Bracket Sets Research Articles

Research on wind pressure characteristics of traditional timber buildings: a case study of the main hall of Shisi Temple

Traditional timber buildings are sensitive to wind action. Studying the wind pressure characteristics is the premise for the preventive conservation of traditional timber buildings. To investigate the computational fluid dynamics (CFD) numerical simulation method for wind pressure on traditional timber buildings, a typical traditional timber building, the main hall of Shisi Temple, is chosen as a case to carry out the study. A comparative analysis is conducted to examine the effects of curve simplification of the roof slope, as well as the Dougong (bracket sets) and roof tile components, on the numerical simulation results of wind pressure on the building surface. Additionally, simplification schemes of geometric modeling are provided for the efficient and accurate simulation. The results indicate that moderate simplification of the roof curve has a relatively minor impact on the overall calculation of wind pressure, and the difference between the drag coefficients of the simplified model and the accurate model is no more than 3%. However, excessive simplification can lead to distorted simulation results, and a three-segment curve simplification method is recommended for roof cornices. The influence of Dougong on the wind pressure calculation results is negligible (within 5%), whereas roof tiles significantly reduce the drag coefficient, with an impact of over 30% at various wind directions. The impact of roof tiles on wind pressure distribution in traditional timber buildings lies in their alteration of the building aerodynamic shape rather than an increase in roof thickness. The findings can provide a basis for assessing the wind resistance of traditional timber buildings and helpful insights for improving the efficiency of wind pressure analyses of traditional timber structures.

Reassessing the Proportional System of Joseon Era Wooden Architecture: The Bracket Arm Length and Width as a Standard Modular Method

Previous research has agreed that standard modular methods in Song Yingzao Fashi and Qing Gongcheng Zuofa were not applied to Korean wooden architecture. This study notes the size of bracket arms as a standard modular method by investigating the proportion systems of Sungnyemun, Paldalmun, and Heunginjimun Gates, the official government buildings of the Joseon Dynasty. The purlin direction bracket arms in the intercolumnar bracket sets apply a proportional system in the ratio of a regular integer relationship to the front and side facades and building height. Challenging current assumptions, the application of the bracket arm width as a modular rule is divided into more subdivided values than the measurement units. A particularly important finding is that, unlike the height of the bracket arms, the width and length of the brackets are standard members that determine the height of the side facades. This is very similar to the official government building styles in the Song and Qing Dynasties, premodern China. Therefore, this study is meaningful in reassessing wooden frame structures of the Joseon era, deriving parametric measuring rules universally applied in East Asia to provide basic data useful for heritage conservation.

Seismic evaluation of a traditional Chinese palace-style timber structure

To assess the seismic performance of a traditional Chinese palace-style timber structure, an extended discrete element method (EDEM) model has been established. The model has been applied to analyze a single-story and five-bay timber-frame palace architecture, where sliding isolation of the column foot, semi-rigid connections of mortise and tenon joints, and damping characteristics of bracket sets (known as Dougong in Chinese) have been considered. The study investigates the dynamic characteristics, seismic responses, and structural vulnerabilities of the palace building. Results show that an error of the natural frequency between the EDEM model and results from code-recommended empirical formulas is only 6.88%, highlighting the rationality of the EDEM model. Furthermore, the relative displacement response of each position increases with the increment of inputting acceleration of seismic waves. The inter-structural layer drift of the column-beam frame is the largest and that of the roof truss is smaller, while Dougongs are the smallest. The likelihood of moderate damage is highest during a small earthquake, while the structure is prone to severe damage under a medium earthquake, The structure is susceptible to collapse under a large earthquake.

STRUCTURE AND DECORATION ART OF DOU-GONG BRACKET SETS AND ITS CULTURAL COMMUNICATION

A system of brackets inserted between the top of a column and a crossbeam (hereinafter referred to as Dou-Gong Bracket Sets) is a unique and important structural component in traditional Chinese architecture. It is used to represent the connotations of traditional Chinese culture. To begin, this paper discussed the meanings of Dou-Gong Brackets Sets and their various features at each stage. At the same time, it thoroughly examined the system's structure and decoration, as well as its changes over time. Second, this paper expanded on its connotations of traditional Chinese culture. Then, a Dou-Gong Brackets Sets is chosen to design a 3D digital simulation game, and the game interface and interactive module are created based on the game design's participation and dissemination. The interface design with Chinese charm, visual function, and simplicity is created using design psychology and emotional design principles. This study evaluates and tests the user experience as well as the effect of cultural and educational communication of the Dou-Gong game, and it confirms that digital communication means play an irreplaceable role and significance in Dou-Gong communication.

