Research On Seismic Damage Feature Of Longhu Pagoda In Wenchuan Earthquake

Masonry pagodas are the deputies of the ancient tall buildings and the important historical cultural heritage. Existent masonry pagodas were built a long time ago. They have encountered all sorts of damage of human and natural calamities, and the material properity has changed a lot. Masonry pagodas are vulnerable to earthquake, due to brick masonry material and construction characteristics. With the help of simulation technology, seismic response of the typical ancient pagoda is analyzed.The damage pattern is deduced and the damage feature is summarized. They provide the evidence for seismic strengthening and restoration. They have theoretical and applied value. Taking Longhu Pagoda as the research sample, this paper researches on seismic response and damage feature of Longhu Pagoda by theoretical analysis and site measurement and numerical simulation. The main contents include:(1) The initial model of the dynamic behaviors by spatial finite element method generally reflects actural construction of Longhu Pagoda. By means of the senstive response analysis on the dynamic behaviors, this paper proposes generalized modulus and considers the influence of the cornice of pagoda, interior details, material properties, the damaged condition and reinforcement, modify the stiffness of model compared with the experimental result on the frequency and vibration. Establish a model by parameters fitting on the dynamic behaviors of masonry pagoda.(2) Accoding to seismographic record of seismostation of Shifang star, time history curve and response spectrum curve of three coordinate direction are analyzed. The dynamic response of masonry pagoda in earthquake is analyzed by time history analysis with the help of numerical simulation. Taking displacement and shear stress as assessment criteria, search the weakness of Longhu Pagoda.(3) By means of ANSYS/LS-DYNA, the seismic damage evolution process of the fifth floor and vertical axle wire of Longhu Pagoda in Wenchuan Earthquake is simulated by defining nonlinear elements in the nonlinear seismic analysis.The research result of this paper is an important contribution to reveal seismic damage mechanism. However, it is hard that material properties, interior details and the damaged condition of masonry pagoda are accurately described, due to the limitations of hardware and software. It needs more explorations.