Aseismic Performance Improvement And Economic Analysis In Existing Medical Buildings

The lack of overall planning and conceptionin the development of medical infrastructure has seriously restricted the quality of medical services andthe working efficiency of hospitals;Therequirements for the seismic performance of medical buildings have been increasingly high,but the performance of buildings has been decreasing year by year,and there are some potential safety hazards in certain buildings;Due to the large investment,high energy resources consumption,high operating costs and great impact on the surrounding environment,the state and local governments have promulgated relevant policies to curb the blind expansion of public hospitals.Due to theserequirements for the retrofit and reconstruction in medical building,whichinclude the higher seismic performance demand,the uninterrupted function of building;the unaffected overall medical environment;the relatively short retrofit period,the retrofit of medical infrastructure are difficult in all kinds of contradictions.The performance-basedmethodsshould be used to improve the seismic performance of the existing medical buildings,which will be the main approach to solving the contradictionbetween poorseismic performance and higher demands of medical services.Taking the outpatient building of a certain hospital in Beijing as an example,and theseismic performance improvement of medical building at different earthquake levelsbased ondifferent approaches,which includeseismic strengthening technology,energydissipation technology and seismic isolation technology,are measured by five quantitative indicators(displacement-based index,peak acceleration-based index,earthquake damage index,force-based index and energy-based index).Comparisons of the seismic performance,economy and retrofit modesbetween these three methods are made,and the application scopes of these three approaches are specified,which provide the bases for the seismic performance improvement of engineering structures.These five quantitative indicators are capable ofcomprehensively characterizing the seismic performance of load-bearing parts,internal and external partition walls,as well as the earthquake damage of facilities and instruments;Performance-based design procedures are desirable to meet the seismic performance requirements and to simplify the process.Performance-based conceptual design is an important means to improve the seismic performance of structures and to achieve these goals of safety,economy,rationality,effectiveness and practicality.Furthermore,the relevant algorithm is employed to check the results of the additional damping ratio and the horizontal damping coefficient of the time history analyses,so as to ensure the structural safety and the economic efficiency of the scheme.The performance-based evaluation method can be used to assess structural performance underfortification earthquakes and rare earthquakes;Generally,seismic strengthening technology only satisfy the original designobjective and can be applied to the non-medical auxiliary buildings.The energy-dissipation technology can effectively reduce the earthquake damage of the main structures and reduce the structural displacement responses,but this approach subtlelyreduce the floor acceleration,and it can be applied to medical buildings with relatively important uses but without valuable equipment.The seismic isolation technology has significant effects on reducing structural earthquake damages,displacement responses and the attenuation of floor acceleration,therefore,it can be utilizedin medical buildings which store valuable equipment.In order to achieve the expected performance objectives,the cost of the energy dissipation technology is the lowest,followed by the isolation reinforcement scheme,and the cost of seismic strengthening is the highest.Theperformance-basedseismic strengthening methods will be widely used in the lifeline systems such as medical buildings.