Isolation Mechanism Research Of Rural Buildings Structures Supported On Hysteretic Slide-limited Friction Base-isolated System

Earthquake damage have shown that the village construction is vulnerable to earthquake shaking and is the worst hit when the quake happened,so it is imperative to improve the against earthquakes of village construction, among which base isolation is an effective way. Energy method has attracted much attention in the researches because of its unique advantages for many years.The accumulation of energy in bae-isolated sliding systems has great something to do with the energy dissipation of isolation layer and the destruction of superstructure, and the larger cumulative energy maybe lead to the destruction of base-islated sliding systems,so most of the researches on base-islated sliding structure,even the other isolated structure, focus on the accumulation energy,and it’s fine,but the instantaneous energy maybe connected with the destruction of base-isolated sliding system greatly as they can not be ignored for the traditional non-isolation structure.The sliding processes back and forth of isolation layer for base-isolated sliding structure is very complicated during the earthquake,The transformation of the cumulative energy and the instantaneous one are exercises a great influence on the state of isolation layer,thus affect the isolation effect,so failure mechanism of base-isolated sliding system for hysteresis variant of towns and villages is studied from the two aspects of the cumulative energ and instantaneous enegy.The sensitivity of ground motion characteristic and structural characteristics to multiple accumulated energy indicators of base-isolated sliding system for towns and villages structures are analyzed adopting the orthogonal experiment method.The concept of relationship spectrum between energy response is put forward and studied,and the energy spectrum of cumulative input and comprehensive energy dissipation are also researched.The difinition of instantaneous energy for base-isolated sliding structure is given based on the one of the traditional non-isolated structure.The time range of the maximum of the instantaneous energy and comprehensive energy for base-isolated sliding structure are contrasted,and theinstantaneous changes of energy for base-isolated sliding structure under the action of earthquake are revealed,and the spectrum of instantaneous input energy is studied in the end.The following work are done around the above contents:(1) The concept of comprehensive energy dissipation ratio is put forward for the energy consumption characteristics of hysteresis variant base-isolated sliding system,and the sensitivity of ground motion characteristic and structural characteristics to the accumulated input energy,the ratio of comprehensive energy dissipation,the ratio of friction energy dissipation and the displacement of isolation layer are analyzed adopting the orthogonal experiment method,and the results suggest that the above-mentioned response indicators are more sensitive to the natural period of superstructure and friction coefficient of isolation layer,but are relatively insensitive to the stiffness ratio between the stiffness of isolation layer before yield and the one of superstructure, the mass ratio between the superstructure mass and the one of isolation layer,the yield displacement of isolation layer and the second stage stiffness coefficient of limit switch.(2) The response relationship spectrum of base-isolation sliding structure,namely the one between the comprehensive energy dissipation and the input energy and the other one between the comprehensive energy dissipation and the maximal displacement of isolation layer,are put forward and studied.Results show that the influence that the structure parameter on the two response relationship spectrum has something to do with the site conditions,and the natural period of superstructure has a great influence on the two response relationship spectrum and the ratio of stiffness and the ratio of mass have small one on them under all kinds of the site conditions.(3) The comprehensive energy dissipation symbolizes the isolation effect.Researches show that the friction coefficient of isolation layer has a significant impact on the total input energy spectra and the comprehensive energy dissipation,and the influence of the parameter on the comprehensive energy dissipation has something to do with the frequency characteristics of the seismic oscillation.The effect that the ratio of stiffness on the two energy spectrum has something to do with the natural period of superstructure,and the ratio of mass has a small influence on the two energy spectrum on the whole.(4) In view of the complexity of base-isolated sliding structure,the design spectral of the total input energy and the comprehensive energy dissipation are studied and gained under the conditon that the friction coefficient of isolation layer is 0.07 and the restoring force model of limit swith is the ideal elastic-plastic model,and the above researches content lay a foundation for the follow-up studies of base-isolaton sliding structure.(5) The concept of instantaneous energy for base-isolated sliding system of town and village structures is put forward based on the one of the traditional non-isolated structure,and the time range of the maximum of the instantaneous energy and comprehensive energy are contrasted.The results show that the time frame on which the instantaneous input energy and the comprehensive energy dissipation appear their maximum maybe inconsistent although they are close,and the two time range on which the above instantaneous energy appear their own maximum have something to do with the natural period of superstructure.On the time range that the instantaneous input energy achieves its maximum the instantaneous comprehensive energy dissipation is perhaps zero or small.(6) The instantaneous input energy spectrum of base-isolated sliding structure in rural areas is researched,among which the influence law of the structural parameters on the instantaneous input energy spectrum are analyzed.The results show that the friction coefficient of isolation layer has a very great influence on the instantaneous input energy.The spectral curves of the instantaneous input energy for different the natural period are very close when the friction coefficient of isolation layer is very small,and the instantaneous input energy has a great value when the friction coefficient is very great.