Traditional Timber Structures Research Articles

Axial compression behaviour of retrofitted long timber columns

Spliced joints are used widely in retrofitting traditional timber structures, especially in heritage conservation applications where as much original material as possible needs to be retained. However, in practice this method is mainly applied based on experience, and there is a lack of understanding and quantification of the mechanical behaviour of retrofitted timber members. This article presents an experimental study on the axial compression behaviour of splice-jointed timber columns. The splice joints are reinforced by steel jackets, steel jacket with adhesive, ear hoops and carbon fibre–reinforced polymer wrapping, respectively. The performances and effect among these enhancement methods have been compared based on the failure modes and deformation, stiffness and strength measurements. The results show that the load-bearing capacity of the spliced columns reinforced with steel jacket and further enhanced by epoxy adhesive could recover about the full capacity of the reference columns. The load-bearing capacity of the retrofitted columns reinforced by ear hoops could reach 91% of the reference specimens. The weaker rigidity of the carbon fibre–reinforced polymer joints tends to affect negatively the loading capacity of the retrofitted columns.

Hysteresis behavior of traditional timber structures by full-scale tests

To study the seismic response of a traditional timber structure in China, a full-scale model capturing the main characteristics of a representative ancient Chinese wooden structure in Song Dynasty (960–1279 AD) was established and tested considering three different levels of vertical loads, which is one-story sophisticated timber structure consisting of four columns and Dou- gong sets. A swing column was used to apply the synchronous horizontal force. Tests under the low-cyclic loading were performed considering three levels of vertical load to reveal the hysteretic behavior of the historic buildings. Based on the observed characteristics from restoring forces, the ancient wooden structure appears to have a good ductility despite of its low inherent energy dissipation capability. Based on the test results, the following relationships are established: loads versus displacements with key turning points, the loads at the key points versus the roof weights, the displacements at the key points with the column diameter, and structural stiffness versus ductility. Finally, a limiting value of drift angle for structural design and the equivalent viscous damping and ductility factor for dynamical response analysis are proposed.

Representing Korean architecture in the modern West: two Korean Pavilions from 1960s international expositions

The Korean Pavilions for the 1964 New York World's Fair and the 1967 Montreal International Exposition were designed by Chung-Up Kim (1922-88) and Swoo-Geun Kim (1931-86) respectively, two pioneers of modern architecture in Korea. Both pavilions’ designs raise a widespread architectural question about the modern representation of tradition. In contrast to earlier pavilions in Chicago (1893) and Paris (1900) that replicated poorly supposedly ‘authentic’ Korean architecture, these 1960s entries modernised traditional architecture from their architect's creative viewpoint. While Chung-Up Kim noted the formal qualities of the Korean sloped roof, especially its curvilinearity, Swoo-Geun Kim emphasised the traditional timber structure underneath the roof, exaggerating its horizontal layers. In other words, the former's pavilion was more expressive and sculptural, which reflected the architect's Corbusian and even Aaltoesque tendencies. Conversely, the latter pavilion was more logical and systematic. However, Swoo-Geun Kim's interpretation of tradition was also ultimately about the form, though he soon became more interested in space. With regard to the form, the two Kims shared the fundamental idea that the past must not be imitated as it was, but re-created in a modern sense. This underlying argument is reflected in the contemporary ‘debate on tradition’ ignited by the design competition for the National Museum of Korea in 1966. It also relates to to the ‘Japanese-Style Scandal’ of 1967 in which Swoo-Geun Kim suffered for his design of the Buyeo National Museum, 1965-68, due to the inclusion of Japanese nuances in the design of the Montreal Pavilion. Swoo-Geun Kim's later high-tech style pavilion for the 1970 Osaka Expo, alongside recent projects by Minsuk Cho in Yeosu (2010) and Venice (2014) has more recently suggested alternative ways to represent Korea in architecture. Therefore, these two pavilions from the 1960s can be understood as unique inflection points in Korean architectural history.

