Structural Behavior Of Column-frame Joints In Yingxian Wood Pagoda

Yingxian Wood Pagoda which was built in 1056 AD during the Liao Dynasty is the highest and oldest standing ancient storeyed wood structure in China. It is located in Fogong Monastery in Ying County, Shanxi Province. As an important cultural treasure, it represents the outstanding achievements made by ancient Chinese people in architecture. Due to natural and human-induced disasters,Yingxian Wood Pagoda is badly damaged and is in urgent need of reparing. Joints are the most significant aspect of wood structures. It is needed to investigate the structural performance of the column-frame joints that were used to construct the pagoda. Column-frame in the Yingxian Wood Pagoda was connected by tenon and mortise joints which are typically semi-rigid. Two types of column-frame joints are identified in Yingxian Wood Pagoda, the beam-column joint between beam and horizontal components like Lan-E and Pu-Pai-Fang, and the column-base joint between the bottom-end of column and components of the supporting Dou-Gong, which is also traditionally termed"Chazhuzao". Formation of column-frame joint varies with the location of the column. In this study, the structural behavior of column-frame joints was investigated. Four joint models with a ratio of 1/3.4 to the prototype, were manufactured according to the prototype of column-frame joints in the second apparent storey of Yingxian Wood Pagoda, and were tested under low cyclic lateral load. Failure modes, the hysteretic curves and the skeleton curves were obtained from the experiment. In addition, comprehensive material tests of the Northeast China red pine used to manufacture the models were conducted to determine the elastic constants, strengths and friction coefficients. The test results can be used in simulation of the experiment, and can also be a reference of similar test.3-D FE models of the joints for experiment were developed using ABAQUS. The structural behaviour was simulated using quasi-static method. The FE modeling results correlate closely with the experimental results, proving that the FE models are valid and reliable. Based on the experimental and simulation results, 3-D FE models of the prototype column-frame joints of Yingxian Wood Pagoda were developed and simulated in order to investigate the structural behavior of the joints. From the FE modeling results, equations for the Moment-rotation relationship of each joint were given to predict the lateral resistance behavior under different vertical load levels. Restoring force models of each joint were established based on the Clough bilinear hysteretic model.The failure modes were classified and some ideas were given for strengthening and reparing of the pagoda.