Ancient Wood Research Articles

Experimental and Numerical Study on Dou-Gong Joint of Ancient Wooden Structure in Qing Dynasty

ABSTRACT Three full-scale Dou-Gong specimens at column tops are made according to the Qing Dynasty “code of engineering practice,” based on the prototype of one Dou and two Sheng Jiaomaye Dou-Gong of Jiayuguan tower. The three-dimensional load-displacement curve of Dou-Gong is obtained using three-dimensional static loading tests. Furthermore, the deformation characteristics, three-dimensional compression stiffness, and three-dimensional load transfer law of each layer of the Dou-Gong are analyzed. The test results indicate that the vertical failure characteristics of the Dou-Gong are the splitting of the Flat-Fang, and there is no obvious damage to the horizontal members until toppling. The three-dimensional load-displacement relationship curve of the Dou-Gong can be simplified to a two-fold line model, vertical stiffness of the Dou-Gong is significantly greater than the horizontal stiffness, and the horizontal stiffness in the beam direction is greater than the horizontal stiffness in the Fang direction. Using ABAQUS software, a comparative analysis of the difference in mechanical properties between the Dou-Gong at the column tops and the Dou-Gong between the columns is performed. The research results can provide a theoretical basis for the structural performance safety assessment and preventive protection of the Jiayuguan tower and similar Chinese ancient wooden structures.

CONSERVING WOODEN STRUCTURE OF NEELUM AND LEEPA VALLEY, KASHMIR

Kashmir. One of its examples is the architecture of this region. Ancient Wooden Houses in different areas of Neelum valley and Neepa valley are slightly different with each other on style of construction, material, and engraved art motives. Some of the houses are more than centuries old and are fine example of culture and heritage of Kashmir. Mostly old houses are made of wood. These houses are different from each other in style and technique. A brief comparison of ancient houses of different regions will be done in this regard. Comparison includes architectural style, techniques, material, and motives related to art. It concludes that ancient houses of Kashmir need attention which is necessary for saving our culture and heritage. Keywords: Kashmir, Art of Woodwork, Neelum and Leepa Valley, Ancient Architecture, Culture Conservation.

Life Prediction Model of Wooden Structure Based on Artificial Intelligence Algorithm

The ancient wooden structure in China is a precious architectural cultural heritage in history, which has high cultural and artistic value. However, due to the influence of its own material structure and the long-term preservation and maintenance process, due to long-term loads, earthquakes, fires, man-made damage, etc., ancient buildings have suffered more or less damage, which may cause sudden failure of the structure, which seriously affects the safety of the building structure. Therefore, the research on the prediction of the life of ancient wooden structures has guiding significance for sustainable development. This paper studies the life prediction of ancient buildings and introduces artificial intelligence algorithms. By comparing the old and new of the ancient building with the damage of the various structures of the ancient building, and using a variety of methods to find a more accurate method to predict the life of the ancient building, through various aspects of research and comparison, we have discovered the variation of wooden columns and beams. The coefficients are 22.97% and 22.54%, which affect the service life of wooden members. The residual strength ratios of the compressive design strength and flexural design strength of the new material and the old material are 60.42% and 26.67%, respectively.

Study on the mechanical characteristics of Xia-Ang in the Song-style Dou-Gong set on columns

