Seismic Performance Assessment Of Reinforced Concrete Frame Structure With Energy Dissipation And Isolated Devices Based On FEMA P-58

In recent years,performance-based earthquake engineering(PBEE)has made great progress.However,the early PBEE theory has a lot of shortcomings,such as not considering the uncertainty of analysis,using the performance measures that are not easily understood by non-engineers,and not considering the non-structural components.The Pacific Seismic Engineering Center(PEER)of the United States has proposed a new generation of performance-based earthquake engineering theory,and promulgated the FEMA P-58,a code about seismic performance assessment of buildings in 2012.The seismic performance assessment theory presented in FEMA P-58 adopts the idea of total probability,considers the uncertainties of ground motion and structural response,and chooses performance measures which are easy to understand by non-engineers,such as repair cost,repair time,casualties and so on.This makes the performance assessment results have better applicability.Energy dissipation technology and isolation technology can effectively reduce the structural seismic response of buildings.Most previous studies have shown that the seismic absorption structure and isolation structure can reduce the structural response effectively,such as the inter-story displacement angle and other measures.However,the seismic losses of these buildings and the damage of non-structural components still need to be studied.This paper systematically introduces the basic method and process of building seismic performance assessment of buildings on FEMA P-58 theory.Firstly,a typical multi-story frame structure is designed.On this basis,buckling restrained braces and isolation bearings are added to form BRB-frame structure and isolated frame structure.The finite element models of three structures are established by ViPSea software based on OpenSees,and the appropriate seismic records are selected to analyze the structural responses of the three structures.In this paper,the Intensity-based assessment method is used and the processes of seismic performance assessment by FEMA P-58 is given.The structural response and seismic loss results of ordinary frame structure,BRB-frame structure and isolated frame structure under four seismic intensities are compared.The following conclusions are drawn:1)FEMA P-58 seismic performance assessment method selects performance measures which are easy for non-engineers to understand;adopts the idea of full probability to take into account the uncertainties in seismic loss assessment;uses Monte Carlo method to improve the accuracy of analysis and reduce the uncertainty in analysis;uses performance groups as a unit to conduct performance assessment,so that performance assessment can be specific to particular structural and non-structural components in buildings.2)The results of structural response analysis show that compared with the ordinary frame structure,the IDR of BRB-frame structure and isolation structure is reduced by 40%-60% in each intensity level,the acceleration of the top floor of isolation structure is reduced by 45%,and the acceleration of the top floor of BRB-frame structure is increased by 25%.The overall vulnerability analysis results show that the isolation structure has the best safety reserve under the three performance levels of "no damage","slight damage" and "medium damage",while the BRB-frame structure in this case has the best collapse resistance.3)The results of seismic performance assessment show that the use of isolation frame structure and BRB-frame structure can effectively reduce the repair cost and repair time of buildings under earthquake.Compared with ordinary frames,the repair cost and repair time of isolated structures under rare earthquakes can be reduced by 65% and 58%,and BRB-braced frame structures can be reduced by 47% and 34%.