Analysis Of Interaction Between The Storey-adding Structure Of Light-weight Steel And The Original Buildings

Most of the urban residential and other civil buildings built before were low-rise or multi-storey. It is not economic to push down those buildings but to expand area is the urgent need; even most of these buildings are not earthquake-resistant qualified or don't satisfy the seismic fortification criteria. So it is important to convert this building.The technique of adding stories with light-weight steel structures is gradually promoted to be a new type of structural reinforcement for its advantages of light weight, good earthquake-resistant performance and easy construction. Also, it is superior to concrete structure in aspects on technology, economy and safety, therefore this technique is widely used in China. However, the design method is not mature yet, mostly, only the load bearing capacity of adding part is considered. But, significant differences of the whole mass, stiffness, period and damping occur when adding light-weight steel structure on the original building. Therefore, it is no longer suitable of just calculating the adding part, and the analysis of the entire structure ought to be carried out.On basis of the form, case study and the present situation of research on the direct storey-addition of the light-weight steel structure and the feature of structure added by light-weight steel storey, this paper has made the static and dynamic analysis on the integral structure includes adding one or two stories light-weight steel frame on three storey, and four-storey by finite element analysis software ANSYS. The data of distortion, displacement etc. are analyzed in fore and after on added storey frame. The results show that the lower frame structure after adding light-weight steel stories, the variation of the stress and strain is obvious in the storey of adding, so it is a vulnerable one and it should be checked by the designer. When add more stories, the effect of high-order mode should be considered. In addition, it gets the rule of force and displacement about storey-adding of light-weight steel structure, and it offers theoretical reference on the design of adding storey for designer. Some critical technique in the practical application to light-weigh steel adding-storey structure is generalized, and the application of light-material and the construction feature of the connection with new structure are put forward from application technology. Then the design of connection area and reinforcement of the original structure are suggested.