As an important node in ancient wooden buildings, Dou-Gong serves functions such as energy dissipation and overhanging eaves. Xia-Ang plays an important cantilever role in Dou-Gong. To study the mechanical characteristics of Xia-Ang, we conducted horizontal quasi-static experiments and finite element numerical simulations to investigate two typical Song-style Dou-Gong sets on columns. The difference between the two types of Dou-Gongs is the presence of Xia-Ang components. The results of mechanical experiments showed that the hysteretic curves of the two types of Dou-Gong were in reverse “s” shape under the force from the beam direction, which has obvious pinch characteristics, and the Dou-Gong components were cracked to a certain extent. Under the force from the direction of the Fang, the hysteretic curve was complete, and no obvious splitting or warping components were found in the Dou-Gong. The influence of Xia-Ang on the mechanical characteristics of Dou-Gong was mainly reflected along the beam direction, but had no effect on the Fang direction. When the Dou-Gong was pushed by the beam, the horizontal stiffness of the Dou-Gong was strengthened by Xia-Ang, and the horizontal stiffness of the Dou-Gong with Xia-Ang was increased by 29.41% compared with that of the Dou-Gong without Xia-Ang. When the Dou-Gong was under tension, Xia-Ang weakened the horizontal stiffness by 23.75%. Two types of Dou-Gong were studied using the ABAQUS finite element method. The finite element model was verified and revised by comparing the simulation and experimental results. The numerical simulation results showed that when the beam was loaded, the horizontal stiffness of the Dou-Gong increased by 28.15% owing to the presence of Xia-Ang under the action of thrust. Under tensile force, the horizontal stiffness of Dou-Gong decreased by 24.26%.

Experimental study on mechanical properties of column foot of ancient timber structures – Take the drum-shaped plinth as an example

The column foot is a typical structural feature of ancient buildings in China. The sliding rotation of the joint is related to the overall structural safety of the ancient wooden structure. In order to study the mechanical properties of column foot under horizontal force, based on the investigation of column foot forms and referring to the engineering practice of Qing Dynasty, the 1:3.2 scale models of three typical column foundation forms, i.e. Floating, Guan-jiao, and Tao-ding, were made, and the static and quasi-static loading tests were carried out. The horizontal static loading is carried out under the vertical force, and the parameters such as the angle change of the axis, the horizontal displacement load curve, the lateral stiffness and the failure mode are obtained. The results show that: during the loading process, there is no slippage of the wooden column, and the failure mode of the column foot is the overturning failure of the wooden column; The angle formed by the axis of the timber column accounts for more than 25% of the overall lateral displacement, which should not be ignored in the mechanical analysis. The hysteretic curve, skeleton curve, stiffness degradation rate and energy dissipation capacity of different column foot is obtained in the quasi-static test of horizontal low cycle repeated loading. The results show that the shape of the hysteretic loops of the column foot presents an inverse Z shape, and the area of the hysteretic loops increases with the increase of the horizontal displacement; The results show that the energy dissipation capacity of the flat Floating is better than that of the other two forms, and that of Guan-jiao is the second; The results show that Tao-ding has the strongest lateral stiffness, while Floating is slightly weaker.

Normal cloud model theory-based comprehensive fuzzy assessment of wooden pagoda safety

• It's the first time to apply normal cloud model into wooden pagoda safety assessment. • Two-way mapping of the "quantitative description-qualitative concept". • A four-level safety assessment index system. Currently the safety assessment of wood structure ancient buildings is mainly qualitative description, ignoring accurate quantitative calculation, and there are uncertain factors such as fuzziness and randomness that affect the results in the assessment process. Therefore, based on the cloud model theory of transformation between qualitative and quantitative uncertainties, this paper proposes a normal cloud model-based safety assessment approach for the protection research of wooden pagoda. A multi-level assessment system combining qualitative and quantitative indexes is constructed, and the comprehensive weight of the evaluation indexes is determined by combination weighting method. And combining with the scoring of evaluation indexes through quantitative analysis of point cloud, qualitative evaluation of experts, and published high-level papers, the comprehensive evaluation cloud model is constructed. According to the standard grade division, the criteria cloud model is constructed. And safety performance grade is determined by comparing the cloud similarity between the two clouds. Then this paper sets Yingxian wooden pagoda in China as an example, safety performance is quantified under this approach to determine its safety performance grade. The results show that the pagoda is the closest to third grade, in a certain dangerous state and consistent with the actual situation. The method takes into account the randomness and fuzziness factors, which makes assessment process more comprehensive and objective, provides a research paradigm for the safety assessment of ancient wooden buildings.

