Research On The Time-dependent Attenuation Law Of Seismic Performance Of Typical Fabricated Frame Joints And Prediction Of Structural Dynamic Seismic Damage During Service Period

In recent years,the prefabricated concrete structure has developed rapidly in China,but the steel bar connection method of the prefabricated concrete structure joints and the bonding of new and old concrete are significantly different from the cast-in-situ structure.Therefore,the seismic resistance of the prefabricated concrete structure performance will change over time as the age increases.In order to analyze the seismic performance of prefabricated concrete structure in service life at different ages,in this paper,we study the variation of seismic performance of the edge and middle joints of the prefabricated concrete structure as the age varies based on the time-varying characteristics of reinforced concrete materials in general atmospheric environment.To conduct this study,we used a prefabricated concrete structure in Nanjing as an engineering case and the ANSYS finite element software was used to study the variation of seismic performance of the edge and middle joints of the fabricated structure with varying age.the static elastoplastic analysis and dynamic seismic damage prediction of the fabricated frame structure are carried out using SAP2000 software.The main research results obtained in this paper are as follows:(1)The finite element software ANSYS was used to model the edge and middle joints of a prefabricated concrete structure in Nanjing and simulate the pseudo-static.The calculation results were analyzed and compared with the same cast-in-place joints.Based on the time-varying characteristics of reinforced concrete materials,the seismic performance of the assembled frame edge and middle joints in service period was calculated by ANSYS.The degradation of bearing capacity,stiffness and ductility of the intermediate joints and edge joints of the prefabricated concrete structure were analyzed according to the calculation results.(2)The prefabricated concrete frame structure model was established by using the finite element software SAP2000.The Pushover analysis of the prefabricated frame structure was carried out in the uniform loading and inverted triangle loading modes in the X and Y directions.The results show that the inter-layer displacement and inter-layer displacement angle of the building structure are in compliance with the seismic requirements.Although the plastic column is present in the beam column,it is within the repairable stage,and the plastic hinge distribution law also indicates that the structure meets the requirements of The seismic principle of strong column and weak beam.(3)Based on the previous mentioned analytical model,with the Pushover analysis of the prefabricated concrete frame structure of different service ages carried out by SAP2000,the performance point spectrum displacement under different ground motion intensity,and the ground motion parameters based on ground motion parameters in HAZUS99,we can calculate the time-varying vulnerability curve and the dynamic damage matrix of the structure separately.Finally,the dynamic damage prediction results of the structure were analyzed,and the main failure state of the structure under the ground motion of each strength and the variation law of the earthquake damage during the service period were obtained.