Chinese architecture, has limited studies on its transverse compression damage mechanisms. Traditional reinforcement methods are often ineffective. The present study integrated plastic equilibrium theory and static loading experiments to examine the transverse compression damage mechanism of larch wood under significant deformation. It also introduced an innovative method for parcel constraints to enhance the compression strength of wooden components in ancient architecture. Results showed the transverse compressive strength of larch wood ranges from 3 to 17 MPa, with maximum load-bearing capacity doubling after enhancement. End-wrapping confinement increased the load-bearing capacity by over 16%. Load-displacement curves under different compression conditions followed a three-stage pattern: elastic, plastic, and densification. Damage in larch wood began in the plastic stage. Under localized compression, samples exhibited a sudden drop in load-bearing capacity and secondary failure at 60-70% strain. This study offers valuable insights into the damage and residual load-bearing capacity of transversely compressed wooden components. The proposed compression enhancement strategy can reinforce damaged wooden components in ancient architecture, contributing to preserving cultural heritage.

Identification of structural wooden components is crucial for heritage architecture conservation as it elucidates the utilization patterns of forest resources and evolution of human civilization. This paper proposes a computer vision-based in situ identification method for wooden components of Chinese heritage architectures, using a dataset comprising 4050 images from 63 components of nine buildings. The optimal algorithm, RepLKNet, trained on coniferous xylarium specimens, achieves 96.67% identification accuracy, with 98.33%, 93.33%, and 90% precision at 50%, 70%, and 90% confidence thresholds, respectively. A minimum sample size of 25 species and 1500 images per genus ensures test accuracy >90%. Impact of structural deterioration (decay and cracks) on accuracy is also evaluated. Cracks significantly affect the wood recognition accuracy of historical components. Performance degrades significantly when cracks span >30% of the image. Latewood integrity is also critical to identification. The proposed method advances structural preservation strategies and preventive maintenance practices in heritage architecture.

Computer vision methods have been proven to be feasible in the field of digital forestry, including tree species identification on angiosperm xylem (hardwood) and can overcome the limitations of the traditional wood anatomical method in recognition accuracy. However, few studies exist on gymnosperm xylem (softwood). Owing to imperfections in the wood voucher specimen image database and the lack of a scientific approach to dataset division, its generalizability in practical applications is hindered. In this study, the largest Pinaceae Wood Cross-section Macroscopic (PWCM) Dataset was constructed, including 38,953 images of 22 common species within Pinaceae family distributed in China. Two approaches for dividing the datasets were compared, and four algorithms—ResNet50, SeResNet50, RepVGG-B2, and RepLKNet-31B—were established. Through algorithmic visualization and statistical analysis of misidentified images, an image selection principle applicable to the identification of Pinaceae wood was proposed. The results indicated that the computer vision method was suitable for verifying unknown images in known samples. The best algorithm, RepLKNet-31B, achieved 98.55% and 80.11% accuracy at the genus and species levels, respectively. The results of the algorithm visualization demonstrated that the main features affecting identification were changes in tracheid morphology during the transition between earlywood and latewood, as well as the growth rings and their adjacent tracheids. The error rate statistics of the growth ring widths showed that the best recognition results were achieved when the image contained one to three complete growth rings. Four image categories related to wood anatomical traits—the transition region between juvenile and mature woods, region around the tree pith, sapwood region near the bark, and region with sharp width variations between adjacent growth rings—significantly interfered with the accuracy of the algorithm recognition. This contributes a potential reference for softwood image acquisition standards. This study will provide technical support for agroforestry ecology safety supervision, forest biodiversity conservation, and forensic identification in related fields.

