Seismic Performance Analysis Of FRP-steel Sleeve Chimney Under Horizontal Seismic Action

Chimney(a high-rise structure with low rigidity)is one of the important engineering structures in Chinese industrial buildings,and it is sensitive to the earthquake.To ensure its safety and reliability on service performance,it's essential to conduct the seismic response analysis of the chimney.Glass fiber reinforced composite materials(commonly known as FRP)is gradually applied in the chimney structure owing to the both good physical and chemical properties,such as light weight,high strength,corrosion resistance and anisotropy.Since code for design of chimneys doesn't covered seismic calculation and design of this new type of chimney structural—FRP-Steel sleeve chimney,this paper has analyzed the seismic response of this new chimney structure under horizontal seismic action,which is of great significance to the seismic design of as well as promoting the application of FRP chimney structure.The main works are as follows.(1)For the FRP-steel sleeve chimney structure,this paper has considered the actual constraints between the inner and outer cylinders,and established the overall finite element model of the chimney structure.The modal analysis,horizontal seismic response spectrum analysis,the horizontal seismic elastic time-history analysis of the chimney finite element model and dynamic response characteristics are carried out,according to the ASME standard,this paper has also checked its strength of the inner cylinder by applying the Tsai-Wu intensity ratio theory.It has found that the results between the time-history analysis and the response spectrum analysis are relatively close,indicating the reliability of the calculation method.The mechanical response of the chimney structure under the action of vertical earthquakes and horizontal earthquakes is analyzed,the results show that the horizontal earthquake has a decisive effect on the seismic response of the chimney structure,but the vertical earthquake has a great influence on the stress at the top of the structure,and its influence can not be neglected.(2)In order to simplify the design and calculation of this new chimney structure under earthquake action,according to the calculation method of the existing design specification,this paper has established the independent calculation model of the chimney structure without considering the interaction between the inner and outer cylinders,and it also has calculated it's seismic response.The response results obtained by this simplified calculation are larger,that is,the standard calculation method is partial to safety.(3)The number of inner cylinder segments and the connection forms of the inner and outer cylinders have a great influence on the stress and deformation of the FRP-steel sleeve chimney structure,especially the influence on the inner cylinder stress.In this paper,the influence of the number of inner cylinder segments,the position of the suspension point and the stop point and the number of nodes that limit the horizontal displacement of the inner cylinder on the stress and deformation of the chimney structure are studied.The calculation results have been compared and analyzed,and the paper provided a theoretical reference for the design and application of this kind of chimney structure.