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Experimental study of base isolation by free rolling rods
Author(s) -
Lin TsungWu,
Chern ChingChurn,
Hone ChaoChi
Publication year - 1995
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290241207
Subject(s) - earthquake shaking table , displacement (psychology) , structural engineering , rod , superstructure , base (topology) , basement , geology , base isolation , angular displacement , geotechnical engineering , mechanics , engineering , geometry , physics , mathematics , mathematical analysis , reduction (mathematics) , medicine , psychology , civil engineering , alternative medicine , pathology , psychotherapist
Experimental and analytical studies of base isolation by free rolling rods under basement are described in this paper. The tests of the system, a one‐storey, 326‐kg structure mounted on a set of free rolling rods, is carried out on a 3 m × 3 m shaking‐table. The dynamic behaviour of the isolated structure is studied and used to verify the analytical results. In the isolation system, the coefficient of kinetic rolling friction, measured at different angular velocities, ranges from 0·0007 to 0·0016. The coefficients are reduced by decreasing the angular velocities. Two earthquakes, a short‐period and a long‐period motion in Taiwan, are utilized as the input signals. The accelerations experienced by the superstructure are decreased by factors of 56 and 60 in comparison with the fixed‐base condition for the two input earthquakes. Also, for each test, the peak relative‐to‐ground displacement of the basement is nearly equal to the peak ground displacement, and the permanent displacement of the basement is present after the end of the earthquake. Finally, tests of the system with a recentring‐force device is undertaken, where a soft spring added to the basement reduces efficiently the permanent displacement. Comparisons show a good agreement between experimental and theoretical results.