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each member along or adjacent to the x-axis to which the axial stresses due to the gravity load are
added. It is again observed that the axial stresses of the members of the non-isolated dome are reduced
drastically by introducing the base-isolation system.
Fig. 4.5 shows the hysteresis behavior of the base isolation system. It can be understood that the
present isolation system with sliding mechanism absorbs vibration energies by hysteretic damping.
The maximum displacement of the base isolation device remains within 17cm (130% of the height of
isolators) which may be considered allowable. The residual displacement of the base isolation device
at the termination of the earthquake remains within 2.4cm due to the effect of laminated rubber
isolators giving restoring forces after sliding.
It can be concluded from the above results that the proposed seismic isolation system is effective in
reducing the dome response under strong earthquake motions.
CONCLUSION
A seismic isolation system with sliding mechanism was proposed for reducing the seismic response of
large-span spatial structures. The proposed isolation system is a combination of elastic sliding devices
with commonly used laminated rubber isolators to give restoring forces after sliding. In order to
confirm its effectiveness in reducing the seismic response, shaking table tests were performed using a
small-scale arch model. The test results were utilized to validate the simulation method, which was
then applied to investigate the seismic response of a 200m span latticed dome supported by the baseisolation
system. The effectiveness of the proposed seismic isolation system was confirmed to reduce
the dome response under strong earthquake motions.
References
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