Influence of the Strain Hardening of HDRBs in the Evaluation of the Seismic Response of a RC Base Isolated Structure

2012 ◽  
Vol 602-604 ◽  
pp. 1546-1554
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis ◽  
Mario Pasquino
Keyword(s):  
Strain Hardening ◽  
Seismic Response ◽  
Base Isolation ◽  
Cyclic Behavior ◽  
Hysteretic Model ◽  
Isolation System ◽  
Limit Value ◽  
Hardening Effect ◽  
Base Isolation System ◽  
Rubber Bearings

In this paper we have analyzed the influence of the strain hardening behavior of High Damping Rubber Bearings (HDRBs) adopted for a base isolation system of a Reinforced Concrete (RC) isolated structure. For the modeling of the rubber isolators we have adopted an evolution of the Bouc-Wen’s hysteretic model taking into account the incremental hardening effect which appears when the shear strain of the HDRB exceeds the limit value around 100% usually adopted in design practice. The incremental hardening effect is sometimes neglected in the design but it is an important aspect because it ensures a seismic protection of the base isolated structure also in presence of exceptional seismic events for intensity or frequency content. In this paper we have highlighted the significant influence of this phenomenon in the seismic response of the isolated structure by reporting the cyclic behavior of a HDRB respectively neglecting and considering this aspect.

Seismic Analysis and Comparison of Different Base Isolation Systems for a Multi-Storey RC Building with Irregularities in Plan

2012 ◽  
Vol 594-597 ◽  
pp. 1788-1799 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis
Keyword(s):  
Base Isolation ◽  
Seismic Analysis ◽  
Cyclic Behavior ◽  
Isolation System ◽  
High Damping Rubber Bearings ◽  
Fixed Base ◽  
Base Isolation System ◽  
High Damping Rubber ◽  
Isolation Systems ◽  
Rubber Bearings

In the present paper the dynamic nonlinear analysis for a 3D base isolated structure is illustrated. A base isolated reinforced concrete building is designed and verified according to the European seismic codes such that the superstructure remains almost completely elastic and the nonlinear elements are localized only in the base isolation system. Nonlinear hysteretic models have been adopted to reproduce the cyclic behavior of the isolators. Two different base isolation systems are considered and their performances are compared for evaluating the behaviour of a base isolated building, highly irregular in plan, in presence of a seismic excitation defined with recorded accelerograms which characterize the bi-directional ground motions. The isolation system has been realized with a combination in parallel of elastomeric bearings and sliding devices. In the first analyzed isolation system we have used the High Damping Rubber Bearings (HDRB) and in the second analyzed isolation system we have used the Lead Rubber Bearings (LRB). Finally a comparative analysis between the base isolated structure with hybrid base isolation systems and the conventional fixed base structure is detailed.

Research on the Effect of Combined Seismic Isolation System

2012 ◽  
Vol 446-449 ◽  
pp. 3299-3303
Author(s):  
Xi Sen Fan ◽  
Ting Lei Tian
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Seismic Responses ◽  
Combined System ◽  
Isolation System ◽  
Lead Rubber Bearings ◽  
Base Isolation System ◽  
Rubber Bearings ◽  
The Relationship

The isolation system between the upper structure and the foundation could reduce the seismic response of the former. A system combined of sliding and lead rubber bearings (LRB) is more effective in seismic isolation than using the later alone. In this research, the seismic responses of a building which was set with LRB and a combined system (the proportions between the sliding and LRB were 1/6, 1/4 and 1/3) respectively were analyzed and compared to that of the building without base isolation system to investigate the effect of seismic isolation. The relationship between isolation coefficient and the proportion of bearings was studied. The results show that the combined system could reduce the seismic response of structure, and it is more effective in seismic isolation if the leading bearing is relatively more.

