Study Of Seismic Control On Tuned Viscous Mass Damper Coupled Wall System

The thesis proposes an innovative coupled wall system,named as the tuned viscous mass damper(TVMD)coupled wall system used for high-rise buildings.It is shown in the paper that this novel coupled wall system is very effective in reducing both the lateral drift and floor acceleration of a high rise building when subjected to strong ground motions,thus enhancing the seismic resiliency of the structure.Two seismic tuning design methods for TVMD coupled wall system are proposed in this thesis.Through numerical analysis and real-time hybrid simulation test,this thesis investigate the seismic control theory and seismic performance of the TVMD coupled wall system.A new tuned viscous mass damper(TVMD)is used in the TVMD coupled wall system,which can generate large inertial force and large damping force under small deformation and can be tuned to the main modes of the primary strcture.In this system,TVMDs are allocated to connect two adjacent wall piers in a zig-zag configuration.Such a strategic arrangement of TVMDs efficiently makes use of the vertical relative displacements of the adjacent wall piers induced by the wall's flexural deformation and enlarges the strokes of TVMDs,thus increasing their forces and efficiency.With the advantages,the TVMD coupled wall system can generates large damping force under small inter-story drift.Moreover,if with proper tuning design,the seismic responses of multiple modes can be surpressed.A numerical model of TVMD coupled wall is built by Matlab.A single-mode tuning design method based on the fixed point method is proposed.Modal analysis and elastic time-history analysis indicate that TVMD can increase the damping ratios of not only the tuning mode but also the modes of which the frequencies are lower than that of the tuning mode,and thus surpress the seismic responses of several modes simultaneously.Besides,the mode shapes of the primary structure remain unchanged.When tuned to the 3rd mode of the primary sturture,the maximum inter-story drift and maximum floor acceleration under design basis earthquake are reduced by 60% and 65% respectively.A multi-mode tuning design method using numerical optimization is also proposed and it is shown this method also can control modal responses of several modes simultaneously and achieve similar seismic performance as single mode tuning design method.A real-time simulation test of the TVMD coupled wall system was conducted to verify the seismic control performance of the system.In the test,only the TVMD in the top story was tested in the physical domain while the rest TVMDs and wall piers were calculated in the numerical model.The seismic responses obtained in the test are very close to the calculation results of the pure numerical model.It is shown from the test that the TVMD coupled wall system demonstates good seismic performance under different kinds of groud motions,etc.,near-fault earthquakes and far-field long-period earthquakes.The maximum inter-story and maximum floor acceleration under design basis earthquake can be surpressed by 64% and 76% respectively.Beside,the detuning effect due the stiffness change of the system after the structure is damaged in severe earthquake shaking is proven to be not significant,Considering the stiffness degradation,the maximum floor acceleration does not increase and the maximum inter-story drift increases by only 8%.Addition numerical simulation indicates that TVMD coupled wall system shows better seismic performance compared to reinforced concrete coupled wall system and conventional viscous damper coupled wall system.