Seismic Response Analysis And Multi-objective Optimization Of Semi-rigid Precast Concrete Frames With Mid-isolated Story

Precast concrete structure realizes the industrial production of building structure,which can improve the construction quality and shorten the construction cycle,reduce energy consumption and is more conducive to environmental protection.It has been vigorously developed by the country.However,due to the existence of semi-rigid connection,it reduces the overall stiffness of the structure and limits its development in high intensity areas.Mid-story isolated technology is a structural vibration control technology developed in modern times.It can be applied to building structures with large differences in stiffness.The existing engineering examples have verified its effectiveness in improving the seismic performance of the structure and ensuring the safety of the structure under large earthquakes.Therefore,the application of mid-story isolated technology in precast concrete structure can greatly improve the applicable height and number of storys of precast concrete structure,It makes the structure more economical and safe,and can also promote the use of precast buildings in high intensity areas,which has great engineering value and broad application prospects.In this paper,a new type of semi-rigid precast concrete frames with mid-isolated story is formed,PC connection is considered as semi-rigid connection,and the dynamic equation of semi-rigid precast concrete frames with mid-isolated story is established.The seismic response of the structure under horizontal earthquake is solved by Matlab programming with appropriate methods.Through multi-objective optimization of the structure,the hybrid mode and connection parameters of the structure are determined.The research results of this paper are as follows:(1)A simplified method for seismic response analysis of mid-story isolated structures considering semi-rigid connection parameters(stiffness parameters,location parameters)and parts(beam end and column end)is proposed.By combining the precast concrete structure with semi-rigid connection and mid-isolated story,a new semi-rigid precast concrete with mid-isolated story is developed,the dynamic equation of semi-rigid precast concrete frame with mid-isolated story is established,and the appropriate method is used to solve the structure under horizontal earthquake with Matlab programming,so as to obtain the seismic response of the structure,The accuracy of the seismic response solution method of semi-rigid precast concrete frame structure with mid-isolated story programmed by Matlab is verified by using finite element analysis method.(2)Based on the above simplified method,the stiffness of semi-rigid connection,beam and column section size,isolation layer position and parameters of isolation bear are optimized in the elastic stage.Firstly,the appropriate mathematical optimization model is established,the appropriate algorithm is selected for the multi-objective optimization of the precast concrete mid-story isolated structure,and the optimization algorithm flow and the implementation process are given.Finally,a 13 story frame structure with mid-isolated story is optimized by SQP algorithm and inter-point method,and the optimization results obtained by different algorithms are compared.The rationality and applicability of the optimization results are studied and verified,and the reasonable distribution positions of isolated story and semi-rigid connection in the structure are summarized.(3)When the hybrid structure enters the elastic-plastic state,the multi-objective optimization under large earthquake is carried out by using NSGA-Ⅱ algorithm.Based on the elastic optimization in the third chapter,continue to carry out the elastic-plastic optimization of the structure under large earthquakes,use appropriate elastic-plastic analysis methods to calculate the seismic response of the structure,and select appropriate optimization algorithms to carry out the multi-objective optimization of the structure,so as to ensure that the structure has sufficient strength,deformation and energy dissipation capacity.Through Matlab programming optimization,a series of Pareto solution sets are obtained,the relevant parameters after structural optimization are obtained,and the rationality of the optimization results is verified.