scholarly journals STRUCTURAL DESIGN OF HIGH-RISE BUILDING WITH BASE ISOLATION SYSTEM USING ELASTIC SLIDING BEARINGS AND RUBBER BEARINGS

2001 ◽  
Vol 7 (12) ◽  
pp. 99-104 ◽  
Author(s):  
Ichizo KAWABATA ◽  
Masaharu TAKAYAMA ◽  
Yasuhiro NISHIKAWA ◽  
Yuichi KIMURA ◽  
Eiichi YAMAZAKI ◽  
...  
Keyword(s):  
Structural Design ◽  
Base Isolation ◽  
Sliding Bearings ◽  
Isolation System ◽  
High Rise ◽  
High Rise Building ◽  
Base Isolation System ◽  
Rubber Bearings

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

2007 ◽  
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.

scholarly journals Research on Seismic Response of Base-Isolated Nuclear Island Building considering FSI Effect of PCS Water Tank

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chenning Song ◽  
Chao Wei ◽  
Zhi Zhang
Keyword(s):  
Seismic Response ◽  
Base Isolation ◽  
Numerical Models ◽  
Horizontal Displacement ◽  
Reduction Ratio ◽  
Isolation Effect ◽  
Water Tank ◽  
Isolation System ◽  
Base Isolation System ◽  
Natural Frequency Analysis

Base isolation can be used to reduce seismic response of structure and protect the structure from damage subjected to earthquake. To study the isolation effect of new PWR nuclear power plant with a base isolation system, considering FSI (fluid-structure interaction) effect by the simplified model, two 3D numerical models (one nonisolated model and one isolated model) were established. After natural frequency analysis, one artificial ground motion was chosen to analyze isolation effect qualitatively. Based on the results, the accelerations and relative displacements of nuclear island building under ten natural ground motions were statistically analyzed to evaluate the isolation effect quantitatively. The results show that the base isolation system can reduce the natural frequencies of nuclear island building. Horizontal accelerations can be reduced effectively, but the isolation effect is not obvious in vertical direction. The acceleration reduction ratio of the top is about 70%–90%, and the acceleration reduction ratio of the lower part is about 20%–60%. Horizontal displacement of the isolated model is far larger than that of the nonisolated model, and horizontal displacement will become larger considering FSI effect. These conclusions could provide some references for studies on the isolation system of nuclear island building.

Design of Shape Memory Alloy Damper for Base Isolated Structure

1997 ◽  
Author(s):  
Krzysztof Wilde ◽  
Paolo Gardoni ◽  
Yozo Fujino ◽  
Stefano Besseghini
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Base Isolation ◽  
Hysteretic Behavior ◽  
Isolation System ◽  
Rubber Bearing ◽  
Laminated Rubber Bearing ◽  
Base Isolation System ◽  
Rubber Bearings ◽  
Smart Base Isolation

Abstract Base isolation provides a very effective passive method of protecting the structure from the hazards of earthquakes. The proposed isolation system combines the laminated rubber bearing with the device made of shape memory alloy (SMA). The smart base isolation uses hysteretic behavior of SMA to increase the structural damping of the structure and utilizes the different responses of the SMA at different levels of strain to control the displacements of the base isolation system at various excitation levels. The performance of the smart base isolation is compared with the performance of isolation by laminated rubber bearings to assess the benefits of additional SMA damper for isolation of three story building.

21112 Vibration analysis of small base isolation system using friction bearings : Effects of eccentricity on seismic response

2013 ◽  
Vol 2013.19 (0) ◽  
pp. 519-520
Author(s):  
Katsumi Kurita ◽  
Shigeru Aoki ◽  
Yuji Nakanishi ◽  
Kazutoshi Tominaga ◽  
Mitsuo Kanazawa ◽  
...  
Keyword(s):  
Seismic Response ◽  
Vibration Analysis ◽  
Base Isolation ◽  
Isolation System ◽  
Base Isolation System ◽  
Small Base ◽  
Friction Bearings
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