Study On RC Frame Storey Isolated Structure With Large Podium

Inter-story isolation technology is a passive control system,which is also a newseismic reduction technology developed recently. It could reduce the seismic responseof the structure, reduce the cost and bring down whipping effect of the high-risestructure,and used chiefly in which the base isolation technology not apply,such asoffshore architecture、the reinforcement of old biuldings and structure with largepodium. Inter-story isolation technology inherits and develops from base isolationtechnology, it offer structural engineer a new structure train of thought that could beselected and enrich the type of isolated structure. Compared with traditional aseismicplan and base isolation plan, the inter-story isolation plan have many advantages:constructing conveniently, lower construction cost and better economic and socialbenefit,and could easily receive the favour of structural engineer. Of all kinds ofinter-story isolation plans, isolated structure with large podium is most popular, itslower storey can be used as entertainment and recreational services,and the upperstorey,which have low commercial value, can be used as house.Through this research, the seismic reduction principle、mechanical property ofLRB、seismic dynamic characteristics of inter-story isolation structure with largepodium、the law of seismic response(absolute acceleration、storey shear and relativestorey displacement) and the seismic reduction effect of inter-story isolation structurewith large podium are exposited briefly.In contrast to the absolute max acceleration、storey shear and relative storey displacement of aseismic structure、inter-story isolationstructure with one and two isolation floors on the condition of slight earthquake andmegaseism, conclusion could be got as follows:the seismic response of inter-storyisolation structure is smaller than aseismic structure,and its seismic reduction effect isvery good; As the height (floor4)of the first isolation floor is fixed, while the secondisolation floors is fixed on the mid-height,its seismic reduction effect is the best, whilethe second isolation floors is fixed on the14floor, its seismic reduction effect is slightbetter, while the second isolation floors is fixed on the top floor floor,its seismicreduction effect is worst,but its seismic reduction effect is better than inter-storyisolation structure with one isolation floor, despite the effect is limited. Through thestudy on inter-story isolation structure with one isolation floor (floor4) on thecondition of slight earthquake,when the height of isolation floor is fixed,as the stiffness of isolation floor increase,the storey absolute max shear and relative storey maxdisplacement of the upper12floors increase first then reduce,at last tend towardsstability; The storey absolute max shear and relative storey max displacement of thelower3floors keep a slow growth first, then decline slowly after its value attain themaximum value,while its decrease rate is modest,at last the value increase slowly againand tend towards the aseismic structure. The influence rules of the storey absolute maxshear and relative storey max displacement of the whole structure according to dampingratio of isolation floor is relatively simple,its value decrease monotonously as thedamping ratio increase.This research contribute to the establishment of practical designmethod of inter-story isolation structure with large podium.