To investigate the potential of modified epoxy resin for repairing and strengthening historical wooden structures, this study utilized polyurethane and silicone-modified epoxy resin as the base, alongside a polyamine curing agent. The resin mixture was cured at ambient temperature, resulting in the creation of ten unique epoxy resin systems. Investigation into the chemical structure and alterations to the glass transition temperature were conducted. The study conducted tests and characterization of viscosity, curing rate, mechanical properties, stress failure mode, hygrothermal aging resistance, and bonding properties. The results reveal that the curing degree of the two modified epoxy resins is high after being cured at room temperature, and the chemical structure and curing rate show insignificant changes. The range of the glass transition temperature for the modified epoxy resin is between 61.31 °C and 70.51 °C. The incorporation of polyurethane and silicone molecular chains into the epoxy resin cross-linking curing system enhances the toughness of the epoxy resin. The modified resin achieves a maximum elongation at break that is 5.18 times greater than that of the unmodified resin, along with a maximum tensile strength and a compressive strength that are 7.94 and 1.74 times, respectively, higher than those in the Chinese technical specifications for the maintenance and reinforcement of ancient wooden structures. The increase in toughness changes the failure mode of the cured epoxy resin. The modified epoxy resin exhibits great bonding ability to aged wood, with a shear strength of up to 9.6 MPa along the grain. As a result, the modified epoxy resin meets the requirements for the reinforcement and repair of the timber members of ancient buildings.

This study aimed to investigate the effects of growth ring width, height from the tree base, and loading direction on the transverse compressive strength of Japanese larch wood, which is commonly used in wood structures in China. Plantation wood is often used to replace natural forest woods for reconstruction purposes, despite significant differences in properties (e.g., growth rings, density, strength) between them. The ends of transversely compressed wood members in such structures are prone to damage by breaking or crushing. A transverse compressive test was conducted following Chinese national standards, which revealed the following key findings. (1) There was a significant difference in the transverse compressive strength of wood with different growth ring widths (p < 0.05). The radial and slant compressive strength of wood increases with growth ring width, while the tangential compressive strength decreases as growth ring width increases. (2) The transverse compressive strength of wood decreases as the height from the tree base increases. The radial, tangential, and slant compressive strength at a lower height were 18.39%, 22.58%, and 18% higher than those at a greater height in the stem, respectively, with significant differences at the 0.05 level. (3) The load–displacement curve of Japanese larch wood under radial and slant compression follows a “three-segment” form. In contrast, the load–displacement curve of tangential compression is a continuous curve that drops sharply upon reaching its highest point. (4) There is a significant difference in the transverse compressive strength of Japanese larch wood in different loading directions when growth ring width and height from the tree base are constant (p < 0.05), which fall into order as tangential > radial > slant.

木材作为一种弹塑性材料,具有优异的强重比,被广泛应用于木结构建筑.由于其各向异性,木材不同方向的力学性能差异较大,在横纹受压荷载下存在屈服强度低、变形大等受力特征.木材横纹受压破坏现象在工程实际应用中普遍存在且难以避免,若不能及时妥善处理,会严重影响木结构的安全稳定性.由于各地保护政策以及修复技术的限制,对古建筑残损木构件进行增强与加固历来为学者们极力攻克的难题,因此对木材在横纹受压下的性能及加固增强进行研究具有重要意义.文中介绍中国、美国、日本等国家的木材横纹抗压测试标准,并梳理木材横纹受压影响因素的研究现状;概述木材横纹抗压强度的增强方法,尝试提出木材横纹受压及加固增强的发展趋势,以期为今后开展相关研究提供思路.

对应县木塔二层明层和五层明层内槽转角柱的普拍枋、华拱和泥道拱等横纹抗压构件进行勘测,测量其尺寸与含水率,使用相机拍照记录其破坏特征,后期利用ImageJ软件分析其裂隙率及破坏状况,探讨两明层横纹抗压构件的开裂程度与分布.结果表明:二层明层内槽转角柱上的普拍枋横纹抗压开裂严重,其裂隙率均值为16.6%,多数端面呈散裂状,甚至枋体有完全压溃和部分脱落的现象,华拱和泥道拱横纹抗压裂隙率均值分别为7.7%和12.0%,且拱身已有部分剥离和折断现象;五层明层各内槽转角柱上的普拍枋、华拱和泥道拱横纹抗压破坏主要为细微开裂,其裂隙率均值分别为2.9%、2.6%和2.1%,较二层明层而言,开裂较为轻微;对于木塔两层横纹抗压构件的开裂分布,二层明层多出现在塔身西南和东北方位,而五层明层横纹抗压构件在开裂方位上不明显.本研究所采用的方法可以有效获取应县木塔内部构件的横纹抗压破坏状况及开裂分布,为今后木塔修复与保护工作提供一定的基础数据.

