Seismic Vulnerability And Resilience Assessment Of Grid Structures Considering The Effects Of Corrosion

Grid structure is widely used in public places such as stadiums,exhibition centers and airports in China because of its light quality,superior economy and good seismic performance.At present,research scholars have carried out a lot of research on the seismic performance of the grid structure and formed a perfect theoretical system.However,with the increase of service life,the grid structure also faces different degrees of corrosion problems,and the safety performance of the grid structure is greatly affected,which poses a serious threat to the major economic properties of the country and the life safety of the people.Therefore,it is particularly important to study the seismic performance of the grid structure considering the effect of corrosion.At the same time,maintaining the function of the building and achieving rapid recovery of the building function after the earthquake become urgent problems.Therefore,the assessment of the seismic resilience of structures has become an important research direction in the field of earthquake engineering.In order to have a better assessment of the damage mechanism and seismic resilience of the grid structure considering the effect of corrosion under the earthquake,this paper conducts seismic vulnerability analysis and seismic resilience assessment of the grid structure considering the effect of corrosion.The main research contents are as follows:(1)Analysis of the effect of steel corrosion on the mechanical properties of the grid structureThe corrosion process and mechanism of steel are systematically explained,the influence of different factors on the corrosion rate of steel is analyzed,and the relationship between the degradation of steel properties and the corrosion rate is quantified;the influence law of steel corrosion on the geometric parameters of structural members(cross-sectional area,crosssectional modulus of inertia,cross-sectional moment of inertia,etc.)is considered,and the study on the mechanical properties of steel members considering the influence of corrosion is carried out,and the numerical simulation of the members considering the degradation of material properties The results of the numerical simulation of the members considering the degradation of material properties are compared with the existing experimental results,and the accuracy of the simulation method is verified.(2)Seismic performance level and quantitative index of the grid structure considering the influence of corrosionBased on the qualitative description of the ultimate damage state of the structure in the Code for Seismic Design of Buildings(GB50011-2010),the damage factor is used as a quantitative index for judging different critical damage states according to the deformation damage criterion,and the corresponding structural damage model is obtained;the seismic response analysis is carried out for the grid structure under different corrosion degrees.The damage factor limit for different degrees of corrosion were obtained,and the damage assessment standard of the grid structure considering the influence of corrosion were established.(3)Seismic vulnerability analysis of the grid structure considering the effect of corrosionBased on the incremental dynamic time analysis(IDA)method,the seismic vulnerability analysis of the grid structure considering the effect of corrosion was carried out.20 typical ground motion were selected from the ground motion database(PEER,SEMS,ETMC)to carry out seismic response analysis on the corrosion-affected grid structure through ANSYS finite element software.The basic principles of seismic vulnerability analysis were explained,and the effects of parameters such as column cross-section and roof loading on the seismic vulnerability curves of the grid structure were investigated,and the seismic vulnerability curves of the grid structure under different degrees of corrosion were obtained.The seismic vulnerability curves are obtained for different rust levels,which provide a basis for seismic probability risk analysis and seismic resilience assessment of the grid structure considering the influence of corrosion.(4)Seismic resilience assessment of the grid structure considering the influence of corrosionThe seismic risk analysis and seismic vulnerability analysis are carried out for the grid structure considering the influence of material degradation properties,and the seismic probability risk assessment is carried out for the structure;according to the Standard for Seismic Resilience Assessment of Buildings(GB/T 38591-2020),the framework and process of resilience assessment of the grid structure considering the influence of corrosion are proposed,and the seismic loss and structural function recovery of the grid structure considering the influence of corrosion are obtained respectively.The function-time curves and threedimensional resilience surfaces of grid structures considering different load acceleration amplitudes(PGA)and rust rates are obtained to provide a theoretical basis for the seismic resilience enhancement of such structures.