Analysis Of Height-to-Width Ratio For Sliding Base Isolation Structures

Sliding base isolation is a rapid-developed technology in recent years, and has a wide use and development all over the world. Sliding isolation is one of the basic styles of isolation, which separates the base with the super structure through the sliding floor; Lengthens the basic cycle of the structure, reduces the Earthquake response of the building by preventing seismic wave entering to the super structure. It has become a new trend of structure control and has been gained wide acknowledgement and use because of its advantages: such as Easy to operate, low cost, little influence of ground motion frequency characteristics and so on.This paper builds analytic model, of sliding isolation structure, establishes dynamic equation and sliding judge conditions under various conditions by doing dynamic analysis to sliding base isolation. Also, the writer did some Inferential reason to the propose of height-to-width ratio equation. slouted the Time interval equation based on Theoretical analysis and motorial equation. Using Parameters of Newmark-β:γ= 1/2,β= 1/4 and 3D- BASIS -TABS program for analytic the sliding isolation system,Determinate the factors which influence the height-to-width ratio: friction coefficientμ,damping ratioξstiffness of isolated floor, superstructure stiffness,isolation installation and so on. Besides, analyses the height-to-width ratio of compound isolation system structure, compared with dumped-sliding isolation structure.The results are as follows: with the increase of dump paraments, dumper of isolation level ,ground motion acceleration, ground motion intensity ,the stiffness of the isolation level, the height-to-width ratio become low; it will also change With th change of the bearing of seismic isolation collocation: with the reduce of the bearing number in width direction, the height-to-width ratio will increase; Besides, with the increase of spectrum characteristics, the peak acceleration, the height-to-width ratio will also reduce, but the speed is low. Sliding isolation system structure can do much better in increasing the height-to-width ratio and reducing the seismic overturning moment than basic structure system; compound isolation system and pure dump-sliding isolation system can also do this and the former can do it better than the latter. They can provide the references to the engineering design.