Study On Influence Of Displacement Limit Of Viscous Damper On Structural Performance And Vulnerability

At present,the frequency of earthquakes has become more and more frequent and it has become one of the most severely damaged disasters faced by humans in natural disasters.The energy dissipation device is a new technology that can effectively reduce the earthquake action and ensure the safety of the structure.It has been widely used in practical projects,especially the application of viscous dampers.The viscous damper's performance may degrade or even fail during use or during a major earthquake.Compared with the common oil leakage phenomenon,the limited displacement of the viscous damper will have a great probability on the one hand.On the other hand,it will change the mechanical behavior of the damper and exit the energy-consuming working state.There may be a direct and adverse effect on the seismic performance of the main structure.Especially under the action of hyper-intensity earthquakes,it is necessary to consider how the state of the damper displacement beyond the limit stroke affects the collapse resistance of the structure.This is of practical significance to reducing earthquake disasters and improving the energy dissipation technology application system.This paper focuses on the influence of the mechanical behavior of the viscous damper with limited displacement on the structural performance.Based on the mechanical model of the restoring force of the limited viscous damper,the elastic-plastic analysis and vulnerability analysis of the energy-absorbing and shock-absorbing structure are conducted to examine the earthquake.Whether to consider the impact of the damper displacement limit on the seismic performance and collapse resistance of the main structure under the action.The main research content is as follows:(1)Review and summarize the traditional classical multi-viscous damper mechanical model,and newly explore the restoration force model of various failure modes of the damper.Analyze and discuss the characteristics of various mechanical models and their applicability.The successful application of the restoring force model considering the displacement limit ofthe damper in the elasto-plastic analysis of the energy dissipation and shock absorbing frame structure shows the practical value of considering the damper displacement limited recovery force model.(2)According to the reasons for the limited travel,define the case where the two kinds of viscous dampers use limited displacement: study the limited displacement of the viscous damper under the fortification intensity due to construction deviation or design error,and encounter Case of Viscous Damper Ultra Limit Displacement in Hyper-intensity Earthquake.(3)According to the viscous damper mechanics model considering the displacement limit,an elasto-plastic analysis model of the energy-absorbing and shock-absorbing frame structure is established to investigate whether the displacement limit of the damper is considered to be structurally seismic under the action of the fortified seismic intensity and the hyper-intensity earthquake.The impact of performance.The analysis results show that the function of hysteresis energy loss after the viscous damper displacement exceeds the limit is lost.At the same time,it also increases the support stiffness effect for the structure: the displacement angle between layers decreases,and the floor shear force increases.(4)In order to further examine the advantages and disadvantages of the above-mentioned impact on the performance of the main structure,an incremental dynamic analysis is performed on the elasto-plastic structure considering the viscous damper's ultra-limit displacement,and the variation of the vulnerability of the damper to structural earthquake vulnerability is examined.The failure mode structure is analyzed to reach the failure probability effect of each limit state including the collapse limit state.The results show that when the structure reaches the limit state of collapse prevention,the failure probability of the limit displacement structure of the viscous damper is considered to be higher than that of the structure without considering the limit displacement of the viscous damper,and the collapse coefficient is relatively low compared to that of the viscous damper.The device will exacerbate structural damage.Therefore,for the viscous dampers used in the normal design of a practical project,under the influence of a large earthquake,they may encounter the limit of travel over-displacement.At this time,the traditional damper mechanics model is still used and the seismic resistance of the structure will be overestimated.