Study Of Multistage Series Non-proportion Damping Isolated Structure Under Earthquake

Isolation technique is a kind of efficient passive control technique Which isarranged isolation device. Such as the laminated rubber bearing and damper, so as toincrease the isolation layer damping, prolong the natural period of vibration, reduceseismic energy input to the upper structure, thereby decrease seismic response of theupper structure. To achieve the desired requirement."code for seismic design of buildings" that promulgated in2001which limitedisolation layer between upper structure and basement in part of isolation structure,and its application is limited. With the isolation technology rapidly development andresearch, the isolation layer position is no longer limited to the top of basement, therevision code (GB50011-2010) made expansion for isolation layer position, fromwhich "between upper structure and basement" change to "between basement, lowerstructure and upper structure", if damping of each structure have differentperformance, which constitute the multistage series non-proportion damping model.Based on the above reasons, this article studied it.Programming use MATLAB of multistage series non-proportion dampingisolated structure model and analysis structure response under earthquake thatcompares with result of Wilson-θ method. the results show the correctness of thismodel, reasonableness of multistage non-proportional damping matrix, and accuracyof analytical procedures. using this procedure comparatively analysis of multistageseries isolated structures with base isolation structure, the series isolated structurecushioning effects and substructure interstory drift.The results show that structure layer shear ration of the overall structure andpeak displacement of isolation layer tend to correspond to value of base isolation asthe low structural mass and horizontal stiffness increased, when substructure has onelayer and stiffness greater than4to6times of the upper structure horizontal stiffnessof ground floor, it can approximately analysis with base isolation structure. Isolationlayer of structure work to both the upper substructure and the lower substructure, havedual shock absorption effect. upper structure generated opposite force to direction ofstructure movement, so that the substructure vibration was obviously slacked; Seriesisolation structure basement resonance frequency is less than non-isolated structure,and the frequency response amplitude is smaller than non-isolated structure amplitude.With seismic intensity increases, the substructure interstory drift increases, the basement interstorey drift in near field earthquake is greater than the correspondingvalue of far field earthquake results in site class of Ⅰand III, the results contrast insite class of Ⅱ.