| As inheritance carrier of Chinese ancient history,ancient tower combines Chinese and foreign cultural essence,which brings pretty high value of humanities and arts and architectural science to the world.The existing ancient tower not only has the humanistic value of art appreciation,scientific research value is higher.After suffering long periods of natural disaster,war and being damaged by human,the existing ancient tower is troubled by lots of problems as material aging damage of structure and strength reducing.Especially,with the material condition is greatly improved,the existing ancient tower,as art treasures,protection of which has become a main part of the protection of ancient buildings in our country at present.Research on the existing ancient tower in seismic zone is still in the initial stage of research and analysis in China,and the number of the tower,which can be further researched is relatively scarce.Limited by research conditions and other reasons,there has no detailed protection measures.By searching and reading a large number of literature and analyzing and investigating,this paper focuses on research of shock absorber design and measures by using the method of combination of experimental and theoretical analysis.The priority of this article are as follows:(1)The current status of small wild goose pagoda in Xi’an is investigated and analyzed,and modeling the prototype structure of small wild goose pagoda by the large-scale finite element analysis software ANSYS.Analysis of the dynamic characteristics of the small wild goose pagoda structure is conducted,and the results can accord with the numerical small wild goose pagoda dynamic test,which can reflect the dynamic response of small wild goose pagoda structure.On the basis of results above,Model seismic response analysis has been made by using time history analysis method,which shows the response of the small wild goose pagoda in 8 degree seismic displacement,the acceleration and internal force.Results show that the small wild goose pagoda structure can basically meet the anti-seismic requirements of small earthquakes in 8 degrees,in the mid earthquakes of 8 degree,part of the structure,especially the upper part,appears moderate to severe damage;in the big earthquakes of 8 degree,the displacement response of the structure is relative large,and most of the structure is close to the collapse limit value,which shows that the structure appears damage,and it is difficult to guarantee the safety of the 8 degree big earthquakes.(2)According to the small wild goose pagoda prototype,a similar ratio of 1/10 test model structure of the small wild goose pagoda is designed and made.Meanwhile,according to the main characteristics of the small wild goose pagoda protection,without prejudice the appearance of the small wild goose pagoda and historical information and easy to be integrated Shape Memory Alloy-Suspension Pendulum Damping System(SMA-SPDS)is designed and made.At the same time,it is installed at the key point of the structure.On the basis of that,finite element model is established,and seismic response time history results under non-controlled and controlled structure and various working conditions is analyzed.The small wild goose pagoda model structure non-controlled and controlled modal characteristics,the top area displacement and acceleration response etc is also researched,and the corresponding comparative analysis is carried out.Moreover,damping effect of changing number of SMA-SPDS.The results show that the structure integrated SMA-SPDS changes a lot on model characteristics,the top area displacement and acceleration is reduced effectively,and damping effect is more obvious with more SMA-SPDS.(3)According to the main characteristics of our existing masonry pagodas,combined with the basic principles of the conservation of historic buildings,this paper researches on reducing the masonry pagoda structure seismic response of basic theory and seismic design method,and analyzes damping system working principle and construction method which is convenient and suitable for the protection of ancient pagoda.In addition with the actual situation of small wild goose pagoda and the main features of SMA-SPDS,position arrangement and quantity of the calculation method of SMA-SPDS in the small wild goose pagoda structure is proposed,and referring to the relevant research results,and putting forward the simplified calculation method of the number of SMA-SPDS.The research results can be used not only to provide theoretical and technical support for earthquake protection of small wild goose pagoda,but also could provide a reference for earthquake protection of the ancient masonry pagoda structure. |
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