Research On Energy Dissipation Design For Eccentric Structure With Viscous Dampers

Due to the variety of functional requirements and the novelty of the design,the mass center often deviate from the rigid center in modern buildings.Lateral-torsional coupling vibration and stress concentration under the action of earthquakes will accelerate the destruction and collapse of eccentric structure.Energy dissipation technology provides a new method for controlling the displacement and torsion of eccentric structures under the earthquake,so it is the hotspot in the field of structure seismic research and application.In this paper,eccentric concrete frame structure with viscous dampers was taken as the research object,the dynamic response control effects of eccentric structure with viscous damper under earthquakes were analyzed.Distributions of damping coefficients in eccentric structure were studied,and a new vertical distribution method and a horizontal distribution method were proposed respectively.A design methods of single-layer eccentric structure and a separate design method of energy dissipation for multi-layer eccentric structure were advanced.The main research contents are as follows:(1)The characteristics and main types of viscous damper were summarized,and the common mechanical models of viscous damper were analyzed.The performance of linear viscous damper and non-linear viscous damper were compared.(2)Based on eccentric structure analysis model,the lateral-torsional coupling motion equations under uncontrolled state and controlled state were established.The seismic response analysis methods of energy dissipation eccentric structure were summarized,including the mode-superposition response spectrum method considering the torsional effect and the dynamic time history analysis method.(3)The single-layer eccentric structure with the viscous dampers was taken as the research object,and the design methods of energy dissipation for single-layer eccentric structure were proposed combined with the goals of maintaining elasticity and controlling torsion of structure during moderate earthquake.The center of the damping coefficient was established according to the eccentricity of the mass center and rigid center,and then the horizontal distribution of the damping coefficient was carried out.The new method and two commonly used horizontal distribution methods of the damping coefficient were used to strengthen a single-layer unidirectional eccentric structure model and a single-layer bidirectional eccentric structure model established by the finite element analysis software ETABS.The comparisons of the control effects between the three distribution methods verified the feasibility of the design methods of energy dissipation and the rationality of the horizontal distribution method of the damping coefficient.(4)The multi-layer eccentric structure with the viscous dampers was taken as the research object,and maintaining elasticity and controlling torsion of structure during moderate earthquake were taken as goals.A separate design method of energy dissipation for multi-layer eccentric structure was proposed considering the vertical distribution and horizontal distribution of the damping coefficient respectively.The multi-layer eccentric structure was regarded as a regular structure firstly,and the additional damping coefficient of each layer can be determined according to the additional damping ratio.After the additional damping coefficient of each layer was determined,the horizontal distribution of the additional damping coefficient was carried out according to the characteristics of the torsional control for the eccentric structure.Through the design of energy dissipation for a 6-layer eccentric structure model established by the structural design software PKPM and the finite element analysis software ETABS,the feasibility of the separate seismic design method was verified.