Seismic Isolation Analysis on Long-Span Platform Bridge Connecting Twin-Tower Structures

2011 ◽  
Vol 255-260 ◽  
pp. 1225-1229
Author(s):  
Huang Sheng Sun ◽  
Li Nuo Cheng ◽  
Shi Hai Chen
Keyword(s):  
Seismic Isolation ◽  
Seismic Responses ◽  
One Pot ◽  
Isolation System ◽  
High Position ◽  
Long Span ◽  
Steel Truss ◽  
Story Drift ◽  
Isolation Systems ◽  
Rubber Bearings

In order to mitigate the seismic response of twin-tower structure linked by a steel truss platform bridge, as well as to reduce temperature force in the steel truss, eight groups of combined isolation system, each consisting of one pot-type bearing and four rubber bearings, were designed to connect the upper platform bridge to the lower supporting reinforced concrete towers. The features and working principles of the high-position isolation system were described. Then the seismic responses, including displacement, story drift and floor acceleration, of the structure with the isolation systems were calculated and compared with those of the structure with hinge joints in lieu of isolation. It is found that both the structural seismic responses and the temperature forces in the large-span mega-truss structure can be reduced by the high-position isolation system.

scholarly journals Comparing Rubber Bearings and Eradi-Quake System for Seismic Isolation of Bridges

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5247
Author(s):  
Chang Beck Cho ◽  
Young Jin Kim ◽  
Won Jong Chin ◽  
Jin-Young Lee
Keyword(s):  
Seismic Isolation ◽  
New Technology ◽  
Isolation System ◽  
Seismic Safety ◽  
Response Characteristics ◽  
Rubber Bearing ◽  
Seismic Force ◽  
Isolation Systems ◽  
Rubber Bearings ◽  
Seismic Isolation Systems

Seismic isolation systems have been used worldwide in bridge structures to reduce vibration and avoid collapse. The seismic isolator, damper, and Shock Transmission Unit (SUT) are generally adopted in the seismic design of bridges to improve their seismic safety with economic efficiency. There are several seismic isolation systems, such as Natural Rubber Bearing (NRB), Lead Rubber Bearing (LRB), and the Eradi-Quake System (EQS). EQS as a new technology is expected to effectively reduce both seismic force and displacement, but there is still some need to verify whether it might provide an economical and practical strategy for a bridge isolation system. Moreover, it is important to guarantee consistent performance of the isolators by quality control. A comparative evaluation of the basic properties of the available seismic isolators is thus necessary to achieve a balance between cost-effectiveness and the desired performance of the bridge subjected to extreme loading. Accordingly, in this study, the seismic response characteristics of the seismic isolation systems for bridges were investigated by conducting compressive test and compressive-shear test on NRB, LRB, and EQS.

Research and Development of Three Dimensional Seismic Isolation System Utilized Coned-Disc-Springs With Rubber Bearings

2017 ◽  
Author(s):  
Takayuki Miyagawa ◽  
Tomoyoshi Watakabe ◽  
Tomohiko Yamamoto ◽  
Tsuyoshi Fukasawa ◽  
Shigeki Okamura
Keyword(s):  
Seismic Isolation ◽  
Three Dimensional ◽  
Safety Margin ◽  
Seismic Load ◽  
Isolation System ◽  
Seismic Safety ◽  
Track Record ◽  
Rocking Motion ◽  
Isolation Systems ◽  
Rubber Bearings

The seismic isolation system consisting of laminated rubber bearings is applied to development of the Sodium-cooled Fast Reactor (SFR) in Japan. While rubber bearings as horizontal isolation system have been expected to be ensured seismic safety margin of components installed in reactor building against horizontal seismic load, vertical isolation systems have been also studied in order to tolerate to the seismic load which has been increased steadily. In this paper, the three dimensional seismic isolation system by combining coned disc springs with rubber bearings is proposed as a concept which consists of isolation devices with abundant track record. Analytical study for this system results that the rocking motion can be suppressed by itself without any suppression system and that the mitigation of vertical response can be enough for buckling design of the reactor vessel simultaneously. In particular, it is important that the vertical natural frequency of system is within the range of 3Hz to 5Hz. Besides, layout, size and stacks of coned discs in the unit of system are studied in order to obtain suitable for specification to SFR buildings.

Required Properties of Seismic Isolation System for Nuclear Power Plants

2010 ◽  
Author(s):  
Satoshi Fujita ◽  
Keisuke Minagawa ◽  
Takeshi Kodaira
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Three Dimensional ◽  
Isolation System ◽  
Seismic Safety ◽  
Isolation Systems ◽  
Rubber Bearings ◽  
Seismic Isolation Systems

In Japan, applications of seismic isolation systems to new generation nuclear power plants and fast breeder reactors have been expected in order to enhance seismic safety. However there are lots of restrictions for design of isolation systems, such as strong design seismic wave, deformation of piping between an isolated structure and a non-isolated structure, and so on. In addition combination of horizontal and vertical isolation has possibility to cause rocking motion if a three-dimensional isolation system is applied. Therefore isolation systems should be designed properly. Moreover the design of seismic isolation system has to consider influence on inner equipment and piping. This paper describes investigation regarding required properties and performance of seismic isolation system for nuclear power plants. The investigation is carried out by numerical analysis. In the analysis, various isolation devices such as friction pendulum bearings and so on are applied as well as natural rubber bearings.

