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.