Study On Dynamic Response And Seismic Performance Of RWMF

In recent years,earthquakes have occurred frequently in the world,and the frame structure during the earthquake is easily collapsed,and it causing a great threat to life safety and property.Therefore,it is extremely important to reduce the earthquake hazard.The rocking wall-moment frame system is a new type of seismic structure,which can improve the story yielding of the frame and reduce the inter story drift.It has great application prospects in the field of seismic reduction.At present,the research on rocking wall-moment frame mostly focuses on inelastic behaviors such as hysteretic behavior,quasi-static test and ultimate bearing capacity,and lacks theoretical research on its dynamic response.This paper mainly focuses on two different types of rocking wall-moment frame(two-point swing and base articulated).The theoretical analysis and seismic performance research are carried out,and the excellent seismic performance of the rocking wall-moment frame system is verified.The main research contents of this paper are as follows:(1)The dynamic response of a two-point swing single-degree-of-freedom rocking wall-moment frame and a two-degree,of-freedom rocking wall-moment frame with a prestressed cable under near-fault pulse excitation are studied,and the equations of motion are derived.(2)The FE model of the rocking wall-moment frame of a two-point swing style is established.The dynamic response under four sinusoidal pulses excitation is obtained,and compare to the theoretic result It is shown the dynamic equations of the multi-degree-of-freedom structural system are still a single degree of freedom,which is a function of the wall rotation angle.The dynamic equations of the multi-degree-of-freedom rocking wall-moment frame structure can be transformed into a single-degree-of-freedom equation about the wall rotation angle.(3)Taking two-degree-of-freedom structure of the two-point swing style as an example,the dynamic response under the excitation of the near-field pulse ground motion was analyzed.The frame displacement history and the wall rotation angle under the ground of sinusoidal pulse and cosine pulse excitation are obtained.The effect of the mass ratio,natural vibration period and wall shape on the seismic performance of the structure is studied.The results show that the natural vibration period of the frame has a significant influence on the rotation angle and displacement response of the rocking wall.The shape coefficient has little effect on the dynamic response of the rocking system,and the influence of the mass ratio is more complicated.(4)The displacement response spectrum of the single-degree-of-freedom rocking wall-moment frame structure of the two-swing style under different site conditions was established,which can be used for the seismic design of the rocking wall-moment frame structure.(5)Based on the Lagrange equation,the dynamic equations of the base articulated rocking wall system under seismic action are established,and verified by finite element software simulation.(6)The dynamic response of the RWMF of base articulated style under the excitation of the ground motion is analyzed.The effect of the mass ratio,natural vibration period and wall shape on the seismic performance of the structure is studied.(7)The elastoplastic model of the rocking wall-moment frame structure of the base articulated style is established and static elastoplastic analysis and dynamic time history analysis is studied.Inter story drift of a frame structure,a full height RWMF,a half height RWMF,a frame-shear wall are compared,and confirms that the rocking wall structure has superior seismic performance.