Risk Assessment and Monitoring of Termites in the Forbidden City under Global Warming

ABSTRACT Historical heritage is facing enormous challenges as a result of global warming. Termites are a significant pest in ancient wooden buildings and their area of activity is also expanding. According to historical records, Reticulitermes chinensis Snyder and Reticulitermes speratus Kolbe are the main species of Reticulitermes present in Beijing. A 40-year record of meteorological data, termite damage information published by the Chinese government and indoor environmental data show that the risk of termite damage to the Forbidden City is increasing. In the first two decades of the twenty-first century, two termite infestations occurred in the Forbidden City. Monitoring and control systems were applied immediately, the risk to each object storeroom and other termite-susceptible area was classified and monitored, and the termites were controlled successfully. With the rapid development of information technology, an advanced termite monitoring system has been introduced that is based on non-closed-loop electromagnetic induction, is fully automatic and gives remote real-time monitoring. LoRa technology was used for signal transmission between the termite monitoring station and the information collection. This signal transmission technology can overcome the signal-blocking effect of the numerous walls inside the Forbidden City, ensuring that the signal can be transmitted quickly and accurately as soon as termite infestation is detected. The non-closed-loop design allows the electronic components to be fully encapsulated, improves resistance to soil moisture and salt erosion, prolongs service life and ensures accuracy. The risk assessment and remote real-time monitoring technology introduced in this paper are of great significance for protecting ancient buildings in the cities of northern China.

Vibration reduction and isolation performance of a platform foundation and column base of an ancient wooden structure based on the energy transfer analysis

Wooden structures, as the most representative structural types of the ancient Chinese architecture, are very common and have a long history. The special construction methods adopted in ancient wooden structures, such as the platform foundations and plinth connections, enabled the ancient buildings to stand for thousands of years. However, research on the vibration reduction and isolation of the unique structures is insufficient. Thus, this paper investigates the vibration reduction and isolation performance of the platform foundation and column base of ancient wooden buildings, taking the 1500-year-old Feiyun wooden pavilion as a case study. First, using the acceleration RMS, the traffic-induced vibrations were analyzed in the time domain. It was found that the platform foundation tends to amplify the horizontal vibrations, while the column base tends to reduce them. Furthermore, background vibrations were eliminated from the measured data by using the principle of energy conservation. A frequency domain analysis of the processed data showed that the horizontal traffic-induced vibrations below 16 Hz were reduced by the platform foundation, and the column base had an obvious effect on the vibration reduction and isolation below 40 Hz. Both the platform foundation and the column base demonstrated a good effect on the reduction of traffic-induced vibrations in the vertical direction. The reported research results can be used as a basis for further studies on the dynamic performance of ancient wooden structures.

Burning Characteristics of Ancient Wood from Traditional Buildings in Shanxi Province, China

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.

Experimental and numerical study on the static and hysteretic behavior of a novel wood isolation device

This paper presents a novel wood isolation device able to reduce the whiplash effect of the wood-concrete hybrid structure under the earthquake. The device inherits the configuration of the ancient wood Dou-Gong by using some short wood components buckling each other, and makes use of sliding friction, rotary deformation of partial components and wood nonlinear deformation to dissipate energy. Both static and low-cyclic loading experiments as well as numerical simulations were performed to study the mechanical properties, hysteretic characteristics and energy dissipation capacity of the isolation device. The results indicate that the wood isolation device has sufficient vertical bearing capacity, stiffness, initial lateral stiffness and lateral deformation capacity. Under horizontal low-cyclic loading, its energy-dissipation is characterized by three stages, namely, initial deformation, horizontal sliding and post-sliding secondary deformation. Their hysteretic loops correspond to the reverse S-shape, parallelogram with sawtooth and full Z-shape, respectively. This observation indicates that the isolation device can consume some energy under frequent earthquake, and has excellent energy-dissipation capacity when the sliding occurs. Based on the hysteretic loops, the four-piecewise line model is proposed to describe the skeleton curve and restoring force model of the isolation device. The wood isolation device proposed in this paper not only inherits the essence of the ancient Dou-Gong but also exhibits excellent isolation performance, and thus has a potential application in practical engineering.