伝統木造T字型仕口の回転めり込み特性と定式化

The important structural elements of traditional timber structures in Japan are rotational resistances of column-beam joints. The restoring forces characteristics of their structures depend on the rotational resistances of the joints. Therefore, the elasto-plastic restoring force characteristics of embedment of joints are the most significant in order to evaluate the seismic performances of traditional timber structures. The authors have already made clear the embedment mechanism of crosspiece joint which is the most basic and their rotational center is easily understood, and formulated the elasto-plastic restoring force characteristics of embedment of joints by using Elasto-plastic Pasternak Model (abbreviated to EPM). However, there are many types of joints and their resisting mechanisms may be different. The crosspiece joint is the most simple and basic because of the symmetry in rotational mechanism. The formulation of restoring force characteristics of T-type joint including Sashikamoi has not been made because it is difficult to find the rotational center. Of course, it is possible basically to find the rotational center based on the geometrical and force conditions. However, the solution is complicate and it is difficult to express the position in a closed form. Therefore, the authors assume the rotational center by T-type joint loading test results, focusing on the movement of the center of joint and rotational center. They assume the rotational center on the surface of Nuki (Fig. 11) and under the edge of Sashikamoi (Fig. 12). Then, the restoring forces characteristics are formulated based on the EPM, and parameters are determined in order to trace the restoring forces characteristics of the test results. The loading tests are carried out as follows; The test setup is shown in Fig. 2. The column is made of steel and test specimens of Nuki and Sashikamoi are made of Japanese Cypress. Nuki consist of A, B, C, D, E, F and G types and Sashikamoi are S and K as shown in Fig. 3 and Table1. The test results of joints are shown in Photo1～Photo4. The movement of the center of joint A-2 and S-2 are shown in Fig. 6 and Fig. 7. Then, the rotational center C is searched from the geometrical relation between the center of joint and rotational center. Distribution of the rotational center C is plotted in Fig. 9 and Fig. 10. As a result, the rotational center C mostly situates on the surface for Nuki, and under the point V for Sashikamoi. Thus, the authors assumed the position of the rotational center and rotational embedment models are shown in Fig. 11 and Fig. 12. The EPM formulation of the Nuki and Sashikamoi are proposed in equations from (4) to (36). The restoring force characteristics of test results are simulated based on the EPM formulation and obtained the EPM parameters as shown in Table2 and some examples of simulated results are drawn in Fig. 13～Fig. 16. As a conclusion, the simulated results of M-θ relations are fairly well comparing with the test results and the proposed formulations are confirmed to be adequate.

伝統木造の束の回転めり込みメカニズムと定式化

The important structural elements of traditional timber structures in Japan are rotational resistances of column-beam joints. The restoring forces characteristics of their structures depend on the rotational resistances of the joints. Therefore, the elasto-plastic restoring force characteristics of embedment of joints is the most significant in order to evaluate the seismic performances of the traditional timber structures. The authors have already applied Pasternak Model (abbreviated to PM) to the embedment and established the formulation of embedment mechanisms of partial compression of wood, which is the most appropriate embedment mechanical model for embedment problems. Furthermore, they developed the Elasto-plastic Pasternak Model (abbreviated to EPM) for the elasto-plastic embedment mechanism considering the strain hardening behavior. However, there are many types of joints and their resisting mechanisms are different. Thus, the mechanisms of different types of joints should be made clear. The authors have already established the formulation of crosspiece joint applying the EPM of the mechanism and confirmed the formulation based on the static loading tests. In this paper, the authors focus on the strut which has not been considered as a structural element so far, and propose the formulation of embedment mechanism of the strut, as a model of rotational embedment under the constraint conditions. Then, they carried out loading tests of the struts, and obtained their restoring forces characteristics. The loading test of two types of struts were carried out; one is Y-series (six specimens) which support the floor beams standing on the base stone. The other is T-series (three specimens) which stand between two beams, called, “Taihei tuka”. The dimentions of the strut are: depth:120mm, breadth:120mm, height:280mm. Beams depth:180mm(Y-1～3) and 90mm(Y-4～6), and 150mm (T-1～3). All species of specimens are Japanese cedar (Sugi). The test results showed that the maximum horizontal resistances of Y-1～3 were 8～11kN, the maximum normal loads were 36～50kN. The maximum horizontal resistances of Y-4～6 were 6～7kN, the maximum normal loads were 18～28kN. T-1～3 were the maximum horizontal resistances of 12kN, the maximum normal loads were 48～53kN and had the large deformability up to 200mm. The resisting mechanism of strut joints due to horizontal loads is “Diagonal Effect” which push up the beam, rotating and embedding into the beam in accordance with the rotation of the strut. The mechanism is due to geometrical fact that the diagonal line of the strut is longer than the height of the strut. Another mechanism is the distance between beams decreases due to inclination of column. The same mechanism is found in short beams between inclined columns and panel walls within the frames. The authors considered the mechanism of struts is rotational embedment of strut into beams under the constraint conditions and proposed Elasto-plastic Pasternak Model formulation established by the author, in order to analyse them appropriately. Then the formulation is discussed and verified by the simulation based on the Elasto-plastic Pasternak Model formulation. As a result, the deformability is very large and the strut should be considered as a structural element for exact seismic estimation of traditional timber structures.