Design Method of Zen-style Bracket Sets Recorded in the Japanese Carpentry Manual Kamakura Zoei Myomoku (Part 2): A Comparative Study with the Chinese Manual Gongcheng Zuofa Zeli – A Secondary Publication

This paper looks into Zen-style bracket composition and design methods recorded in Kamakura Zoei Myomoku, an architectural manual kept by the Kawachi family, the hereditary carpenter family for the Kenchoji Temple in Kamakura, Japan from the 13th to 19th century. It then makes a comparison with Gongcheng Zuofa Zeli (Engineering Manual for the Board of Works), a Chinese architectural engineering manual in the Qing dynasty (1644‒1911). The study results indicate that the cross-sectional dimension of bracket is used as the base measurement unit in both China and Japan, while the use of equidistant baseline and rafter dimension as base unit are considered to be Japanized improvement.

Design Method of Zen-Style Bracket Sets Recorded in the Japanese Carpentry Manual Kamakura Zoei Myomoku (Part 1): A Comparative Study with the Chinese Manual Yingzao Fashi – A Secondary Publication

Through a comparison with the traditional Chinese manual Yingzao Fashi (Technical Treatise on Architecture and Craftsmanship), this paper analyzes the composition and design methods of Zen-style bracket sets described in the Kamakura Zoei Myomoku, a technical document inherited by the Kawachi family of carpenters at the Kenchoji Temple in Kamakura, Japan from the 13th to 19th century. As a result, the paper suggests that there were some similarities between Chinese and Japanese modular designs, which both used the cross-section of Gong as the basic unit, while other techniques like the use of a baseline for equal spacing and the rafter size as the basic unit, are considered to be Japanese innovations.

The excavation of the 2018 Xuewei tomb No. 1 in Reshui cemetery, Dulan County, Qinghai

Abstract After a looting case was cracked on March 15, 2018, the Institute of Archaeology of the Chinese Academy of Social Sciences and other organizations promptly conducted a rescue excavation of the looted tomb No. 1 at Xuewei. The tomb is the mausoleum of the king of Touyu-houen under Tubo’s rule in the mid-eighth century CE. It consists of two parts: the tomb compound aboveground and the underground structure. The former includes enclosure walls, sacrificial buildings, a mound, and a cloister. The latter consists of the entry ramp, the tomb pit, the screen wall, the tomb corridor, and the tomb chambers comprised of a main chamber and four side chambers, which is consistent with the document that recorded an “Inner-Mound Shrine of Five Gods.” The main chamber includes mural paintings, red-colored representations of wooden bracket sets, painted double coffins, a coffin platform, and an offering altar. A large number of artifacts predominated by goldware and textiles were uncovered. Amongst them, a silver seal bearing the inscription “seal of the King of Achai, the nephew” provides critical evidence for the confirmation of the status and ethnic identity of the tomb occupant.

Analysis on the mechanical performance of Dougong bracket sets under eccentric vertical load

This paper investigates the mechanical performance of Dougong bracket sets under eccentric vertical loads. Three full-scale Dougongs under different eccentricities of loads are tested. The failure patterns, load–displacement curves, stiffness analyses, load distribution, displacement analyses, and the load distribution in the tail of the Taojian-Beam are discussed. Test results indicate that the failure pattern of the Dougongs under the eccentric load is brittle failure, and bearing capacities significantly decrease. Elastic stiffness of Dougongs under eccentric loads is greater than that of Dougong under axial load, while plastic stiffness of all Dougong specimens is similar. The load eccentricities significantly change the load transferring path in the Dougongs and aggravate the rotation of timber members in the width direction. On this basis, stress and strain analyses are conducted by finite element calculation. Parametric analyses considering eccentricities of vertical load, compressive strength, elastic moduli, and friction coefficients on the mechanical performance of Dougongs are also discussed. Parametric studies show that as the eccentricities of the load increase, the elastic and plastic stiffness decrease. However, as the compressive strength, elastic moduli, and friction coefficients increase, ultimate displacement decreases, and stiffness of the Dougongs obviously increases.

