Seismic Reliability Analysis For Functional Utility System In Hospital

The great financial loss make people think deeply of seismic design method of nowadays after recent several intense earthquakes. Performance-based seismic design has became the developing trend of the seismic design method. Based on the thought of performance-based seismic design, an effective reliability-based procedure is presented to assess the capability of buildings to be functional after a seismic event of a given intensity. The function of a building depends on several cooperating services, which in turn are made up from a certain number of nonstructural components. Such a complex organization may be described in terms of a logical scheme. The project group has collected a large amount of data about a outpatient building of a hospital. When an earthquake strikes, hospitals are strategic infrastructures but are, at the same time, highly fragile and complicate. Emergency treatment, which made up from: Operating theaters; X Rays; Analysis laboratory; Pharmacy and so on, is the core of hospital operation. A logical scheme of emergency treatment is constructed in the paper. The seismic respond of reinforced concrete frame structure is given by a 3-D nonlinear dynamic structural analysis program CANNY through a multiple inputs nonlinear time history method. The deformation failure criteria is used to estimate the damage degree of the structure. The floor spectra for single supported secondary systems are developed to estimate the seismic force on the facilities. This paper discusses the difference between the floor spectra method and the simplified design expressions in seismic design code for nonstructural components and equipment in buildings. With reliability theory, for each nonstructural component a collapse criterion is defined, by which the strength is compared to the action load, both represented as random variables. The strength may be estimated according to the installation handbook. The failure probability of each nonstructural component is proposed through computation and analysis. The Fault Trees Analysis method is employed to analyze the emergency treatment function qualitatively and quantitatively. The function system can be reduced to a minimal cut-set representation. Each cut-set is a failure mode of the function. The fragility curves of system are calculated. Nonstructural components have different weightiness. The method enables to single out weak elements and potential sources of damage within the hospital and to develop optimal strategies for seismic retrofitting and rehabilitation. The anchored equipment will improve the reliability of system. Based on cost-benefit principles, a estimation mode is presented in the paper for the building function failure loss.