Chuan-Dou style wooden frames (CDWFs) with different infill are used widely for residential buildings in Southwest China due to their cost-effectiveness and ease of construction. Four full-scale samples of CDWF were laboratory tested to study the contribution of different infills on its seismic behavior. They are two bare wooden frames, a frame with wooden panel infills and a frame with brick masonry infills. One bare wooden frame was subjected to monotonic load to determine the reference displacement for the in-plane Cyclic loading test in the other frame samples. The damage characteristics, ultimate lateral load carrying capacity, hysteretic behavior, stiffness degradation, strength degradation and energy dissipation were investigated. Test results indicated that the CDWF has exceptional ductility to lateral movement and good energy dissipation capacity. Both the wooden panel infill and brick masonry infill increase the lateral load resistance, lateral stiffness and energy dissipation of the CDWF system. The contribution of masonry infills to the improvement of lateral resistance capacity of wooden frames is much greater than that of wooden panel infills.

Walking-induced vibration control in wood floors is a critical issue attracting the attention of many researchers and engineers. This paper presents an experimental study applying static deflection tests, modal tests, and pedestrian load tests to a series of full-scale 12 m span tooth plates connected to wood truss joist floors with strongbacks and partition walls. A comparison of the calculation error of vibration parameters between the theoretical formula and a numerical model was also conducted. The results show that strongbacks and partition walls effectively reduce both the vertical displacement and the root means acceleration at the center of the floor under pedestrian load but increases the natural frequency. The partition wall can achieve a better vibration-reduction effect than strongbacks. The error of the finite element model is higher than that of the theoretical formula. Using the theoretical formula in engineering wood floor design is recommended.

长子小张碧云寺主殿是晋东南地区一座极具文物价值的木结构古建筑,与之有关的创建年代等若干问题还有待进一步考证.本文通过运用植物学、材料学以及年代学等多学科研究方法,对主殿现场勘查和实验室测试结果进行综合分析,基本确定主殿木构件的选材规律和病害空间分布特征,梳理主殿的修建历史脉络.研究结果对深入理解晋东南地区木结构古建筑营造的选材理念和技术工艺,科学保护晋东南地区木结构古建筑具有一定指导意义.

With the development of non-destructive testing technology and computer technology, wood non-destructive testing technology will develop towards intelligence and automation. The primary condition for development is to be able to carry out the testing of various physical properties of wood without destroying the wood itself. Wood defects refer to abnormal wood structure. Its existence will affect the quality of wood, change the normal performance of wood, and reduce the utilization rate and use value of wood. The purpose of this article is to try to find an effective detection method without damaging the original structure of the wood. It can accurately and quickly determine the defect information on the wood surface. This research mainly discusses the visual analysis of wood internal defect detection based on tomographic image reconstruction algorithm. According to the analysis of the planks to be tested, this paper determines the structural characteristics, the types of defects to be tested, and the classification standards. To analyze the principle of machine vision imaging, this paper designs a hardware experiment system for wood board imaging, by observing the collected Biyun Temple building wood images and summarizing the Biyun Temple building wood defects, surface texture features, and various appearance features in the image. Based on digital image processing technology, this paper designs a complete set of real-time timber classification and detection algorithms. The algorithm realizes the extraction of Biyun Temple’s architectural wood region, texture region extraction, and the comprehensive feature vector extraction of Biyun Temple’s architectural wood. In the image preprocessing stage, the color image is converted into a grayscale image through the grayscale processing of the image. Through the equalization processing of the histogram, the defect features in the defect image are highlighted. Through image smoothing and denoising processing, the noise points that may exist in the image are removed. The signal-to-noise ratio of the Marching Cube algorithm is maintained at a relatively high level under different noise conditions, which is about 3-4db higher than the Gaussian method with OPED. This research is helpful for the continuation and inheritance of ancient architectural attainments.