Mechanical performance of inclined Dougong bracket sets under vertical load: Experimental tests and finite element calculation

This paper presents an investigation on the mechanical performance of inclined Dougong bracket sets under the vertical load. Initial inclination angles of Dougongs are determined based on material test results and embedment mechanism theories. Four full-scale Dougongs with different initial inclination angles are tested under the vertical load. The failure patterns, load-displacement curves, load distribution and displacement analyses are disclosed. Moreover, finite element calculation is conducted, model validation, stress and strain analyses are illustrated. Parametric analyses considering initial inclination angles of Dougongs, compressive strength and elastic moduli of wood, and friction coefficients between embedded surfaces are also carried out. The results indicate that inclined Dougongs under the vertical load behave similarly to a timber block under compression in the perpendicular-to-grain direction. Increasing the initial inclination angles can enhance vertical stiffness to some extent, but the bearing capacities of the inclined Dougongs are not promoted. For inclined Dougongs, part of the load transferred in the width direction is gradually carried by other components in the overhanging direction. The inclined Dougong rotates under the vertical load, and as the load increases, the overall rotation becomes more obvious. Parametric studies show that as initial inclination angles increases, plastic stiffness decreases to some extent. With the increment of compressive strength, elastic moduli, and friction coefficients, ultimate displacement decreases but plastic stiffness obviously increases.

Precast segmental bridge columns with resettable sliding joints —— An inspiration from ancient Chinese pagodas

The construction of bridge substructures by in-situ assembly of precast concrete segments provides significant benefits in quality control and economy, but their seismic stability is always a concern. Incidentally, prefabricated components have long been used in building tall pagodas for thousands of years in China. Among the pagodas that have survived numerous centuries, the timber pagodas are believed to be assembled structures of great research value in respect of seismic isolation design. There is indeed a certain degree of similarity between the timber pagodas and the proposed precast segmental bridge columns with resettable sliding joints. The smart seismic isolation mechanism in multi-storey timber pagodas with mortise-tenon rocking columns and distributed bracket sets has the following key features: (a) high lateral flexibility, (b) smart energy dissipation system, (c) guided self-centring behaviour, and (d) measures to enhance vertical stability. Actually, the resettable sliding joints in the present precast segmental bridge columns are so designed and distributed to obtain a similar seismic isolation mechanism. Time-history simulation results of seven conceptual models show that the columns with resettable sliding joints outperform the other counterparts especially in respect of (a) the overall seismic isolation between the top mass simulating the deck and the shaking ground, (b) the control of residual sliding displacements at segment interfaces, and (c) satisfactory energy dissipation performance.

Seismic Performance Evaluation of a Roof Structure of a Historic Chinese Timber Frame Building

ABSTRACT This paper presents a finite element modeling method for a prediction of lateral resistance and seismic response of the roof structure of a historic Chinese timber frame building. Force-displacement relationships of straight tenon joints, Mantou tenon joints, and Dougong bracket sets are calibrated by experimental results. In-plane and out-of-plane resistance analyses have been carried out, and force-displacement relationships and stress contributions are obtained. Acceleration and displacement responses are attained and adopted for the seismic performance evaluation of the historic roof structure. Results show that the overall in-plane and out-of-plane hysteresis performances of the roof are poor and energy dissipation abilities are weak. The seismic responses of measuring nodes are close under the same seismic excitation. As the seismic excitation increases, peak responses of all measuring nodes increase. Dougong brackets and mortise-tenon connections dissipate large seismic energy under strong excitation, and seismic responses (acceleration and displacement responses) of the roof structure are significantly reduced. The maximum drift angles of the entire roof truss are found to approach 1/2500 rad, demonstrating that the roof structure has good integrity.

Influence of component damage on the mechanical performance of bracket set joints in ancient timber structures

Ancient Chinese heritage buildings have high historical and artistic value. The bracket set in heritage buildings plays an important role in transferring and bearing load. However, over time, damage appears in these heritage buildings, which is especially serious in bracket sets. As damage seriously affects the safety and stability of the structure, studying the mechanical properties of the damaged bracket set and analyzing its influence on the entire structural system is vital for protecting ancient timber structures. This paper studies the influence of two kinds of damage on the mechanical properties of the bracket set. The model experiment results show that the force area reduction of the components in bracket sets has a distinct influence on the bearing and deformation capacities of the bracket set, with the impact on the stiffness of the bracket set being most significant. When damage occurs in the first layer of the Gong, the effect on the strength and the stiffness of the bracket set is the greatest. Numerical simulation shows that although the lateral displacement of the component will affect the seismic performance of the bracket set, the energy consumption ability remains good. The sidesway of the Cap Block has the greatest influence on the seismic behavior of the bracket set.

Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty

ABSTRACTWooden columns surmounted by bracket sets are a key element of the great buildings of Imperial China and have received a tremendous amount of attention from scholars and architectural professionals. This article revisits the question of their symbolic function during the Han dynasty (206 bce–ce 220). In addition to their structural role, column and bracket sets fulfilled important social and cultural needs related to the representation of celestial and spiritual qualities. Understood variously as pillars of heaven, gates of heaven, the constellations, Kunlun Mountain and celestial plants, column and bracket sets engendered a rich iconography that served to bond architecture closely to the heavens.

Study on earthquake resistance behaviors of Taihe Palace by simulation

Taihe Palace in the Forbidden City in Beijing is the largest scale as well as highest level of Chinese ancient palace buildings. To effectively protect Chinese ancient buildings, the Taihe Palace is taken as example to study its earthquake resistance performances. Simulation means is considered for analysis. Based on typical constitutions of Taihe Palace such as freestanding column root, tenon-mortise connection between beam and column, bracket sets (tou-kung), heavy roof, filler wall and so on, its finite element model is built by ANSYS program. By modal analysis, response spectrum analysis and time-history analysis, its dynamic characteristic and seismic performances are discussed. Results show the basic frequency of Taihe Palace is 0.85 Hz, its main modes are of translation in level directions. There is little relation among main modes. Under 8 degree intensity of of frequently occurred earthquakes, internal forces of the building are within permission scopes, which means it is not destroyed. Under 8-degree intensity of rare occurred earthquakes, its maximum deformation value is within the permission scope, reflecting it does not collapse. The constitutions such as freestanding column root, tenon-mortise joint, bracket sets and so on are helpful for earthquake resistance. Thus the Taihe Palace has good aseismic performances.

Fast Nonlinear Analysis of Traditional Chinese Timber-Frame Building with Dou-Gon

ABSTRACT This article presents a study of the applicability of fast nonlinear analytical (FNA) models in predicting the global response of Chinese traditional timber-frame building with Dou-Gon under seismic excitation. Efforts are made to overcome challenges in establishing simplified calculation models, and the corresponding dynamic equations are derived considering the mechanical behavior of sliding column root, mortise-tenon joint and Dou-Gon (bracket sets). Furthermore, nonlinear time-history analysis is conducted under different seismic excitations. Through a verification study, a good correspondence is obtained with previous shake-table test results. Seismic response analysis is also conducted to investigate the energy dissipation of column root sliding, mortise-tenon joint, and Dou-Gon. Subsequently, peak responses of column root and roof under increased values of peak ground acceleration (PGA) are also analyzed. And then, seismic isolation ability and damping characteristics of the model are discussed.

Precision of the dimensions of orthodontic bracket slots – systematic review

Abstract Introduction: The aim of this study was to revising and presenting results of in vitro studies referring to the precision of the dimensions of orthodontic brackets’ slots. Materials and methods: Search was proceeded for studies describing results of measurements of the dimensions of orthodontic brackets slots performed with the use of various available measuring instruments. Brackets from various manufacturers were taken into consideration. Search was performed in Pub-Med and Google Scholar. The following keywords were used: „bracket slot”, „orthodontic bracket slot dimension”. Studies were included, if they based on two separate measurements: at the slot opening and along the slot bottom. Studies were rejected if they described an analysis of bracket slot structure or roughness without providing slot dimensions. Results: Finally, 13 papers were selected from PubMed and 9 papers – from Google Scholar (all the papers from PubMed were found in Google Scholar as well). All the studies analysed, regardless of the method of measurement and material used for the manufacturing of orthodontic brackets revealed, that slot dimensions were higher or lower than the declared standard size. Moreover, analysis of slot appearance provided interesting information pertaining to the shape of bracket slots, e.g. parallelism, convergence or divergence of their walls. Conclusions: Basing on the review it can be stated that orthodontic brackets are characterized by imperfections that may characterize single brackets, bracket sets or series. They may potentially influence the process of three-dimensional aligning of individual teeth during orthodontic treatment.

