Nondestructive assessment of wood structural members at Yu Tomb of the Ming Dynasty, Beijing.

Yu Tomb of the Ming Dynasty in Beijing is the tomb of Zhu Qizhen, who was the 6th emperor in Ming Dynasty. Yu Tomb was built up in 1464, and did not get any maintenance from 1911. After 100 years, some constructions on the ground have gone, and residual constructions, such as Ming Lou, were damaged severely. With the financial support from Beijing government, the constructions on the ground of Yu Tomb begun to reconstruct from 2011. Wood members of beam and column of the residual constructions need to inspect and evaluate one by one, in order to reuse these wood members as more as possible. Authors took responsibility of the nondestructive testing and evaluations of wood members. Wood members on the Ming Lou were taken down first, then inspected and evaluated, and wood members on the Three Gates and Holy Beam were inspected and evaluated on the structures. Species of the wood members were identified first, and then defects of 62 beam and columns were inspected and evaluated with visual inspection, stress wave and resistograph. It was found that all wood members had defects of decay or crack, in which 41 wood members got serious defects, which could not be repaired; and 21 wood members got minor defects, which could be repaired and reused. The results of inspection and evaluation gave architects and construction engineers a big help with quantitative data of defects.