Research On Performance Design Method Of Isolated Reinforced Concrete Frame Structure

RC base-isolated frame structures have shown good seismic performance in previous earthquake.Now the seismic isolation technology is also widely used in buildings with high performance requirements.However,the research on the design method of isolated structure and the application of isolation technology started late in our country.As the main method of isolation design,the division design method has some limitations.In the performance design of RC isolated frame structure,it’s one of the keys on how to efficiently estimate the response of isolated structure under rare earthquake.In order to comprehensively evaluate the seismic performance of the isolated structure,besides determining the performance objective and quantitative index of the main frame structure,it’s particularly important to research the damage performance of isolation bearing.Because the dynamic characteristics and damage mechanism of different structural types are different,it has practical significance to compare the seismic performance on of different types of structures.Based on this,the main research contents and conclusions of the thesis are as follows:（1）Simplify the isolation structure into 2-DOF and SDOF model to realize the dynamic characteristics and principles of the isolated structure.In this thesis,the displacement calculation method improved via equivalent linearization,a fast performance design method of isolation structure based on SDOF,is proposed.And the parameter calculation formula is deduced to reasonably estimate the response of isolation layer under rare earthquake,determine the design objective parameters,and improve the preliminary design efficiency on isolated structures.（2）The rapid performance design method was applied to a seismic isolated teaching building in highly seismic area,and the preliminary design and parameter analysis of the base isolated structures were carried out to give some suggestions to improve the applicability of this method.ETABS and Matlab software were used to calculate and analyze the 3D and SDOF base-isolated structures.The results of response under rare earthquakes were compared with the results of rapid performance design method to verify the accuracy and rationality of this method.（3）Combined with the rapid performance design method of isolated structure based on SDOF,the implementation process of isolated RC frame structure performance design is given.The relationship between performance level and quantitative index was summarized,the test data of rubber bearings damage were counted,and the performance level of bearings damage was divided.The structural components and materials that need to be analyzed by Perform-3D were pretreated.In order to conduct rapid elastic-plastic analysis of isolated structures,based on the modified Takeda model and Newmark-β method,this thesis compiled "Nonlinear Analysis Tool for Isolated Structures V1.0",and compared literature tests with finite element models to verify the reliability of the program.（4）The elastic-plastic analysis between the isolation structure and other types of structures under rare earthquakes is carried out,and the seismic performance of the isolation structure is evaluated and compared.Among several types of structures,the isolated structure component has minimum plastic damage degree and peak acceleration,and its control effect of displacement is the best.The max displacement of the isolated structure is 35% of the frame structure.The max displacement of the damping structure is 53% of the frame structure.Although the frame-shear wall structure has good seismic performance,its peak acceleration is maximum.In contrast,isolated structures are more suitable for buildings with expensive decorations and important equipment inside.The IDA of the isolated structure is carried out,and it’s suggested to comprehensively consider the damage of upper floors and isolation floors,and the damage degree of the most severely damaged layers should be taken as the overall damage degree of isolation.The Nonlinear Analysis Tool V1.0 was used to analyze the vulnerability of the isolation structure,and the vulnerability curves of the superstructure and the isolation layer showed a staggered upward trend.