Seismic Vulnerability Analysis And Seismic Performance Evaluation Of Bar-based Structures Based On Probability

Seismic vulnerability can be defined as the probability of occurrence of damage to the structure under certain seismic intensity,which can provides an effective way for the risk assessment of the structure through the structural seismic vulnerability analysis available at different levels of earthquake.Therefore,the structure of the seismic performance evaluation studies based on seismic vulnerability analysis is particularly important.In this paper,first,a reinforced concrete frame structure is taken as an example to study the probability-based seismic vulnerability of a structure.Then this research method is applied to the seismic reticulated shell structure failure probability analysis,form which seismic fragility curves reticulated shell can be obtained,and thus the reticulated shell structure seismic performance evaluation can be conducted.In this paper:First,seismic fragility analysis methods and theories related are provided.Based on this method,a nine-story model of reinforced concrete frame structure is established,and its seismic fragility curves are obtained at 50 seismic loads.By analyzing the fragility curves,it was found that the probability of collapse of the structure is low under strong earthquakes.This structure is of good seismic performance and can meet seismic standards.At the same time by comparing the degree of dispersion of seismic fragility curves under 50 and 40,50 and 30,50 and 20,50 and 10 ground motion records respectively,it was found that using 30 ground motion records for the framework of structural seismic vulnerability analysis and calculation can meet the accuracy requirements.Then the reinforced concrete frame structure seismic fragility analysis method is applied to single-layer reticulated shell.The single layer reticulated spherical shell and single layer cylindrical reticulated shell structure are taken as examples,and their respective seismic fragility curves are obtained and analyzed.The result shows that single layer reticulated shell structure is of good and stable performance and can meet structural seismic design standards,namely,the good structural stability of this structure can earn people the time to escape when an earthquake begins to crack the ground and destroying the houses.By comparing the fragility curves gained when using respectively 50,40,and 30 seismic waves,it was found that 30 samples of ground motion can meet the accuracy requirements as for single layer reticulated spherical shell and single layer cylindrical reticulated shell structure during seismic fragility analysisAt last,in this paper,seismic fragility analysis are conducted under reticulated shell strength model and dynamic instability model and respective seismic fragility curves under are obtained.The results of comparing those seismic fragility curves indicate that the seismic fragility curves and intensity curves under dynamic instability model share the same pattern of variation and are in line with the requirements for seismic performance cylindrical reticulated shell required by reticulated shells seismic code.This shows that it is feasible to conduct structural seismic vulnerability before dynamic instability based on the performance level and damage indicators of reticulated shell.Vulnerability analysis based on the probability of an earthquake of seismic vulnerability for truss structure analysis proves efficient,and the results of the analysis are in consistent with the current seismic code.It provides a simple and reliable method for the Probabilistic Risk Assessment of structure.