Analysis On Seismic Performance Of Monolithic Moving Pagoda

The contradiction between protection and demolition of building occurs in the process of urban renewal,road widening and river governance with the rapid development of economy and the ongoing urban construction of our country in recent years.The historical and cultural value of the pagoda and other buildings is invaluable,demolition of them will cause enormous losses.Building translation makes these buildings avoid removal and complete retain the original historical appearance with good social benefits.Based on the first domestic monolithic movement project of ancient pagoda as the background,the finite element software is used to study seismic performance of the pagoda before and after the translation and analyze linking method of the translation and mechanical property of the underpinning structure.It is shown that the main structure of the pagoda before translation is intact,there are minor cracks at the bottom of the first floor.Because of the underpinning structure,the natural vibration period of the pagoda after translation becomes longer and the response of seismic action becomes more intense.The analysis of the seismic performance of the ancient pagoda after translation should consider the effect of underpinning structure.The maximum story drift angle which appears at the top of the pagoda after translation dose not exceed story drift angle limitation under frequent earthquake action so that the main structure is in good condition.The maximum story drift angle of the pagoda after translation under rare earthquake action is 1/76,more than 1/260,the top of the pagoda is severely damaged and the upper parts of the tower body are moderate damaged.The stress of the pagoda after translation is larger than before translation and the stress of the underpinning structure is small.The bottom of the first floor of the pagoda is easier to crack under earthquake action.The results show that the bottom of the pagoda is the weak part of the structure that it should be paid more attention to reinforcement and maintenance of the bottom.The dynamic characteristics and the seismic response of the pagoda after translation with earthquake isolation is analyzed in this paper.The natural vibration period of the pagoda increases by 2.54 times after setting isolation bearings.The displacement and acceleration of the vertex under frequent earthquake action decrease by an average of 56.8% and 57.6% respectively and under rare earthquake action theyare by an average reduction of 88.7% and 77.6%.rarely occurred between seismic accelerations lower layer between displacement and 38.9%,respectively,and 53.6%lower than the upper part of the tower seismic reinforcement,both significantly reduce the seismic response of the tower,but also to protect the integrity of historical relics tower style,easy to set,economy good for heritage buildings tower displacement.FEM analysis is carried out to study the stress and deformation of the underpinning structure.The maximum deflection of prestressed underpinning beam and non-prestressed underpinning beam are both less than the deflection limitation of flexural member in the code.The stiffness of the underpinning structure is satisfied the engineering requirement and the tensile stress and compressive stress of the underpinning structure does not exceed the ultimate strength of materials,the underpinning structure satisfies the requirement of strength.