Seismic Performance of Rocking Base-Isolated Structures Subjected To Biaxial Earthquake Loads


Abstract eng:
Literatures have showed that traditional sliding base-isolated systems may have long-period resonant-like response induced by a ground motion containing strong long-period frequency spectra. In this paper, a new type of isolator called variablefrequency rocking bearing is proposed. The system allows the bearing remain still under a moderate seismic load but start to rock back-and-forth during severe earthquakes. And the vibration is damped throughout each impact of the bearing on structural footing or foundation surfaces. Based on the force-displacement relation and analytical damping of the system, seismic response of the structure may be estimated through a modified elastic response spectrum. The objective of the paper is to investigate seismic performance of this base-isolated structure subjected to bi-axial earthquake loads. To validate proposed idea, a one-bay-one-story spaced structure base-isolated with rocking bearings was constructed. In total, 236 shaking table tests were conducted with various investigated parameters including aspect ratio of bearings, the shape of rocking plates (plane or polynomial), bi-directional earthquakes and waveforms of ground motion. Test results indicate that vibration behavior was nonlinear with respect to rocking amplitude. And structural response of the structure excited by bihorizontal earthquakes is the largest, followed by uni-axial and then bi-directional with horizontal plus vertical earthquakes. Due to the restrain of spring force at rocking interface, seismic response of structures excited by bi-directional with horizontal plus vertical earthquakes is found similar to those excited by uni-axial earthquakes. It is also found that seismic response is increased with the increase of aspect ratio of bearings, while the effect of rocking surface is marginal. Without any damage incurred under earthquakes, radiation damping of rocking systems is found less than 4% for all tests.

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Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
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Text je chráněný podle autorského zákona č. 121/2000 Sb.



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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 248.:
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