Different numerical models for the hysteretic behaviour of HDRB 's on the dynamic response of base-isolated structures with lumped-mass models under seismic loading

摘要

The effect of seismic base isolation by HDRB's (High Damping Rubber Bearings) is based on two main effects. The one is the capability of large elastic deformations which increases the fundamental period of the structure and reduces the seismic response. The second effect is the non-elastic absorption of the energy introduced by the earthquake by means of the hysteretic damping. An adequate description of the nonlinear characteristic of the HDRB's and a correct modelling of the overall structure are presuppositions for a realistic estimation of the mechanism and effectivity of such a base isolation. Three different numerical approaches for the description of HDRB's have been developed, in order to show the influence on the results. The effect of these approaches on the dynamic response are studied with lumped-mass models representing a base-isolated storage tank for liquefied natural gas (LNG). The maximum accelerations of the isolated structure are compared, in order to verify the accuracy of the numerical approaches and the boundaries of their applicability.