This study analyzed displacement records of Sungnyemun Gate's primary structural members, such as columns, beams, and hip rafters, over approximately ten years from 2013 to 2023. Through this, we attempted to examine the behavior of wooden architectural heritage in detail and infer the factors influencing structural change through the deformation revealed during the displacement accumulation process. As a result of the analysis, it was quantitatively confirmed that the prominent structural members of the Sungnyemun gate, including the columns, beams, and hip rafters, continued to move and that the accumulated displacements from the movement led to the structure's deformation. It was also confirmed that member displacements accumulate in a specific direction. In the case of the Sungnyemun gate, even after the structure was stabilized, the columns were tilting inward toward the building, and the ends of the hip rafters and the centers of the beams were moving downward continuously. Furthermore, the behavior of wooden architectural heritage, in which damage accumulates as it undergoes repeated transformation and recovery according to seasonal changes, was also revealed in detail. The deformation of the Sungnyemun gate members shows a common pattern of relatively large behavior in the summer. However, seasonal deformation did not appear the same in all members. Even the same member has an uneven drying speed due to differences in the amount of sunlight received depending on the location, leading to uneven distribution of deformation. This study, while acknowledging its limitations, is significant in that it attempts to examine the behavior of our wooden architectural heritage in detail and discuss its characteristics and influencing factors based on quantitative results of long-term measurements.

This study aims to examine the cutting traces remaining on the bracket tie beams of Sungnyemun gate, identifying the tools employed during the late Goryeo to early Joseon periods by specific processes, and deliberating on the timber shaping techniques utilized in advanced architectural construction during the late Goryeo to early Joseon eras. Through the research, it was confirmed that in the production of Sungnyemun Gate's bracket tie beams during the 14th to 15th centuries, both the timber splitting and ripsawing methods were used in conjunction. Moreover, the wood finishing process revealed the use of a plane. It can be inferred that the characteristics of the plane used during that time were not significantly different from those observed in the later period of the Joseon dynasty. The ripsawing and plane finishing techniques were evident in various parts of the bracket tie beams of Sungnyemun gate across the reigns of king Taejo and Sejong, indicating that the techniques involving ripsaw and plane were already prevalent in the late Goryeo period. Consequently, it can be inferred that the ripsawing and plane finishing techniques might have been applied in the construction of prominent government buildings in Hanyang(Seoul), including Gyeongbokgung Palace, and in the residences of royalty and nobility after the establishment of the Joseon dynasty.