Shaking Table Test of a Model Bridge with Sliding Type Base Isolation System.

Abstract Vibration isolation devices are generally applied to equipment that dislikes vibration installed in buildings. Since the vibration isolator is intended for small vibration input, the damage has been frequently confirmed with excessive vibration input such as an huge earthquake motion. Therefore, the development of a seismic isolation device with a vibration isolation function is desired for important equipment and expensive manufacturing equipment. However, the vibration region targeted by the vibration isolator and the vibration region of the seismic input are at completely different levels. In this study, the authors propose a seismic isolation system using air floating technique to cope with such different vibration levels. In this paper, basic concept, basic performance, preliminary performance evaluation by nonlinear time response analysis, and performance evaluation by shaking table test.

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Shaking Table Test Study on Mid-Story Isolation Structures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.378 ◽

2012 ◽

Vol 446-449 ◽

pp. 378-381

Author(s):

Jian Min Jin ◽

Ping Tan ◽

Fu Lin Zhou ◽

Yu Hong Ma ◽

Chao Yong Shen

Keyword(s):

Seismic Response ◽

Seismic Isolation ◽

Shaking Table Test ◽

Base Isolation ◽

Shaking Table ◽

Natural Period ◽

Isolation System ◽

Isolation Layer ◽

Lead Rubber Bearing ◽

Complex Structural

Mid-story isolation structure is developing from base isolation structures. As a complex structural system, the work mechanism of base isolation structure is not entirely appropriate for mid-story isolation structure, and the prolonging of structural natural period may not be able to decrease the seismic response of substructure and superstructure simultaneously. In this paper, for a four-story steel frame model, whose prototype first natural period is about 1s without seismic isolation design, the seismic responses and isolation effectiveness of mid-story isolation system with lead rubber bearing are studied experimentally by changing the location of isolation layer. Respectively, the locations of isolation layer are set at bottom of the first story, top of the first story, top of the second story and top of the third story. The results show that mid-story isolation can reduce seismic response in general, and substructure acceleration may be amplified.

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Polymeric Bearings as a new base isolation system suitable for mitigating machine-induced vibrations

MATEC Web of Conferences ◽

10.1051/matecconf/201821117001 ◽

2018 ◽

Vol 211 ◽

pp. 17001 ◽

Cited By ~ 1

Author(s):

Tomasz Falborski ◽

Robert Jankowski

Keyword(s):

Base Isolation ◽

Excitation Frequency ◽

Hysteresis Loops ◽

Shaking Table ◽

Damping Properties ◽

Structural Vibrations ◽

Isolation System ◽

Equivalent Damping ◽

Flexible Polymer ◽

Base Isolation System

The present paper summarizes the preliminary results of the experimental shaking table investigation conducted in order to verify the effectiveness of a new base isolation system consisting of Polymeric Bearings in reducing strong horizontal machine-induced vibrations. Polymeric Bearing considered in the present study is a prototype base isolation system, which was constructed with the use of a specially prepared flexible polymer with improved damping properties. Dynamic oscillatory tests, during which a concrete base slab supported by four Polymeric Bearings was subjected to horizonal sinusoidal excitations characterized by different frequencies and amplitudes, were conducted in order to determine the damping properties of Polymeric Bearings and their effectiveness in mitigating structural vibrations. Equivalent damping ratios for every excitation frequency considered were determined using the experimentally obtained hysteresis loops. Final conclusions are presented and the results discussed.

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Reduction of Seismic Response of Mechanical System by Base Isolation System With Friction Bearing

Volume 8: Seismic Engineering ◽

10.1115/pvp2007-26302 ◽

2007 ◽

Cited By ~ 1

Author(s):

Shigeru Aoki ◽

Yuji Nakanishi ◽

Kazutoshi Tominaga ◽

Takeshi Otaka ◽

Tadashi Nishimura ◽

...

Keyword(s):

Mechanical System ◽

Seismic Response ◽

Base Isolation ◽

Low Frequency ◽

Simulation Method ◽

Shaking Table ◽

Restoring Force ◽

Isolation System ◽

Friction Bearing ◽

Base Isolation System

Reduction of seismic response of mechanical system is important problem for aseismic design. Some types of base isolation systems are developed and used in actual base of buildings and floors in buildings for reduction of seismic response of mechanincal system. In this paper, a base isolation system utilizing bearing with friction and restoring force of bearing is proposed. Friction bearing consists of two plates having spherical concaves and oval type metal or spherical metal with rubber. First, effectiveness of the base isolation system is examined experimentally. Using artificial time histories, the isolated table is shaken on the shaking table. The maximum value of response is reduced and sum of squares of response is significantly reduced. Power spectrum is significantly reduced in almost of all frequency regions, except for very low frequency region. Next, in order to examine reduction of seismic response of actual mechanical system, a console rack is set on the isolated plate. Seismic response is also significantly reduced. Finally, obtained results of experiment are examined by simulation method. An analytical model considering friction and restoring force is used. From simulation method, effectiveness of the proposed base isolation system is demonstrated.

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Experimental Investigation on Semi-Active Control of Base Isolation System Using Magnetorheological Dampers for Concrete Frame Structure

Applied Sciences ◽

10.3390/app9183866 ◽

2019 ◽

Vol 9 (18) ◽

pp. 3866 ◽

Cited By ~ 9

Author(s):

Weiqing Fu ◽

Chunwei Zhang ◽

Mao Li ◽

Cunkun Duan

Keyword(s):

Optimal Control ◽

Control System ◽

Active Control ◽

Shaking Table Test ◽

Base Isolation ◽

Mr Damper ◽

Shaking Table ◽

Engineering Practice ◽

Isolation System ◽

Large Earthquakes

The traditional passive base isolation is the most widely used method in the engineering practice for structural control, however, it has the shortcoming that the optimal control frequency band is significantly limited and narrow. For the seismic isolation system designed specifically for large earthquakes, the structural acceleration response may be enlarged under small earthquakes. If the design requirements under small earthquakes are satisfied, the deformation in the isolation layer may become too large to be accepted. Occasionally, it may be destroyed under large earthquakes. In the isolation control system combined with rubber bearing and magnetorheological (MR) damper, the MR damper can provide instantaneous variable damping force to effectively control the structural response at different input magnitudes. In this paper, the control effect of semi-active control and quasi-passive control for the isolation control system is verified by the shaking table test. In regard to semi-active control, the linear quadratic regulator (LQR) classical linear optimal control algorithm by continuous control and switch control strategies are used to control the structural vibration response. Numerical simulation analysis and shaking table test results indicate that isolation control system can effectively overcome the shortcoming due to narrow optimum control band of the passive isolation system, and thus to provide optimal control for different seismic excitations in a wider frequency range. It shows that, even under super large earthquakes, the structure still exhibits the ability to maintain overall stability performance.

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