Study On Seismic Vibration Control For Unequal Height Portal Frame Structure

The earthquake happens very frequently in China and it’s damage to the buildings very serious.The portal frame structure which is one of the most extensively domestic applied form of the structure, is applied in a variety of architectural form, Unequal height portal frame as one of the portal frame structure form is very commonly applied , So studying on Seismic vibration control for unequal height portal frame structure is a very important practical significance. Viscous damper is designed to dissipate seismic energy structure, reasonable arrangement of the damper can be consumed most of the input structure of seismic energy, reduce the displacement of structure, and improve the seismic performance of the structure.Introducing viscous damper to the portal frame structure as the energy-dissipated structure damping device, which is less applied in practic as well as in this area of research .This study also Provides a reference basisis to portal frame design and energy-dissipated structure.This paper expounds the structure of the viscous dampers, classification and mechanical characteristics, and clearly put forward the fast nonlinear analysis method(FNA) ,which one of the time history analysis method. The seismic vibration control analysis methods selected in this paper belongs to the“Fast Nonlinear Analysis (FNA) " method of partial nonlinear problems, which has higher accuracy and efficiency.Based on the the working model of unequal height portal frame structure , this paper arranges time history analysis using SAP2000 limited software. SAP2000 software in finite element method is used to establish the analysis model and to make mode analysis. According to its period and formation, the dynamic characteristics of the structure are mastered, then viscous dampers could be set up. By inputting seismic wave, different dynamic response of the structure between pre and post using viscous dampers is compared, and consider other factors, reasonable setting manner is selected. Then, damping effect of the structure is studied by inputting different spectrum characteristics seismic wave. Damping effects are different in terms of different seismic waves for spectral characteristics.In order to get more accurate results, we need to adopt a number of seismic waves to calculate and take the average number. Damping parameters will directly affect the energy-dissipated structure, under the same seismic wave comparing different dynamic response of the structure between pre and post using viscous dampers, then get the reasonable damping parameters matching. On the basis of controlling the used number and observing the damping effect, it can be concluded that arranging it on the portal frame structure is the most reasonable position.