Historiography of Mosque Architecture in Malaysia: Analysis of Texts by 5 Authors

Malaysian mosques exhibit remarkable variations, ranging from humble traditional timber structures to massive modern complexes. This evolution has been studied by numerous historians, architects, and academicians resulting in a steadily expanding historiography of mosque architecture. However, this body of work on the history and development of local mosques has never been formally studied in detail as a whole. Therefore, this paper focuses on 2 major aspects: first, identifying general research approaches present in the historiography of mosque architecture in Malaysia, and second, classifying the formal elements and characteristics used to describe the architecture of local mosques. Based on selected texts from 5 Malaysian authors, it was identified that these works are descriptive studies that are primarily structured on a combination of chronological, stylistic, cultural, geographical and typological approaches. Additionally, descriptions of mosque architecture by the authors were based on a set of formal elements and characteristics which falls into 5 distinct categories: i) typological element, ii) spatial organisation, iii) roof form, iv) building technology, and v) design articulation. These results reflect the complexity of mosque development in Malaysia and the multiple angles that are possible to holistically examine them. This paper also discusses 3 significant aspects embedded within the study of mosque architecture in Malaysia, covering unique elements and characteristics of local mosques, followed by issues related to language, conceptual, and factual ambiguity, and finally on the complexity of mosque classifications.

Retraction Notice: Evolution and Composition of the Traditional Timber Structure Column Bases in the Southern Region of China - A Case Study of Shaoxing City

Retraction Notice: Evolution and Composition of the Traditional Timber Structure Column Bases in the Southern Region of China - A Case Study of Shaoxing City

Damage Investigation of Traditional Timber Structure in the 2016 Kumamoto Earthquake

Damage Investigation of Traditional Timber Structure in the 2016 Kumamoto Earthquake

Evaluation of Structural Performance and Dynamic Characteristics of Korean Traditional Timber Structure Sungnyemun

본 논문에서는 전통 목조건축물로 되어 있는 대한민국의 국보 1호인 숭례문의 구조해석을 수행하고 안전도를 평가하였다. 전통 목조건축의 대부분의 하중을 차지하고 있는 숭례문의 지붕하중을 상세히 산정하고 숭례문의 가구구성 특징을 면밀히 살펴 범용 구조해석 소프트웨어인 midas Gen으로 구조해석모델을 구축하였다. 수직하중에 대한 정적구조해석을 수행하고 주요 수직 수평 구조부재의 안전성과 주요 수평부재의 사용성을 평가하였다. 숭례문의 동적거동특성을 평가하기 위하여 현장에서의 충격해머실험과 구조해석 소프트웨어를 이용한 고유치해석을 수행하고 그 결과를 비교하고 주요모드를 도출하였다. 수직하중에 대한 검토결과 숭례문은 구조적 능력에 여유가 있는 것으로 나타났다.In this research, the structural analysis and safety evaluation for Sungnyemun -No.1 national treasure of Korea- was performed. Roof loads were calculated in detail, and structural analysis model was constructed using Midas Gen ver.820. Static structural analysis under vertical loads was performed and safety of main structural members and serviceability of main horizontal members were evaluated. To evaluate dynamic characteristics of Sungnyemun, both field measurements by impact hammer test and eigenvalue analysis by structural analysis software were performed and the results were compared. Sungnyemun showed rooms in their structural capacity.

