Response of hybrid isolation system during a shake table experiment of a full‐scale isolated building |
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| Authors: | Keri L Ryan Taichiro Okazaki Camila B Coria Eiji Sato Tomohiro Sasaki |
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| Institution: | 1. Department of Civil and Environmental Engineering, University of Nevada, Reno, NV, USA;2. Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan;3. Dynamic Isolation Systems, Inc., McCarran, NV, USA;4. E‐Defense, National Research Institute for Earth Science and Disaster Prevention, Miki, Hyogo, Japan;5. Obayashi Corporation, Technical Research Institute, Kiyose, Tokyo, Japan |
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| Abstract: | A full‐scale 5‐story steel moment frame building was subjected to a series of earthquake excitations using the E‐Defense shake table in August, 2011. For one of the test configurations, the building was seismically isolated by a hybrid system of lead‐rubber bearings and low friction roller bearings known as cross‐linear bearings, and was designed for a very rare 100 000‐year return period earthquake at a Central and Eastern US soil site. The building was subject to 15 trials including sinusoidal input, recorded motions and simulated earthquakes, 2D and 3D input, and a range of intensities including some beyond the design basis level. The experimental program was one of the first system‐level full‐scale validations of seismic isolation and the first known full‐scale experiment of a hybrid isolation system incorporating lead‐rubber and low friction bearings. Stable response of the hybrid isolation system was demonstrated at displacement demands up to 550 mm and shear strain in excess of 200%. Torsional amplifications were within the new factor stipulated by the code provisions. Axial force was observed to transfer from the lead‐rubber bearings to the cross‐linear bearings at large displacements, and the force transfer at large displacements exceeded that predicted by basic calculations. The force transfer occurred primarily because of the flexural rigidity of the base diaphragm and the larger vertical stiffness of the cross‐linear bearings relative to the lead‐rubber bearings. |
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| Keywords: | cross‐linear bearings device load transfer full scale lead‐rubber bearings seismic isolation shaking table test |
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