Research On Seismic Protection Of Masonry Pagodas

Masonry pagodas are deputies of ancient high-rise buildings which are elites of foreign culture and china traditional architectural art. Most ancient pagodas are lie in the frequency region of earthquakes. Some ancient pagodas which its earthquake resistant behavior is weak for most pagodas have internality weakness and are weather-beaten. Many ancient pagodas' destroy or collapse is for the earthquakes. aftertime pagodas will still be faced with the earthquake destruct threaten .These ancient pagodas must be the beyond recall loss once earthquake takes place .As a result ,the research on seismic protection of masonry ancient pagodas is no time to delay.Based on extensive investigation of construction technique history of Chinese ancient buildings, the structure origin, the structure developing history and structure characteristic of Masonry ancient pagodas are discussed, and its seismic behavior is analyzed. Take example for the big goose pagodas, Using FEM software, the dynamic properties and the flexibility time history of masonry ancient pagodas are analyzed. Such work has been done as follows:1. The origin, developing, evolvement history process, contexture and construction of masonry ancient pagodas existing have been analyzed.2. Based on the textual research of history data and earthquake damage investigation, the earthquake resistant mechanism has been analyzed, the connection with earthquake damage phenomenon and structure characteristic of many style masonry ancient pagodas.3. Take example for the big goose pagodas, dynamic properties of masonry pagodas and its influence factor have been analyzed; result indicates that the dynamic properties of masonry pagodas are influenced most by elasticity modulus. On the condition of not locale measuring the dynamic properties of masonry pagodas, using three-dimension entity finite element model simulating the dynamic properties of masonry pagodas is reasonable. Based on the analysis of a few masonry pagodas' natural period of vibration, practicality formula of estimating themasonry pagodas' natural period of vibration is summarized.4. Using FEM software ANSYS, time history analysis of big goose pagodas has been studied by inputting five different seismic waves. Structural displacement response has been gained. Result indicates: Structural displacement response is largest as inputting Tianjin seismic waves, for its characteristic period is closed to the natural period of vibration of the model. The results of by inputting several different seismic waves indicated that displacement response of the pagodas' upside (top, top of seven floor, top of six floor) is larger. Thereby, it also explained in theory that the primary earthquake damage characteristic of masonry pagodas in earthquakes is that vibrated dropping of the pagoda's top and vibrated collapse of the pagoda's upper parts.