Development of Seismic Isolation Systems for Sodium-Cooled Fast Reactors in Japan

2016 ◽  
Author(s):  
Nobuchika Kawasaki ◽  
Tomoyoshi Watakabe ◽  
Takashi Wakai ◽  
Tomohiko Yamamoto ◽  
Tsuyoshi Fukasawa ◽  
...  
Keyword(s):  
Natural Frequency ◽  
Seismic Isolation ◽  
Reactor Core ◽  
Fast Reactors ◽  
Isolation System ◽  
Static Tests ◽  
Isolation Systems ◽  
Rubber Bearings ◽  
Seismic Isolation Systems ◽  
Suppression System

Sodium-cooled Fast Reactors (SFRs) have components with thinner walls as compared with light water reactors, although Japan is an earthquake-prone country. Thus, seismic isolation systems have been conventionally employed in SFR system design to reduce seismic forces on the systems in Japan. Implementation of seismic design in the reactor core and buckling design in the reactor vessel requires 8 Hz (or less) vertical frequency’s isolation system being applied. This paper introduces three isolation concepts to achieve the frequency. The isolation systems, which enable vertical 8 Hz natural frequency, comprise thicker laminated rubber bearings (TRBs). By combining coned disk springs with TRBs, vertical natural frequency is in a range from roughly 3 Hz to 5 Hz. Combining pneumatic springs to RBs and adding the rocking suppression system, vertical natural frequency becomes under 1 Hz. All isolation systems need horizontal damping like oil dampers. A vertical 8 Hz isolation system with TRBs and oil dampers is under development in Japan as a principal isolation concept. This system was selected because of its simple configuration and fewer issues to be resolved in the development. Since TRBs and oil dampers are basic isolation elements, they can be applied to other isolation systems. The response acceleration of 5 Hz vertical isolation is 50% of that of 8 Hz based on the analytical survey. A series of static tests of coned disk springs was carried out to confirm design equations. Based on these knowledge, 5 Hz vertical isolation system with TRBs and the coned disk springs can be designed. The response acceleration of 1 Hz vertical isolation is 10% of that of 8 Hz. A rocking suppression system was studied in the past, and the further simplification of this system is the largest challenge for this concept. These three isolation concepts are isolation candidates for SFRs in Japan. To obtain enough seismic margins for each plant site, these isolation systems need to be developed.

scholarly journals Seismic isolation system of two hinged arch suspended-deck bridge: a case study on Kalikuto bridge - Indonesia

2020 ◽  
Vol 156 ◽  
pp. 05024
Author(s):  
Tri Suryadi ◽  
Arvila Delitriana ◽  
Zdenek Fukar ◽  
Rusri Tjendana
Keyword(s):  
Seismic Isolation ◽  
Performance Tests ◽  
Isolation System ◽  
Expansion Joints ◽  
Lead Rubber Bearings ◽  
Design Requirements ◽  
Isolation Systems ◽  
Rubber Bearings ◽  
Seismic Isolation Systems

Seismic isolation systems are widely used in buildings, bridges, and industrial structures all over the world. The system is known for the efficiency to reduce earthquake demand and thus provide better seismic performance of the structures. In particular to application in an arch suspended-deck bridge, seismic isolation system can be a solution for the seismic resisting system due to the incapability of the cable hangers to transfer horizontal forces from excitation mass on the hanging deck to the main compression arches. Kalikuto arch bridge that is built in 2018 has implemented both Lead Rubber Bearings and Seismic Rubber Expansion Joints as the part of its seismic resisting system. These two seismic isolation devices were designed and engineered accurately to fulfil the seismic design requirements of the Kalikuto bridge. Finally, several performance tests were conducted to evaluate the design compliance of the manufactured devices.

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.

Fundamental Study on the Super-Long-Period Active Isolation System

2004 ◽  
Author(s):  
Keisuke Minagawa ◽  
Satoshi Fujita
Keyword(s):  
Control System ◽  
Seismic Isolation ◽  
Seismic Waves ◽  
Model Matching ◽  
Fundamental Study ◽  
Natural Period ◽  
Isolation System ◽  
Long Period ◽  
Rubber Bearings ◽  
Classical Control

Since the Hanshin-Awaji Earthquake Disaster, the number of isolated structures has been greatly increased. The natural period of the isolation system is designed around 3 seconds, because predominate period of observed seismic waves is usually 0.1 to 1 second. However, relatively long period seismic waves have been observed in various earthquakes, and the resonance of long-period structures, such as high-rise buildings, during earthquakes have been reported at the same time. Therefore the natural period needs to be extended. When extending the natural period of the isolated structure using rubber bearings, its stiffness needs to be reduced. It is more difficult to extend the natural period of the isolation system than the conventional system because of its buckling problem. Therefore we propose a super-long-period active seismic isolation system as a new method for extending the natural period of the isolated structure. This system consists of rubber bearings and actuators. In this study, we designed a control system by using the model-matching-method. This is one of the classical control system design methods. We investigated the isolation performance by numerical analysis. In addition, we selected the optimal variables of transfer function using genetic algorithm.

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.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 3 — Seismic Response of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Akihito Otani ◽  
Teruyoshi Otoyo ◽  
Hideo Hirai ◽  
Hirohide Iiizumi ◽  
Hiroshi Shimizu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

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