Comparative Study On Design Method And The Value Of Bearing Performance Between China And The United States

With the wide application of isolation technology,the isolation design is becoming more standardized.China provides seismic isolation design methods in Chapter 12 of the Code for Seismic Design of Buildings(GB 50011-2010)(hereinafter referred to as “anti-regulation”).At present,the “Design Standard for Building Isolation” prepared for the isolated structure(Draft for Comment)(hereinafter referred to as the new standard)has entered the approval stage.This paper is aimed at the design of the isolation structure in the anti-regulation,the new standard,the American standard ASCE 7-16 and ASCE 7-10,and the difference in the performance of the isolation bearing.In the national code,the contents of the isolation design method and the value of the bearing performance are compared.The difference between the standard isolation design method and the bearing performance value of the two countries can be discussed,which can be used to revise the building isolation specifications and understand the relevant personnel.Familiar with the US seismic specifications for reference.According to the principle that the surface peak acceleration of 2% of the 50-year surpassing probability is basically equal,the corresponding parameters of the US norm seismic action are determined by transforming the ground motion parameters,and the test results of the test results of the same group are compared with the test methods of the two countries.And selected two identical frame structures for seismic isolation design accordingto the two countries' specifications.The seismic response of the structure is calculated by the bottom shear method,the mode decomposition reaction spectrum method and the time history analysis method,and the calculation results are compared and analyzed.The specific content is as follows:(1)Analyze the seismic isolation design requirements of China and the United States and the acceleration design response spectrum,and convert the seismic parameters of China and the United States to compare the similarities and differences of the isolation design methods in the Chinese and American norms.(2)Introduce the definition and classification of the bearing performance factors of the American standard ASCE 7-16,and calculate the test results according to the mechanical performance test data of the same group of lead rubber isolation bearings.The post-yield stiffness and yield strength of the bearing,as well as the thermal effect affecting the performance of the bearing,compared to the different testing methods,and the US ASCE7-16 test method has a range of standard requirements,which can provide reference for the revision of the new standard.(3)Introduce the design method of the equivalent lateral force method in the ASCE specification and the difference of the bottom shear method in the anti-regulation.Take the6-story frame isolation structure model as an example.In the similar site categories of China and the United States,the above method is adopted.The model is separately isolated and compared with the vertical distribution of seismic force.The results show that ASCE 7-16 considers the weight of the structural isolation layer,the structural period and the equivalent damping ratio are more in line with the actual project,which can provide the new subscript shear method.reference.(4)According to the design norms of China and the United States,the time-history analysis and calculation of the 6-story frame isolation model and the 18-story frame shear wall isolation model are respectively carried out,and the differences of the method of selecting seismic waves are explored,and the calculation results are analyzed.The resultsshow that the ASCE 7-16 seismic wave method can reduce the dispersion,and the seismic response of the Chinese seismic isolation model is within the upper and lower limits of the seismic response of the US isolation model.(5)Introduce the iterative principle and calculation method of the new isolation specification,and iteratively calculate the same isolation model according to the new isolation specification response spectrum and the US ASCE 7-16 specification response spectrum,and explore the different iterative methods.The seismic model is analyzed and summarized by the mode decomposition reaction spectrum method.The results show that the structural response calculated by the ASCE 7-16 specification is roughly equivalent to the level of the earthquake in the new isolation design specification,and the structural response of the earthquake in the new isolation specification is on this.Within the lower limit.