Quantitative assessment method of structural safety for complex timber structures with decay diseases. (December 2021)

• Record Type: Journal Article
• Authors: Zhang, Chengwen; Chun, Qing; Lin, Yijie; Han, Yidan; Jia, Xiaohu
• Is Part Of: Journal of building engineering. Volume 44(2021)
• Publication Date: 2021-12
• Subjects: Dou-gong -- Timber structure heritage -- Quantitative evaluation -- Micro-damage detection -- Decay; Building -- Periodicals; 690.05
• DOI: 10.1016/j.jobe.2021.103355
• Languages: English
• ISSNs: 2352-7102

Abstract

Abstract: Decay disease is one of the typical damages in traditional timber buildings. The existing research about the decayed timber focused on the detection and assessment method of a single component. This paper aims to establish a new quantitative assessment method of structure safety for complex timber structures with decay diseases. Therefore, Dou-gong in Southeastern China was chosen as a typical case to specifically clarify the method, which is a typical complex timber structures widely used in China, Japan, South Korea and some other Asian countries. First, based on the field investigation results of some typical Southeastern Chinese timber buildings, eight scaled Dou-gong specimens were designed. Then, the specimens were cultured with wood-rot fungi for 0, 1, 2, and 3 months. Vertical static and horizontal low-cycle tests were carried out to obtain the failure mechanism and the degradation level of the mechanical properties of the Dou-gong specimens at different degrees of decay. Second, the importance ranking of components was calculated based on the energy method to simplify the selection of decay detection points. Then, two complementary micro-damage detection methods were used to detect the degrees of decay of the Dou-gong specimens. Finally, based on the test and detection results, the relationships between the decay degree of the Dou-gong and the degradation amplitude of the vertical bearing capacity, the horizontal bearing capacity, and the hysteretic curve envelope area were established. The research results show that the decay detection priorities of Hua-gong, Upper Xia-ang, Lower Xia-ang, Nidao-gong are high, and the decay degree of these four members can generally represent the decay degree of the whole Dou-gong. A mathematical expression from the sigmoid function family can be used to fit the relationship between the degree of decay and the mechanical properties of the Dou-gong. The results can provide a scientific basis for quantitative assessment method of structure safety and conservation of complex timber structures with decay diseases. Highlights: Getting the mechanical properties of decayed Dou-gong cultured with wood-rot fungi. Determining the decay detection points based on the energy method scientifically. Establishing a new relationship between decay degree and mechanical property. Building a quantitative assessment method for decayed complex timber structures.