Large Chassis Underpinning Isolation Of Existing Gap Frame Structure Research On Seismic Isolation Retrofit Technology

With the good seismic performance of new isolated buildings in the actual earthquake,the isolation technology has attracted more and more attention,and the isolation technology is rising day by day in our country.At present,there are a large number of buildings which do not conform to the seismic code in our country.it is very uneconomical to dismantle them all,so it is necessary to strengthen and reconstruct the buildings.With the development of seismic isolation technology,the common seismic reinforcement cost is high,the construction period is long,and the construction waste is more and more obvious.seismic isolation reinforcement technology is also gradually beginning to be applied in the existing building reinforcement.With the process of urbanization and the increasing demand for building functions,some buildings with comprehensive use function and long shape also appear in the city.in general,these buildings are provided with expansion joints,settlement joints or seismic joints according to the requirements of the specification,which is called the slotted building in this paper.In a large number of buildings that do not conform to the seismic code,there are a lot of existing buildings that do not conform to the seismic code.these slotted buildings are divided into several parts,and the spacing between the parts is very close.if the traditional isolation and reinforcement method is used to isolate and reinforce each part separately,the horizontal displacement of each isolated and strengthened building will increase under the action of seismic force,and the displacement will cause the risk of collision of each part of the building.therefore,a better reinforcement and reconstruction method needs to be found.Therefore,it is of great significance to study the reinforcement and reconstruction technology of existing slotted buildings.This paper mainly completes the following work:On the basis of reviewing a large amount of literature,this paper analyzes the seismic strengthening technology and seismic isolation reinforcement technology respectively.Through comparative analysis,it is concluded that seismic isolation reinforcement has obvious advantages in seismic performance,strengthening cost,construction period and reinforcement method.It provides the theoretical foundation for the practical engineering reinforcement and reconstruction in the future.This paper makes an analysis and research on the construction technology of existing building isolation and reinforcement,and gives a detailed summary of the construction process and main construction process.two main difficulties in the construction method and the construction method of vibration isolation support are studied in this paper.In order to solve the shortcomings of the traditional installation of isolation mount,a new method for the installation of preload device is put forward.It is of great significance to the construction method of actual engineering and it has important supplementary function to the existing construction technology.When the existing joint frame structure is reinforced by isolated vibration isolation,the reserved slit does not meet the seismic reinforcement requirements.It is proposed creatively that the bottom of each part of the structure is connected,and the isolation layer of a large chassis is made.The base isolation technique is adopted for the existing joint building with a joint at the bottom.According to the actual project,and using the finite element software Midas/gen to establish the seismic isolation reinforcement model,numerical simulation is used to study the seismic performance of each part of the structure.Analyze and calculate the mechanical properties of the building after isolation and reinforcement.Modal analysis and time analysis are carried out for the structures before and after the seismic isolation,It is concluded that the period of the building is significantly increased,the acceleration and the displacement between the layers are obviously decreased.The seismic response of the superstructure is decreased,and the seismic response of the structure is obviously decreased.this is of great theoretical significance for the reconstruction project of building isolation reinforcement in the future.