Influence Of Shock Absorber On Seismic Performance Of Existing Reinforced Concrete Single-span Frame Structures

Due to the limitation of construction funds and the national demand for green buildings,some old buildings in many parts of our country can not be demolished,but need to be strengthened and transformed through effective measures.At present,there are many school buildings built in the 1990 s in Yunnan Province.These buildings are usually reinforced concrete frame structures,and a considerable part of them are single-span frame structures.In recent years,the situation of earthquake disasters shows that this kind of structure is prone to collapse under the action of earthquake,and the damage of earthquake is very serious.In addition,after the 2008 Wenchuan earthquake,the state also raised the seismic fortification target of buildings.How to improve the safety of the existing single-span frame structure is a problem worthy of consideration by the majority of scientific researchers.There are two kinds of reinforcement methods for buildings: Direct-reinforcement and Indirect-reinforcement.Among them,The methods of indirect reinforcement are as follows: adding components,adding shear walls and adding energy dissipation shock absorbers.In recent years,the method of using energy dissipation for seismic strengthening has become a new direction for the development of seismic strengthening of existing buildings,and the use of dampers for seismic strengthening has been widely concerned at home and abroad.In this paper,the reinforcement of a primary school building in Yuxi is taken as an engineering case,which is an existing single-span reinforced concrete frame structure.In this paper,the finite element simulation method is used to study the energy dissipation structures based on energy dissipation buckling-restrained braces and viscous dampers respectively.(1)This paper reviews and summarizes the reinforcement theory and research status of reinforced concrete structures,and briefly introduces the concept,structure and related theory of buckling-restrained brace(BRB)and viscous fluid damper(VFD),as well as their research and engineering application status.(2)According to the test results of the existing reinforced concrete frame structure,YJK is used to establish the model of the existing reinforced concrete frame structure.Through the analysis of the original structure,two schemes of BRB reinforcement and VFD reinforcement are proposed,and the two reinforcement schemes are compared and analyzed.(3)Using SAP2000 finite element software,the model of BRB seismic strengthening is established.On the basis of verifying the correctness of the model,seven reasonable seismic waves are selected to carry out elastic time-history analysis under frequent earthquakes and elastic-plastic time-history analysis under rare earthquakes,and the seismic response of BRB seismic strengthening model is obtained.Check whether the seismic performance index of BRB reinforcement model meets the requirements of relevant specifications and technical regulations.(4)Using SAP2000 finite element software,the VFD seismic strengthening model is established.On the basis of verifying the correctness of the model,seven reasonable seismic waves are selected to carry out the elastic time-history analysis under frequent earthquakes and the elastic-plastic time-history analysis under rare earthquakes,and the seismic response of the VFD seismic strengthening model is obtained.Check whether the seismic performance index of VFD reinforcement model meets the requirements of relevant specifications and technical regulations.(5)Through the comparative analysis,the BRB dampers are finally determined to be used for the reinforcement of the single-span reinforced concrete frame structure,and the location of BRB and the corresponding design parameters are also given.(6)Finally,the research work of this paper is summarized,and the suggestions for further research are put forward for the existing single-span reinforced concrete frame structure.