Research On Seismic Behavior Of RC Frame Reinforced With Rocking Steel Support

RC frame-rocking steel support structure is a new type of structure system.The rocking steel support structure has a large in-plane stiffness and a special construction with a certain rotational capacity at the bottom,so that it can effectively control the lateral deformation mode of the structure in the earthquake.The system can be combined with energy dissipation and damping device to improve the the seismic capability of the whole structure,and the prestress can be applied to make the whole structure have self-resetting capacity.At present,some scholars have carried out systematic experiments and theoretical studies on the self-centering rocking structure system,and have achieved a series of research results.However,the research on strengthening existing RC frames with rocking steel support has not been involved.RC frame-rocking steel support based on existing RC frame design is taken as the research object and the seismic performance of RC frame-rocking steel support structure is focused on in this paper.The project is studied from three aspects: the experimental analysis and numerical analysis of seismic behavior of rocking steel support,the seismic performance analysis of RC frame-rocking steel support structure,and the design method of strengthening existing RC frames with rocking steel support.The main work and achievements of this paper include:(1)Numerical analysis and experimental study are carried out on the seismic performance of rocking steel support structure: The properties of the friction damper,such as preload,friction coefficient and maximum travel,determine the stiffness and energy dissipation capacity of the new type of rocking steel support structure.The prestressed bars can not only reduce the residual lateral displacement of the structure and provide the self-resetting ability,but also improve the bearing capacity of the steel support.(2)The seismic performance of RC frame-rocking steel support structure is numerically analyzed: The deformation mode and damage mode of the structure can be effectively controlled by attaching the rocking steel support structure with sufficient stiffness and strength on the RC frame.With the increase of the stiffness of the rocking steel support,the control effect of the deformation mode of the reinforced concrete structure becomes more obvious.Friction dampers installed at the bottom of the rocking steel support can significantly improve the seismic capacity and energy dissipation capacity of the structure and reduce the seismic response of the structure.At the same time,the structure can be self-centering by applying prestress.(3)The simplified method of RC frame-rocking steel support structure is studied: The simplified model of RC frame-rocking steel support structure proposed in this paper can effectively replace the refined model for elasto-plastic analysis,reduce the calculation workload,and facilitate the overall seismic performance evaluation of the structure in the rare earthquakes.(4)The seismic design method of RC frame reinforced with rocking steel support structure is studied: The seismic design method of RC frame reinforced with rocking steel support structure based on damage mechanism control proposed in this paper can effectively reduce the response of the structure in the earthquake.And make the response distribution of the structure floor tend to be uniform,which can achieve the expected damage mechanism.