Application And Anti-seismic Research On The Technology Of Adding Steel And Concrete Composite Storeys On The Top Of Concrete Frame Stucture

The development of China’s economic is relatively slow before reform andopening up, and people also have not very high demand for housing. At that time,most of the residential houses were low-rise or multi-storey buildings. Since theurban population is increasing gradually in recent years, the existing buildings havebeen unable to meet the requirement of social development both in building numberand building usability. But a large portion of buildings still have a lot of use value,demolition or reconstruction will bring about a lot of waste. Therefore, taking theeconomy, applicability of existing buildings, seismic strengthening reinforcementand other factors into consideration, increasing certain additional layer on existingbuildings if they are suitable is a good reinforcement and reconstruction methodwhich can be economical, efficient and relieve the current contradiction betweensupply and demand.Some problems more or less existed in current structure systems used in layeradding transformation, especially the steel structure adding layers lack specificationand standard, which lead to uncertainty performance changes for adding layers.Researches and applications in practical engineering show that layer adding withsteel structure has a better performance compared with the performance of concretelayer adding. During the steel layer adding, composite structure is better inimproving the forces of the lower layer structure due to adding layer and theperformance of the overall structure. Therefore, in the background of a practicalproject, the characteristics of composite structure adding layers on the top ofexisting concrete frame are analyzed and summarized by finite element analysissoftware. Besides, the influences of different add layer parameters on the overallstructure are also analyzed. The research work mainly includes the followingcontents:（1）Because steel structure has many advantages, it is widely applied inreinforcement and reconstruction engineering. But steel structure adding layers also bring about some problems. Through the analysis of present situation and thecharacteristic of steel and concrete composite structure, this paper uses compositestructure adding storey on top of the concrete frame.（2）This paper analyzes the present seismic analysis methods. Consideringobviously different quality and stiffness of two structure parts, the vibration modedecomposition response spectrum method and Pushover analysis method are used toanalyze seismic performance of structures.（3）The seismic response of the structures of different adding factors isanalyzed with vibration mode decomposition response spectrum method. Accordingto analysis results, the force and displacement of concrete frame before and afterreinforcement and reconstruction is compared, and relevant laws are summarized.（4）The design and construction of adding layer’s column foot and support areanalyzed. Besides, the reasonable form of connection method and support for addinglayer is discussed.