Traditional Timber Structures in Extreme Weather Conditions

In addition to seismic events, climate changes—which are reflected in extreme events such as heat and cold waves, storms, floods, landslides, mud-slides and avalanches—can cause irreversible damage to cultural heritage. Although predicting the occurrence of natural and human disasters and their perimeter is not trivial, the increasing impact of extreme events requires critical evaluation of prevention strategies, immediate response and rehabilitation measures. This work aims to discuss the general characteristic features of natural disasters and their impact on cultural heritage focusing on damage to vernacular timber structures in (summer) storms. The study is based on the analysis of damage identified in summer storms in Slovenia in 2008. Possible mitigation and repair strategies are furthermore discussed.

Research on Strengthening Methods of Traditional Timber Structural Dwellings in Shennongjia Region

Chinese traditional timber structure is the most direct embodiment of splendid building culture, it is always known for good structural integrity and good seismic performance. However, due to the influence caused by the timber structure itself and many factors of the outside world, that often make the structure suffering different degree of destruction after using a period of time. In this article, we through the analysis of general form and cause of the destruction, research on strengthening technologies of traditional timber structural dwellings in Shennongjia region, to provide some ideas and thoughts for people who want to renovate and strengthen traditional timber structural dwellings.

Evolution and Composition of the Traditional Timber Structure Column Bases in the Southern Region of China - A Case Study of Shaoxing City

As a very unique structural component of traditional timber architecture, column base is a natural combination of stone carving technology and timber structure system, from which we can understand the broad and profound traditional architectural culture. In This paper, the emergence and evolution of the column bases art history was firstly described to analyze the factors that promote the development and changes of column bases. Moreover, Finally, the dimension of column bases was introduced. The results of this paper can be taken as the reference for the development of the antique buildings and the new Chinese architecture.

Rotation Performance of Javanese Traditional Timber Joint

Many Javanese traditional timber structures have been destroyed by major earthquake. A lot of them tend to be dismantled due to a high cost of reconstruction and a demand for more reliable structures. In order to preserve this disappearing building as valuable and tangible culture, a deeper understanding on these traditional timber structures is necessary. Especially the restoring force of the traditional joints, which are the major earthquake-resisting elements has to be investigated. The static characteristic of these structural components has been investigated experimentally. A total of 12 full-scale specimens of 2 types made from glued Acacia-mangium were tested. The specimen simulated joint at middle part, which is a joint of column-tie beams interlocked each other. The horizontal cyclic load was applied on the specimen placed in pin joint frame from two mutually perpendicular directions. The cyclic loading protocol consists of 7 increasing target deformations from 1/200 radian to 1/15 radian, and finally until failure. As the test result, failures were caused by embedment, crack, and split in beams parallel to the load direction. All crack of beam started from corner of beam mortise and resulted in the split. From the curve of load and rotational relationship, occurrence of initial slip leaded to the larger deformation. It revealed the importance of joint tightness against future earthquake.

Novel Nail-Like Wood Connectors

In traditional timber structures, hardwood connectors such as a nails, wedges, dowels and pegs have been used as reinforcement of carpentry joints or to fix wooden ceiling matts or floor boards. In the study reported, the possibility to rely on enhanced mechanical and technological properties of densified wood, for the production of wooden nails to be used in the repair of traditional timber structures is discussed. The wood used for connectors were domestic wood species; ash, beech, black locust and poplar. Wooden blocks were exposed to densification procedure with the purpose of increasing the materials density, dimensional stability and possibly, improve durability and selected mechanical properties. The densification ratio varied between 50 and 67%. A dedicated research has been performed in order to determine the effect of densification on the compression behavior of wood in the form of nails. The progress of pushing force during insertion of the wooden nails into wood samples was also monitored and served for insertion process control. A preliminary series of push-out tests have been carried out on timber-to-timber joints assembled with the densified nails.The results obtained show potential for using the novel wooden nail connectors for substitution or integration repair works in traditional timber systems.

Structural Performance Analysis and Repair Design of Wenxing Lounge Bridge

Lounge bridges in Taishun are a special type of Chinese traditional timber structure. Wenxing Lounge Bridge is a famous bridge of them. The analysis of structural performance and damages for Wenxing Lounge Bridge is the foundation of its repair and reinforcement. The performance degradation of wood material and the action of strong external force and the effect of environmental changing and the factor of unfavorable human-activity have continuously accelerated the damage of the bridge. After visiting local craftsmen, building technics and detailed conformations of the bridge are researched. The FEM analyses on the structure before damaged and after damaged are carried out respectively. Damages reasons of the bridge are then generally analyzed and repair design of the bridge is also presented.

