The Seismic Performance Analysis Of A High Rise Composite Structure Building

With the highly development of society,the high rise building plays a very important role in the developing country and developed country.In order to make sure high rise building’s seismic performance,choosing a reasonable structural system is of great significance.The composite structure,as its name,is a kind of structure system which consists of several different kinds of material and members.It can exploit steel member’s and concrete member’s advantages such as bending strength,compression strength,bending stiffness,compression stiffness,bending ductility,compression ductility and building applicability to the full.As its obvious advantages of reducing structural weight,decreasing structural section size,improving construction process and so on,the composite structure system is one of the best high rise building systems for what China wants now.Although the development of steel-concrete composite structure is very fast,the study in this area is still far from demand and remains difference.The incompatibility between steel’s and concrete’s stiffness and strength may make steel and concrete share the resistance unreasonably.And it may effect the seismic performance of composite structure.A high rise composite structure in Shenyang is studied and the work condition of it in frequent earthquake,medium earthquake and rare earthquake is the main topic in this paper.The FEA model was established by Korean FEA software Midas Gen,the eigenvalue analysis and seismic analysis in the frequent earthquake and rare earthquake of it were studied.The response spectrum analysis and elastic dynamic time history analysis in frequent earthquake were analyzed.The pushover analysis and dynamic elastoplastic time history analysis in rare earthquake were analyzed.In pushover analysis,three different types of loading modes,namely,uniform acceleration loading,modal loading and normalized modal mass loading were applied in the X direction and Y direction of the structure.The base shear force-roof displacement curves,inner-storey drift angel curves,storey shear force curves and plastic hinge’s development condition of the performance point in three different types of loading modes were compared,so the seismic performance of it in rare earthquake was evaluated.In dynamic elastoplastic time history analysis,two natural waves and an artificial wave were applied on the structure,the structural roof displacement time history curves,inner-storey drift angel curves,storey shear force curves and plastic hinge’s development were compared,so the seismic performance of it in rare earthquake was evaluated.It can be concluded from the storey drift angel curves of frequent earthquake and rare earthquake that the structual stiffness of Y direction is smaller which should be strengthened.It should be paid more attention that the capacity spectrum curves and the elastoplastic deformation of performance point in three loading modes are different in pushover analysis.In the dynamic elastoplastic time history analysis,most of frame yielded deeply under three earthquake waves,the coupling beams of shear wall and shear wall around the strengthen layer yeilded.It can be concluded from pushover analysis and dynamic elastoplastic time history analysis in rare earthquake that the composite structure has a very good yield mechanism,the belt trusses of frame reinforced layers destroy before other structure members,the frame beams destory before shear wall and the shear failure is after the bending failure.Excellent yield mechanism can provide multiple lines of defence around the structure.As the structural stiffness in the Y direction is smaller than that of X direction,BRB was applied from the 10th floor to the 15th floor.The stiffness of Y direction increases obviously,the primary structure is optimized.