The deterioration state and degradation mechanism of historical timber structures from the Yunnan Military Academy

ABSTRACT

Wood structural timbers at three locations (eave, beam frame, and column) were exploited to elucidate the deterioration state and mechanism of historical timber structures from the Yunnan Military Academy (Kunming, Yunnan Province). The morphological structures, physical and mechanical characteristics, and chemical components were measured to illustrate the deterioration state and elucidate the degradation mechanism. The results demonstrated that the deterioration of structural timbers was closely dependent on their locations in the architecture. The outside eave was in the worst deterioration state, which was caused by natural factors (ultraviolet rays, rain, and fungi), resulting in severe distortion of wood structures and a significant reduction in basic density and compressive strength. Significant carbohydrate losses that occurred in the eave and beam frame were mainly contributed by the brown rot fungi, predominantly due to the frequently wet condition and humid environment. Moreover, column structures were mainly attacked by insects (weevils) due to their location near the ground, accordingly in an obvious decline in mechanical properties. Collectively, structural timbers exhibited different deterioration states contributed by the degradation mechanism, predominantly influenced by their locations in architecture.

GRAPHICAL ABSTRACT

KEYWORDS:

• Historical timber structures
• degradation
• morphology
• physical and mechanical characteristics
• chemical characteristic

Acknowledgements

Author contributions: Conceptualization, G.D., B.Z.Z. and J.Q.; formal analysis, G.D. and H.Y.; investigation, G.D. and Y.Z.; writing—original draft preparation, G.D.; writing—review and editing, G.D. and Y.X. B.L. and S.D.D.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors are grateful for the financial support by the Regional Project of National Natural Science Foundation of China (31860186, 32260362, 31360157), the Joint project of Yunnan Agricultural Basic Research (202101BD070001-058), and the 111 Project (D21027).