楼盖是水平方向分隔上下楼层空间的承重构件,是木结构建筑中不可缺少的一部分.但大跨度楼板阻尼小、柔性大、自振频率低,容易在人类活动与其他外界动力载荷作用下产生竖向振动,引起人们的不适;所以研究木楼盖的振动行为,找出提高振动舒适度的办法对大跨度木楼盖的推广和应用有重要作用.为了解大跨度木楼盖的振动性能,首先以12 m跨度齿板连接木桁架搁栅楼盖为研究对象,在其下部安置隔墙,比较不同支撑方式对楼盖振动模态、静载挠度、步行荷载响应与自由落体冲击响应的影响,并探讨隔墙位置和数量对木楼盖振动性能的影响规律.结果表明:下部隔墙对木楼盖振动性能的影响取决于连跨后的最大跨度.安装隔墙后,楼盖的基本自振频率提高25％以上,1 kN集中静态挠度减小40％以上;隔墙能有效降低最大跨度中央楼盖的步行振动响应,安装隔墙后楼盖步行均方根加速度减小30％以上;楼盖的振动传递主要发生在纵向,相同传递距离下纵向峰值加速度是横向和斜向的1.5倍以上.

以西南传统民居穿斗式木结构穿销中节点为研究对象,设计制作了2个足尺横向中节点和2个足尺纵向中节点模型试件,分别对两类节点进行单调加载和低周往复加载试验,得到两类节点的破坏模式、抗弯承载力、抗弯刚度、延性和耗能能力.结果 表明:横向中节点主要在榫卯挤压区域发生嵌压塑性变形以及在木销受荷区域发生弯剪变形,纵向中节点易在榫颈位置发生折断破坏;横向中节点的初始刚度较纵向中节点高,横向中节点的抗弯承载力可达纵向中节点的2倍;横向中节点和纵向中节点的滞回曲线均表现出明显的捏拢和滑移现象,横向中节点的耗能能力较强;穿斗式木结构横向中节点和纵向中节点都具有良好的变形能力,横向中节点表现出较好的延性,但纵向中节点的延性很低;纵向中节点是穿斗式木结构中的薄弱节点,需要在穿斗式木结构的安全维护中重点关注.

Due to long-term natural degradation, the surface morphology of traditional building wood differs significantly from that of modern wood. It is more combustible than modern wood and its combustion characteristics are important evaluation indicators for fire simulation and fire protection of traditional buildings. In this paper, ancient wood from six traditional buildings were tested by a surface morphology fractal method and conical calorimeter. Additionally, their combustion properties such as ignition time, heat release rate, total heat release and charring time were analyzed to determine the combustion behavior of ancient wood and their differences with modern wood. The results showed that the ignition time of the specimens was significantly influenced by the surface morphological features. The higher the fractal dimension grade of the morphological features, the shorter the ignition time. The ignition time of Ulm wood with fractal dimension class 3 was 15 s, while that of Ulm wood with fractal dimension class 1 was 23 s. Under the same fractal dimension class, the total heat release per unit time of ancient softwood was higher than that of ancient hardwood. The average heat release rates of Larch wood and Ulm wood were 66.21 kw·m−2, 72.07 kw·m−2 and 57.26 kw·m−2, 67.30 kw·m−2. The basic charring rate of ancient wood of the same species was mostly higher than that of modern wood by more than 6%, with the basic charring rate of ancient Larch wood being 0.8559 mm/min, which was 15.66% higher than that of modern Larch wood, 22.27% higher than that recommended in the European EC5 standard, and 6.87% higher than that calculated in the American AFPA. The results of the study are important guidelines for fire risk assessment and fire protection of traditional buildings.

以传统民居穿斗式木结构直榫边节点为研究对象,分析节点承载机制,并设计制作3套杉木结构直榫边节点足尺试件(对照组1套、扒钉加固1套、角钢加固1套),进行低周往复加载试验.研究结果表明:直榫边节点破坏模式主要表现为节点木材横纹压屈变形和节点拔榫,滞回曲线轮廓均呈反"Z"形状,且呈现较明显的捏缩现象.与未加固节点相比,加固节点的承载性能均有所提高;扒钉加固节点在扒钉脱落失效前提高了节点刚度、累积耗能及变形能力,角钢加固节点在穿枋断裂前显著提高了节点刚度、累积耗能及变形能力.