Use of non-destructive techniques in Chinese traditional timber structures

The study of structural damage detection in ancient Chinese timber buildings is very important in the protection and rehabilitation of the ancient architectural culture. The purpose of structural damage detection is to identify the location and grade of structural damage based on the variation in characteristics of the structure, which is dependent on positioning techniques and quantitative analysis of structural damage detection. These elements are studied thoroughly by introducing microtremor measurements and using the finite-element method. Multi-domain microtremor measurements are performed to detect the tilting and twisting of the structure. From the observational data, the natural frequencies and vibration modes of the structure are evaluated, and these are compared with numerical results. In the numerical analysis, the changes in dynamic characteristics of the structure, such as natural frequencies and natural modes, are obtained, with special attention paid to the characteristics of brackets. Comparing the natural frequencies and natural modes from microtremor measurements with those from three-dimensional numerical analysis, the location and form of the damage is qualitatively delimited. Through continued reduction of the stiffness of the damaged layer in different directions, until the natural frequencies and natural modes from the simulation are shown to be consistent with those of the microtremor measurements, the severity of damage to the structure is quantitatively evaluated.

Testing and modeling of a traditional timber mortise and tenon joint

The structural safety and behaviour of traditional timber structures depends significantly on the performance of their connections. The behaviour of a traditional mortise and tenon timber joint is addressed using physical testing of full-scale specimens. New chestnut wood and old chestnut wood obtained from structural elements belonging to ancient buildings is used. In addition, the performance of different semi and non-destructive techniques for assessing global strength is also evaluated. For this purpose, ultrasonic testing, micro-drilling and surface penetration are considered, and the possibility of their application is discussed based on the application of simple linear regression models. Finally, nonlinear finite element analysis is used to better understand the behaviour observed in the full-scale experiments, in terms of failure mode and ultimate load. The results show that the ultrasonic pulse velocity through the joint provides a reasonable estimate for the effectiveness of the assembly between the rafter and brace and novel linear regressions are proposed. The failure mechanism and load–displacement diagrams observed in the experiments are well captured by the proposed non-linear finite element analysis, and the parameters that affect mostly the ultimate load of the timber joint are the compressive strength of wood perpendicular to the grain and the normal stiffness of the interface elements representing the contact between rafter and brace.

Construction Technology of Centro-Column Drum Towers of Dong Nationality

Abstract: The building structure of a Dong nationality’s drum tower is divided into two categories, namely, the tai-liang and chuan-dou hybrid structures, and the chuan-dou structure, which are from the major carpentry structure system of traditional Chinese timber structure architecture. Then, the most common “centro-column” type drum tower among the chuan-dou structure drum towers is defined and classified. The structure technology features of “single-column” and “ringed-column” drum towers, which are also those of a “centro-column” drum tower, are discussed in great detail. Through surveying and mapping, structure conversion models, such as those that “increased columns” and “reduced columns” of “ringed-column” drum towers, are studied mainly. In addition, many specific construction details that improve a drum tower’s external image, like multi-eaves, columns that are inclined inwards, as well as the honeycomb Dougong, are also studied in this paper.

組物にみる伝統的木造建築の特徴(<メカライフ特集>ニッポンのオンリーワン「メカ」)

組物にみる伝統的木造建築の特徴(<メカライフ特集>ニッポンのオンリーワン「メカ」)

YIELDING MECHANISM OF EMBEDMENT OF WOOD AND FORMULATION OF ELASTO-PLASTIC EMBEDDED DISPLACEMENTS

The restoring force characteristics of embedment of wood are fundamental and very important to evaluate the seismic performances of traditional timber structures. In order to evaluate them effectively, elasto-plastic embedded displacements due to equally loaded rigid plate are formulated by applying Pasternak model to wood members with a finite length, taking the strain hardening and the orthotropic properties into account. In the formulation, the stiffness function is introduced to express the embedment stiffness simply in both elastic and plastic states. Then the formulations are discussed with embedment test results.