Research On Seismic Performance And Damage Assessment Of Multi-layer Wooden Structures Of Ancient Buildings

Xian Ming city wall Yongning Gate(South Gate) gate, formerly the Sui and Tang Dynasties imperial city of Changan and the late Tang Han Anshang gate, At the end of the Tang Dynasty to the Northern Song Dynasty closed the door, away, to the Qing Dynasty city wall is only open the door on the South.The gate was built in seven to eleven years of Hongwu of the Ming Dynasty, the eternal peace of righteousness, including the tower, Embrasure watchtower, gate watchtower, Weng Cheng City, on the city, as an important gateway to the south of Xi’an government. In 1926 the town was burned Liu Zhenhua song army, now in order to restore the integrity of Xi’an city wall shape, and its watchtower conduct rehabilitation, and based on modern seismic norms between seismic performance, structural damage and hysteretic energy for its internal mechanism research.In this paper, the Xi’an city wall Yongning gate reconstruction project as the background, according to "Qing structure regulations",the production a 1:6 scale model of straight mortise column frame, save the brackets model and column model, as well as the watchtower structure in the central three wooden frame model,through the quasi-static test and shaking table the experiment, analysis of the three component model in fitting the stress state and failure characteristics under static load;Through the observation of the shaking table test and analysis of structural damage, the change trend of the displacement and acceleration responses of the model structure in different earthquake conditions;According to the structure of the interlayer shear force and displacement hysteresis curve of the structure of the parts or absorb the dissipation of energy, so as to establish the corresponding relationship between structural damage and hysteretic energy dissipation. And reached the following conclusions:(1)The static analysis of experimental phenomenon and damage of components characteristics of the straight tenon column frame, save brackets shop and column component scale model, the main form of wooden structure of ancient buildings damaged in the earthquake component.(2)Based on the scale of the Yongning gate(1:6 gate) seismic simulation shaking table model test data analysis of the watchtower, the ancient wooden structure building in the structural dynamic characteristics and seismic response characteristics under the different seismic excitation, results show that, with the increase of earthquake excitation, the energy dissipation capacity of the structure increases, the most obvious energy dissipation effect of column frame layer.(3)In order to grasp the Yongning gate(South Gate) failure process and state of the watchtower under seismic action, to make a reasonable assessment of the extent of damage after the earthquake, the column frame tenon and mortise tenon mortise joint, Dougong structure layer and the base layer under low cycle horizontal cyclic loading hysteretic behavior and the energy dissipation based on the principle, the column frame straight tenon mortise tenon joints, Dougong structure layer and the base layer as the three main energy component failure, total energy calculation in different seismic conditions the energy component "component"; Based on the "total energy component damage" components and each component failure model established major energy components under different conditions in the earthquake earthquake energy situation; The introduction of the energy distribution coefficients established major energy component to the overall structural damage destroy state relations between states, and then come to destroy the whole structure of coefficients to reflect the state of the overall structural damage under different earthquake, the results can be multi-layered structure of ancient wooden buildings provide seismic strengthening scientific and rational theory.