Seismic Performance Analysis Of Precast Concrete Frame With Braces

At present,precast buildings in China are mainly composed of assembled monolithic concrete structure system.In this system,the lateral resistance of assembled monolithic concrete frame structure is limited,and there are still many wet operations in the construction site.Although the assembled monolithic concrete frame shear wall structure has good lateral resistance,its construction is more inconvenient.In order to make the precast structure have good lateral resistance and fast construction speed,a precast concrete frame with braces system（PCF-B）is proposed.The structure adopts fully-prefabricated concrete beam,column,and steel braces.In this paper,we established the PCF-B structure’s model using the finite element software ETABS.The effects of different brace types on the structure’s seismic performance are studied by static elastoplastic analysis and dynamic elastoplastic analysis,which including steel brace,buckling restrained brace,and self-centering brace.To provide a reference for engineers in structural design,The influence of the stiffness ratio between the brace and the frame on the seismic performance of the precast concrete frame with buckling resistant brace（PCF-BRB）,and the self-centering brace parameters on the precast concrete frame with self-centering braces（PCF-SCB）are explored.The main contents and results are as follows :（1）The reasonable constitutive relation and suitable element are selected in ETABS software,and the model of steel brace,buckling restrained brace,and self-centering brace member and its corresponding brace frame substructure model are established,and the finite element model was verified by several existing experimental results.The simulation results of the finite element model are in good agreement with the experimental results in a large amount of literature,proving the effectiveness and accuracy of the finite element model.（2）The four and 12 story PCF-B structure models with steel brace,buckling restrained brace,and self-centering brace are established.The structure’s seismic performance and the influence of different brace types on the structure are studied by static elastoplastic analysis and dynamic elastoplastic analysis.The results show that the seismic performance of the PCF-BRB structure and the PCF-SCB structure are better than the PCF-SB structure.（3）A series of 4-story and 12 story PCF-BRB structures with different stiffness ratios are established.The influence of stiffness ratio between the brace and the frame on the PCF-BRB structure’s seismic performance is studied by static elastopl astic analysis and dynamic elastoplastic analysis.According to the analysis results,considering the effect of brace increase and the influence of brace on the seismic performance of frame columns,it is suggested that the reasonable range of stiffness ratio of low-rise structure should be 1.5≤k≤3.0.The acceptable range of stiffness ratio of high-rise structure should be 3.0≤k≤4.0,（4）A series of models of PCF-SCB structure are established.Among them,self-centering braces have different post-yield stiffness ratio and energy dissipation ratio.The influence of post-yield stiffness ratio and energy dissipation ratio of self-centering braces on structure’s seismic performance is explored through dynamic elastic-plastic analysis.According to the analysis results,it is suggested that the post-yield stiffness ratio can be taken as 0.01;the energy dissipation ratio can be taken as 1.5 to achieve a good balance between the maximum and residual inter-story drift ratio..