A static test was conducted to investigate the elastic and post-yielding structural behaviour of complex brackets system along the corridor frame region of the Taiwanese Dieh-Dou timber structures. One partial fully scaled specimen was loaded horizontally under different vertical loading levels. A mechanical model, focusing mainly on the rotational behaviours of bearing blocks and timber interlocking joints, was developed to estimate the global behaviour of complex brackets of the Dieh-Dou corridor frame region. By assuming each spring stiffness to behave bi-linearly, the model is only valid for the estimation of the primary and secondary stiffnesses. The force–deformation relationship is highly dependent on the rotational spring stiffness and vertical loads. Hence, when a heavier vertical load is imposed onto the structure, yielding rotation increases and subsequently, the yielding moment of the bearing block members is improved further. Generally, the predicted model was in good agreement with the observed results, up to the post-yielding loading level.
19 March 2018 in International Journal of Architectural Heritage
Under different combinations of horizontal and vertical loads, a total of three quasi-static cyclic tests were conducted to investigate the structural behavior of the Dieh-Dou timber frame. Typical deformation patterns include column rocking, joint rotation around the primary beam-column and column Dou-column regions, vertical shear around the column mortise, embedment around primary beam-column regions, and vertical shearing around the mortise regions of the Dou members. Visible deformation generally began from 1/30 rad onward. The column-restoring force contributed mainly to the frame’s moment resistance when displacement is small. When frame deformation exceeds 1/50 rad, bending moment from the primary beam dominated the global restoring force. Hence, the column-restoring force and the primary beam-column connection generally undertake the primary moment-resisting mechanism while the complex bracket structures above the primary beam play a secondary role. Based on the embedment theory and semi-rigid spring concept, a new theoretical model was developed to estimate the global behavior of the Dieh-Dou main frame. Although the prediction tends to be on the conservative side, the predicted model is generally in good agreement with the observed results.
9 April 2015 in International Journal of Architectural Heritage
This article attempts to explore the dynamic behavior of traditional Dieh-Dou timber structure under different combinations of structural forms and vertical loads. Using time-history record (TCU 084) from the Chi-Chi earthquake, two semi full-scale specimens (Symmetric and Asymmetric) were tested. Results showed that the Symmetric specimen tends to be damaged more easily and faster than the Asymmetric one. Damage pattern generally begins from the bottom Dou members and subsequently spreading upwards to the upper Dou, horizontal Gong members, and adjoining Shu members. Friction force between the contact surfaces is crucial towards the maintenance of overall structure. Increase vertical loadings have significant effect on the natural frequencies and global stiffness of the structure. Using the Single-Degree-Of-Freedom (SDOF) system, the derived stiffness is generally in good agreement with the dynamic results of both forms. This study suggests that the effects of increasing vertical loadings should be taken into consideration for future evaluation.
In order to understand the painting materials and profile structures used in the creation of Chinese ancient folk architectural paintings, the architectural paintings of the Bell and Drum Tower at Fushan Temple in Shaanxi Province of China was investigated. In this study, optical microscopy, Fourier transform infrared spectroscopy (FTIR), micro-Raman spectroscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), and chemical experimental methods were used. The profile structures, and the elemental and chemical compositions of the pigments and binders in the ground layer of the 12 samples were determined. Results showed that the painting profile structures in both towers comprised of pigment layer, underpainting layer and ground layer, where no starch was found in the chalk ground layer. The pigment layer mainly comprised of iron oxide red, chalk, lapis lazuli, carbon black, green earth, and a dark green pigment that is formed by a combination of carbon black and green earth. To-date, the use of green earth pigment in Chinese architectural paintings was not found in Chinese related academic literature; hence, this study marked the first identification of green earth being used in the architectural paintings. Tung oil, commonly used in Chinese architectural paintings as a binder for pigment, was also identified in the samples. Results from this study will serve as an important reference for better scientific investigation methods on ancient Chinese folk painting materials.
1 February 2021 in Proceedings of the Institution of Civil Engineers - Engineering History and Heritage
The Taiwanese Dieh-Dou-type complex brackets used in traditional timber buildings are commonly believed to sustain both in-plane and out-of-plane loadings of the main frame during seismic events. From past statistical investigation, single-tier, double-tier and triple-tier asymmetric bracket designs were chosen as test subjects. A series of quasi-static cyclic tests was applied to full-scale specimens to evaluate their seismic behaviour when subjected to out-of-plane loading. The test specimens generally exhibited significantly higher resistance when all horizontal members sustained compression. The Gong members functioned like braces and subsequently led to enhanced resistance. However, when the global structure was subjected to tension, the joints of Gong, purlin support and purlin members were more likely to be pulled out. The counter-resistance force observed from the tension side resembled that of rigid-body rotation. The triple-tier specimen sustained more serious damage than the other two types, where the middle Dou member was more prone to split due to stress concentration. The proposed bi-linear semi-rigid spring models were in good agreement with the test results, so the general assumptions made were valid.
4 August 2024 in International Journal of Architectural Heritage