Seismic Performance Analysis Of Combined Design Of Medical Buildings In High Intensity Area

In earthquake relief,hospitals are lifeline projects that undertake rescue missions.In the "Design Standards for Building Isolation" implemented in September 2021,it is clearly proposed that hospitals,schools and other public buildings with dense personnel in highintensity earthquake areas must adopt shock reduction and isolation technology.In recent years,the combination of seismic isolation device has been applied gradually in engineering.However,the design of seismic isolation device other than seismic isolation layers is very rarely used in our country.In this paper,taking the inpatient department of a hospital as the research object,it is proposed to add an energy dissipator to the upper part of the base-isolation structure to form two kinds of combined structural systems of base-isolation + flexion confinement brace(BRB)and base-isolation + viscous damper.ETABS were used to establish the uncontrolled structure,isolation structure,base isolation +BRB structure,base isolation + viscous damper structure for modal analysis and time history analysis.According to the different advantages of the dampers,both BRB and viscous dampers are arranged in the upper part of the base isolation structure,and three schemes are formed according to the different placement positions.The influence of the two placement positions of dampers on the seismic performance of the isolation structure is compared and analyzed.The main conclusions are as follows:(1)Compared with the non-controlled structure,the natural vibration period of the isolated structure is about 3.6 times longer.When BRB is added to the upper part of the isolated structure,the structural stiffness increases and the natural vibration period decreases slightly.Adding a viscous damper to the upper part of the isolated structure has no effect on the natural vibration period of the structure.(2)The control effect of seismic performance indexes such as interstorey displacement Angle,interstorey shear force,interstorey displacement and vertex acceleration of base isolation + viscous damper structure is better than that of base isolation +BRB structure under frequent earthquakes.Under rare earthquakes,the control effect of base isolation +BRB structure on interlayer displacement Angle and interlayer displacement is better than that of base isolation + viscous damper structure.(3)By comparing the three schemes of mixed damping at the upper part of base isolation,it can be seen that the scheme where BRB is arranged on the floor with large displacement Angle between floors and the viscous damper is distributed on the bottom floor has the best control effect on the base shear,vertex displacement and acceleration of the structure.From the Angle of displacement between floors,this layout scheme can effectively improve the deformation of floors with larger displacement angles,and has the best control effect on the deformation of isolated floors.From the perspective of energy dissipation,the dampers in this scheme have the highest energy dissipation rate and the best energy dissipation effect.(4)The seismic performance of the hybrid damping scheme for the upper part of the base isolation structure is verified.From the perspective of vertex displacement,the control effect of the combined structure with BRB placed on the floor with large displacement Angle between floors and the viscous damper distributed on the bottom floor is close to that of the base isolation+BRB structure.From the perspective of base shear and maximum inter-storey displacement Angle,the control effect of this arrangement scheme on the base shear and maximum interstorey displacement Angle is obviously better than that of the structure with a single damper on the upper part of the base isolation.