AMS 14C dating and wood identification in ancient timber structures in Shanxi Province, China

Shanxi Province in the north west of China is one of the centres of ancient Chinese civilization. Archaeological records from this region are a valuable legacy of ancient culture in China. Many historical buildings have been preserved up to the present time. Forty-one archaeological wood samples were taken from twelve timber structures that are in the northern, central, southern and south-eastern regions of Shanxi Province, China. The AMS 14C dates were calibrated and compared to the dates in the historical records to establish accurate calendar dating of the timbers using radiocarbon analyses, when it came to the construction of the buildings and the times when maintenance work was carried out on them. The reusing of certain timbers was investigated. All the samples were identified using a microscope; they were identified as eleven timber-tree genera. The most common species used for the ancient buildings concerned was Ulmus, followed by Larix, Populus and Quercus. While guaranteeing quality and utility, these taxa were mostly used in the columns, flower arms, cap blocks, bracket sets etc. The principle and trend of the wood selection involved were pointedly restricted by means of transportation, because the ancient timbers used in the buildings were mostly gathered from the local wild wood resources in the areas nearby.

Production and Enshrinement of Arhat Paintings during the Late Joseon Dynasty

Arhats are those who attained arhatship, the highest level a Buddhist monk can achieve through the practice of asceticism. They have been worshiped by humans since the early period for their supernatural powers that served to protect Dharma and provide benefits to ordinary people. Paintings of arhats have long been popular in Korea, but most of the remaining examples date to the late Joseon dynasty. In the late Joseon dynasty, paintings of the sixteen arhats and the solitary saint were produced in large numbers and murals of arhats adorned many spaces inside a temple. At that time, arhat paintings were commissioned by Buddhist monks and laypeople and produced by Buddhist monk painters, who were open to the sharing of iconography but influenced the style of their works with personal artistic characteristics. As a result, painters could freely demonstrate their signature styles in arhat paintings, which allowed them considerable freedom of expression. A set of paintings of the sixteen arhats, in particular, sometimes features a combination of different painting styles, indicating that several master monk painters participated in the production. In the late Joseon dynasty, paintings of the sixteen arhats were generally enshrined in arhat halls, while in comparison paintings of the solitary saint were installed in relatively diverse areas around a temple. Most of the murals of arhats were painted in the upper portions of the walls of main halls dedicated to Buddhas. Paintings of the sixteen arhats and the solitary saint mainly served as objects of worship inside a temple hall, and murals of arhats, especially those on the spaces between bracket sets or over naemokdori bars below the ceiling, are more likely to have provided adornments to protect Buddhas and the Buddhist world. Arhat paintings of the late Joseon dynasty include several subcategories within the genre and served various purposes. They are significant in that they shed light on the working methods of the Buddhist monk painters of the time.

Seismic Damage Evaluation Model of Chinese Ancient Timber Buildings

Lack of the evaluation method for timber structure has been developed as a critical problem in decades to protect the ancient timber building. Therefore, it is essential to conduct an intensive study on the failure mechanism of the ancient timber building in order to precisely predict the structural failure prior to earthquake and evaluate the seismic damage and structure maintenance after the earthquake. Based on the test of dovetail column-frame and bracket sets under low reversed cyclic loading and the shaking table test of overall structure, the “potential of destruction-resistance” of the two energy-consuming components under low reversed cyclic loading and the energy dissipated of each energy-consuming component under various earthquake conditions were investigated. A seismic damage evaluation model of the energy-consuming components/structure based on the “potential of failure-resistance” and the energy dissipation was developed. With the failure coefficient, the damage level of each energy-consuming component and the overall structure can be evaluated respectively. Finally, the seismic damage evaluation model is validated by the experiment result.

Typical Aseismic Constitution Problems of Tou-Kung in the Forbidden City

To protect Chinese ancient buildings, tou-kung (bracket sets) in the Forbidden City in Beijing were taken as example to study their aseismic constitution problems and strengthening methods by survey as well as analysis methods. According to constitution characters and mechanical performances of these tou-kungs, their typical aseismic constitution problems were summed up, causes for the problems were discussed, and strengthening advices were proposed. Results show that typical aseismic constitution problems of these tou-kungs include decay, crack, deflection, slack and disengage of parts and so on; main causes relate not only to constitution, construction and bearing performances of bracket sets, but also material properties of wood; besides, effectively strengthening methods for these tou-kungs include reassembling, gluing, iron components connection and so on.