Waterlogged wooden cultural relics have been constantly excavated and preserved, driven by increasing public interest and upgrading archaeological technologies. Wood cells' morphology and chemical structure from waterlogged wooden relics normally undergo non-uniform degradation or changes, presenting a different "new material" from sound woods. PEG and sugars have been widely applied for consolidation. This study selected teak (Tectona sp.), the main timber species of the "Xiaobaijiao I " shipwreck, as the research object. Based on the developed sample preparation method of nonembedded nanoindentation suitable for wooden cultural relics. The PEG, sucralose and trehalose treated samples were evaluated by Nanoindentation technology (NI) and studied by infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The results showed that samples prepared by the nonembedded method could accurately measure the longitudinal elastic modulus and hardness of wood cell wall, and the PEG, sucralose and trehalose were able to significantly improve the elastic modulus of fiber cell wall respectively, by 6. 9%, 25. 4% and 29. 1% compared to untreated samples, and increase its hardness by 9. 3%, 25. 9% and 13. 6%. Infrared spectroscopy showed that PEG, sucralose and trehalose penetrated the wood, and thermogravimetric analysis confirmed that partial consolidants could enter the wood cell wall, which was the main reason for the improvement of cell wall strength. In general, sucralose and trehalose were more suitable than PEG for consolidating the waterlogged archaeological wood, with sucralose being the most effective consolidant in this research. This research provided a proven method for the accurate performance evaluation of consolidates for waterlogged wooden cultural relics such as shipwrecks and could provide a scientific basis for their consolidation and conservation.

In this paper, the mechanical performance improvement of traditional penetration mortise–tenon (PMT) connections reinforced by self-tapping screws (STSs) were experimental and numerical studied. Four unreinforced penetration mortise–tenon connections and four STS-reinforced connections were experimentally investigated under monotonic and low-frequency cyclic loading. Besides, the numerical model of PMT connections reinforced by STSs with different diameters and yield strength were established and analyzed.Their failure modes, rotational stiffness, moment-resisting capacity, ductility, and seismic behavior were studied. The experimental results indicated that the STSs reinforcements could enhance the moment-resisting capacity of the penetration mortise–tenon connection. Compared with unreinforced connections, the initial stiffness of STS-reinforced connections increased by 75% with the moment-resisting capacity increasing by 69%, respectively. Furthermore, the STSs reinforcement method can effectively restrict the pull-out of tenon during the whole loading process. Numerical simulation results showed that the yield strength of STS has little effect on the moment-bearing behavior of the connection. The diameter of STS significantly influences the connection performance, and the diameter of 8 mm is suggested.

抗侧性能参数,包括水平抗侧承载力、初始抗侧刚度和延性系数等,是评价穿斗式木构架承受水平荷载(如地震和风荷载)能力的重要指标.以穿斗式木构架为研究对象,以单调加载试验的荷载-位移曲线为例,采用国内外4项标准的方法计算穿斗式木构架的抗侧性能参数,分析不同方法的适用性.GB/T 37745—2019中未给出屈服位移和延性系数的具体定义,仅计算水平抗侧承载力和初始抗侧刚度.结果表明,采用不同方法得到的水平抗侧承载力峰值相同、初始抗侧刚度结果接近,但延性系数存在较大差异.按GB/T 37745—2019方法计算的初始抗侧刚度较其他方法偏低,JGJ/T 101—2015和EN 12512:2005切线法计算的延性系数均大于4.0,按ASTM E 2126-11计算的延性系数为2.5.根据穿斗式木构架的受力特性和荷载-位移曲线的双线性段特征,JGJ/T 101—2015和EN 12512:2005切线法规定的计算方法适用于穿斗式木构架的抗侧性能参数的计算.

现存的传统村落木结构民居,由于受风雨侵蚀及战乱、地震、火灾的破坏,发生不同程度的损伤和破坏,榫卯节点残损情况直接影响整个民居房屋结构的安全.以北方地区传统村落"四梁八柱"木结构民居榫卯节点(馒头榫)为研究对象,考虑不同残损类型及程度,制作5个足尺梁柱节点模型,通过拟静力低周往复加载试验研究其破坏模式、弯矩-转角滞回响应及骨架曲线、加载刚度、变形、强度及耗能能力等力学性能.试验结果表明:馒头榫节点破坏模式表现为榫头拔出、榫与卯口挤压变形;相比于完好节点,残损馒头榫节点抗弯承载力、加载刚度和耗能能力明显降低,且"捏拢"效应加剧;榫头松动是导致节点力学性能降低的直接原因;垂直加载方向虫蛀节点力学性能劣化程度强于平行加载方向虫蛀节点,更易导致耗能能力降低.