Study On Seismic Behavior Of Prefabricated Concrete Frame Structure With Intermediate-Connected Columns

Owing to a variety of advantages including: high construction efficiency,environmental protection,short construction period etc.,precast concrete structure has been a major form of construction currently and the trend of the future development of China's building structure.In the process of the promotion and development of prefabricated concrete structures,the safety problem is still the key issue.Compared to the traditional frame which assembly connection point is set at the bottom of the column,move the assembly connection to the middle of frame column is more suitable for the connection considering earthquake resistance,in addition,prefabricate the joint at the factory can decrease operational difficulty and better realize the design idea "strong joint".Based on the above-mentioned factors,the assembly connection point has been moved to the central of the column where the bending moment is comparatively much lower under earthquakes in this paper.It is expected that the performance of the precast concrete structure with intermediate-connected columns is better than that of the bottom-connected columns.Therefore,seismic performance of the precast concrete structure with intermediate-connected columns is researched in this paper.Firstly,finite element software SeismoStruct is adopted to analyze three quasi-static tests,in addition,the accuracy and effectiveness of the software are verified by comparing the simulated results with experimental results in previous study.Then,models using intermediate connection and bottom connection with different axial load ratios are calculated based on the above numerical simulation methods,the hysteretic curves,skeleton curves,displacement ductility,stiffness degradation and energy dissipation capacity of the models are analyzed.The results showed that the ultimate bearing capacity and the energy dissipation capacity of the intermediate-connected columns is higher than those of bottom-connected columns.In view of the fact that the mechanical model of the prefabricated column is not ideal due to the bending moment in the central of the column is not zero.The issue is discussed in the paper and a prefabricated subassembly is added as a supplement.The obtained results confirm the previous conclusions.Next,two 3-span 6-story prefabricated frames model are designed,which the assembly connection points are placed in the end of the columns and in the middle of the columns respectively.The collapse-resistant capacity of different frame are quantitatively evaluated and compared,with a seismic collapse fragility analysis based on an incremental dynamic analysis(IDA).Meanwhile,three frequent-level ground motions and three rare-level ground motions are input to the two structures for elastic and elastoplastic time history analysis.According to the analysis,the precast concrete structure with intermediate-connected columns is better than that of the bottomconnected columns in collapse resistance performance,and the maximum lateral displacement and drift angle of frame of the former is smaller than the later weather in frequent-level or rare-level ground motions.Finally,all the content of the whole study are summarized,and the inadequacy of this paper and the development of the subsequent research are presented.