Protection of wood in ancient timber construction by surface painting of waterborne siloxane-modified polyurethane against water destroy

ABSTRACT To protect the ancient wood against water destroy, the waterborne polyurethane was modified siloxane and then painted on the wood surface. The coated surface was characterized and the surface physical and mechanical properties were tested. The results showed that the siloxane can be grafted onto the polyurethane by reacting between Si-OH groups and the end N=C=O groups. Thus, after coating on the wood surface, a network structure was formed for improvements. The polyurethane can form a layer of film on the wood surface while the siloxane can help to make a smooth coating film owing to the improved interfacial adhesion. With the increase of siloxane content, the surface became better with improved water contact angle, swelling dimensional stability, and hardness. At 3 wt% siloxane, the surface properties of the wood showed high water repellency and acceptable mechanical properties, which can be used for ancient timber protection.

Study on the Damage Diagnosis of Ancient Wood Structure in Tianshui under Traffic Excitation

Three‐dimensional finite element model of the wood structure‐foundation of the North House’s main hall in Tianshui under ground traffic excitation was established, and the damage of the first‐floor longitudinal beam of the wood structure was simulated by the finite element method. The node acceleration response signals on beams were decomposed with a wavelet packet. The wavelet packet energy curvature difference index was proposed to determine the structural damage location. The results show that the wavelet packet energy curvature difference can decide the damage location of the middle part of the first‐floor longitudinal beam, and the index value increases with the increase of damage degree. If SNR is 40 db or larger, the damage index can accurately identify the damage of ancient wooden structures. When SNR increases, the damage index will have an increasingly higher sensitivity and certain ability to resist the effect of noise. The function relation between the damage index and the damage degree is obtained to determine the structural damage degree. The study results provide a theoretical basis for the damage diagnosis of the wood structure of ancient buildings along the traffic line.

New insights into the medieval history of a non-urban territory: multidisciplinary investigations in SE Lithuania

This paper presents results of the interdisciplinary investigations into the ancient wooden construction, presumably, a well, discovered near the Pamerkiai village, south-eastern Lithuania. The study aims at ascertaining the context (specific geological-geomorphological situation and the habitation history of this territory) of this comparably well-preserved and very uncommon find. The discovered wooden construction and its environment were investigated applying a multi-disciplinary approach combining the archaeological survey, which includes analysis of the collected artefacts, the dendrological examination of the timber used for construction, investigations of the plant macroremains and pollen found in the infilling material, and the 14C dating (conventional and AMS) of the organic material; and the geological-geomorphological characterization of the site. A new perspective to gain data about the infrastructure that might have existed in the area in the 15th century is provided: the integrated and interdisciplinary research is believed to reveal the natural and anthropogenic context. A discussion on the feasibility of tracing the origins of the modern Pamerkiai village is generated. It is alternatively hypothesized that the discovered wooden construction is part of the stopover place on the highroad that has been archaeologically unexplored.

