Research On Seismic Vulnerability Of Main Building Of Nuclear Power Plant With Steel Reinforced Concrete Frame-bent Structure

As the lifeline project of my country,the main plant of nuclear power plant needs to carry out a comprehensive and reasonable seismic analysis and evaluation of its structure to ensure the safety and reliability of the main plant of nuclear power plant under the action of earthquake.The theory of seismic vulnerability is an important way to evaluate the seismic performance of building structures.At present,there is little research on the vulnerability of the main building of steel reinforced concrete frame-bent structure nuclear power plants under earthquake action,therefore,it is of great significance and engineering application value to study the seismic vulnerability of the steel structure building.In this paper,the IDA method is used,based on the OpenSees numerical simulation platform,to build a steel plant structure,and the vulnerability analysis is carried out by inputting near and far field seismic waves to the structure.The main research contents are as follows:(1)The pseudo-dynamic test was carried out by selecting a partial span scale model representing the steel reinforced concrete frame and bent structure,and a finite element test model was established,then the ground motion records were input into the finite element model for elastoplastic analysis,and the results were consistent with the test results.The comparison verifies the rationality of the establishment of the finite element model of the main building of the steel-reinforced concrete frame-bent structure nuclear power plant based on OpenSees,which provides a basis for the selection of the prototype structure parameters of the steel-reinforced concrete frame-bent.(2)The maximum inter-layer displacement angle is determined as the engineering requirement parameter for vulnerability analysis,and PGA is the ground motion intensity parameter,and 20 suitable near and far field seismic waves are selected from the PEER database for preliminary preparation for seismic vulnerability analysis.And through the frequency spectrum analysis to explain the characteristics and differences of near and far field seismic waves.(3)The dynamic time-history analysis of the seismic waves with the corresponding intensity in the three-level fortification phase of the steel building structure shows that the maximum inter-story displacement angle appears at the top of the structure.On this basis,with the input direction of the ground motion,the concrete strength level,and the section size of the steel column as variables,the IDA method was used to analyze the parameter sensitivity of the seismic vulnerability of the structure.The analysis results show that due to the difference in the overall lateral stiffness of the structure,the ground motion along the lateral input of the structure is greater than the longitudinal damage;the appropriate increase in the strength level of the concrete can effectively reduce the damage of the structure;The size of the center column can more effectively reduce structural damage.(4)By comparing the vulnerability curves of the main building of the nuclear power plant with steel concrete frame-bent structure under the action of near-field and far-field earthquakes,the deviation probability of the near-fault ground motion relative to the far-field vibration is obtained,and the near-fault earthquake is considered for the structure reference recommendations are provided for optimal settings of seismic performance under dynamic damage characteristics.The analysis results show that the near-fault ground motion will generally cause greater damage to the structure,and the appropriate reinforcement of the steel column section size is a more effective measure to control the structural damage.In this paper,through the research on the seismic vulnerability of the steel structure,the key design parameters are set as variables to quantify the impact of the parameter changes on the seismic performance of the structure,and fully evaluate the damage of the structure,which can provide a reference for the seismic design of such structures.