Comparative Studies of Computational Fluid Dynamic Geometric Models at Multiple Levels of Details in Evaluating Wind Action on Asian Ancient Wooden Tower

ABSTRACT Ancient wooden architectures have complex shapes and various components, thus the choice of different detail levels geometric models is a major concern in architectural heritage Computational Fluid Dynamics (CFD) simulation. This paper exhibits detailed comparisons of CFD simulation with multiple Level of Detail (multi-LoD) geometric models in predicting wind pressure on a complex high-rise wooden pagoda (tower). The results reveal that it is sensible and feasible to model the pagoda CFD geometric model by Revit and predict the wind pressure by the Realizable k-ε turbulence model. The higher LoD model makes CFD results more consistent with those in the wind tunnel test, especially on the leeward of the pagoda. The components that affect the shape of the structure (e.g., the railings, ridges, and columns) have a great influence on the wind field. Rather, the components hidden in the architectural shape (e.g., Dougong) hardly affect the wind field. This paper aims to further understanding the CFD simulation with multi-LoD geometric models in evaluating the wind effects and assessing structural safety on a high-rise wooden pagoda. It also provides a basis for the modeling and CFD analysis of ancient wooden architecture.

Inspection and evaluation of wood components of ancient buildings in the South-Three Courts of the Forbidden City

Ancient architectural wood components were evaluated in terms of mechanical properties, material color expression, ultrasonic shape, chemical components, and deformation of shape and position by comparing them with new red pine materials. The results showed that the deterioration of the surface material properties of wood components was very serious, mainly caused by weathering. The attenuation degree of the inner layer of the wood component was relatively low, and the color change of the wood was obvious, which was mainly caused by fungi. Ultrasonic nondestructive testing technology was used to detect the internal damage of ancient wood components. According to the test results, it was speculated that the root defects of pillar components were serious. Three components of wood after long-term weathering changed significantly, and lignin had been seriously damaged. This damage was reflected in the degradation of the number of aromatic groups and the changes in the nature of the group. The main wood beams in the main halls of the three yards were bent at 0 mm offset scale and unit offsets of the pillars of the four courtyards were within the safe range.

ArtClimateRoad and Revelations: Wood textures and experiential metaphors

This Multimodal Sensations article explores embodied experiential metaphors. It focuses on the salient modalities of interaction with wood texture. As both an artist and researcher, I have been particularly concerned with how social semiotic theory can be applied to my work, and specifically, how concepts from multimodal analysis can be transformed into the process of multimodal artistic creation. This article reflects on an example linking a historic anniversary, the texture of ancient wood and interaction of a local participant audience. The analysis applies a combination of concepts gleaned from the theories of Theo van Leeuwen (2016), Juhani Pallasma (2012) and Kjetil Røed (2019) to participant reflections from an art project called ArtClimateRoad.

Characteristics and possible formation process of ferromanganese beachrock in an intertidal zone of East China Sea influenced by buried ancient woods

The ferromanganese (FeMn) deposits could be found in many shallow water and deep-ocean places. Lots of studies have been performed to explore the occurrence, formation and economic value of FeMn nodules or crusts on the deep ocean floor. However, the occurrence and formation of FeMn beachrocks at the coastal zones has rarely been reported. In the present study, we collected two types of dendritic FeMn beachrock samples from an intertidal zone of Zhoushan Archipelago, East China Sea, where was significantly amended by an ancient wood layer formed during 5900–5600 cal. yr B.P. Then the microscale analysis including electron microprobe analyzer (EMPA), X-ray powder diffraction (XRD), and scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDS) were performed to study the microscale characteristics on these FeMn beachrocks. Combined with our previous studies, a possible formation process was proposed: (1) Buried ancient woods produced enough organic acids to accelerate the weathering of nearby bedrock via chemical or biological reactions; (2) The seepage water could be regarded as a bridge to connect the ancients woods and the intertidal zones, and large amounts of dissolved Fe2+ and Mn2+ can be transported to the sandy beach and intertidal zones; (3) Precipitation of insoluble FeMn oxides occurred with the involvement of microbial processes and direct inorganic chemical sorption under mixing of seepage water and seawater; (4) After that, these FeMn oxides would experience nucleation, crystallization growth, and then diagenetic process to form the FeMn beachrocks. The present study spotted a light on the microscale features, formation process and biogeochemical cycling of nearshore/coastal diagenetic Fe-Mn deposits.

Challenges for the restoration of cultural values in UK woodlands

The eco-cultural nature of ancient woods and forest landscapes in the UK is well-established. Furthermore, the loss of cultural knowledge and memories as traditional management reduced and in many cases ceased during the twentieth century presents challenges for site conservation and that of the eco-cultural resources. Additionally, both tangible and intangible cultural heritage of these landscapes are seriously threatened and cultural severance is a major driver of ecological change and species loss.This paper takes a regionally-based case-study of these eco-cultural landscapes and their biocultural resources as evidenced by archaeology, archival sources, oral histories, and ecological field survey. This information provides detailed time-lines for specific sites from Domesday to the twenty-first century.Finally, site assessment and evaluation, and practical management implementation are considered. Issues of lack of recognition of biocultural heritage and hence of inadvertent or unknowing damage are discussed. Lack of accepted evaluation processes or effective kite-marking for sustainable forest products presents significant problems.

Experimental Study on the Fire Resistance Performance of Partition Board under the Condition of Small Fire Source

Fire safety of ancient wooden buildings is one of the most important issues in the world. In this paper, partition boards with different thicknesses from 15 to 25 mm were heated by a 15-cm-diameter pool fire and a methane Bunsen burner. The temperatures and the carbonization rate of partition boards were measured and analyzed. The results show that when a pool fire was used to heat the wood sample at a distance of 30 cm, two flames appear on the sample surface. When a Bunsen burner heats the sample, the sample is burned until the center point is burned through. The thickness of the sample is increased by 5 mm, and the acceleration time of the temperature rise rate at the center is doubled. Under the condition of a pool fire, the thickness of the sample is increased by 5 mm, and the average carbonization rate at the center point is reduced by 40%. Under the condition of Bunsen burner, the average carbonization rate of the center point decreases exponentially when the thickness of the sample increases by 5 mm. In the case of the same fire source, the carbonization rate of the samples with different thicknesses has the same change trend in the horizontal and vertical directions. Compared with the pool fire, the burn-through time of the center point of the sample is reduced in the case of the Bunsen burner for a sample of the same thickness, and the average carbonization rate of each measuring point increases.

Wind Effect Analysis of a High-rise Ancient Wooden Tower with a Particular Architectural Profile via Wind Tunnel Test

ABSTRACT Wooden architectural heritage is a symbol of architectural heritage worldwide and has high historical, cultural, and scientific values in Asia countries (e.g., China, Japan, Korea, and Nepal). Wooden pagoda (a kind of tower with multiple eaves in East Asia) serving as one important member of wooden architectural heritages suffers from damages that are caused in various natural disasters such as windstorm, fire, and earthquake due to its long-time service and considerable size. Wind caused damage is one of the most common damages caused by natural disasters, making the structural safety of high-rise wooden pagodas under wind action a major concern in architectural heritage protection. This study analyzes the wind effects on the Yingxian wooden pagoda in China by a wind tunnel test and computes the wind loads on the wooden pagoda. The wind characteristics of wooden the pagoda in a wind tunnel test are presented and compared with modern buildings and other types of wooden architectural heritages. Additionally, this study attempts to analyze the difference of the computed wind loads from the wind tunnel test and from the full-scale measurement. The results reveal that the wind pressure distribution at certain locations are similar to those of modern buildings or other ancient wooden architectures. However, the wind pressure distribution at some locations are distinctive due to the complexity of the architectural profile (e.g., the boundary of the pagoda is an octagon in bird view). The wind load from wind tunnel test are in good agreement with those in full-scale measurement with less than 14% error. This study extends the understanding of the wind effects and structural safety assessment on the high-rise wooden pagoda, providing useful guidelines for structural design (e.g., wind-resistant design) and for structural health monitoring (e.g., service maintenance) to monitor not just the specific wooden pagoda but also other high-rise pagodas, especially the those with top views of octagonal shapes.