scholarly journals Seismic Vibration Control of Building with Lead Rubber Bearing Isolator

10.29007/pvzx ◽  
2018 ◽  
Author(s):  
Kishan Bhojani ◽  
Vishal Patel ◽  
Snehal Mevada

During the life span of structure there may be an effect of vibration. Due to vibration there may be major or minor damage in building. Base isolation is best method to reduce the seismic response of the structure. This paper gives idea about base isolation system which can be used in multi-story building to reduce seismic response of the structure. This paper represents the initialize study of dynamic parameter like effective damping for four earthquake time history. In this paper the optimum effective damping has been found out under the effect of Loma Prieta earthquake time history. The parametric study has been conducted to evaluate the effect on maximum displacement, maximum acceleration, maximum base shear in bare frame and frame with isolator.

2012 ◽  
Vol 256-259 ◽  
pp. 1117-1120
Author(s):  
Q. Rong

The optimization of second isolation period for parallel base isolation system is investigated systematically. The maximum dissipative energy scale factor is used as the objective function, the maximum sliding displacement of base-isolated layer, the residual displacement and the maximum base shear coefficient are considered as the constraining factors. For first to fourth category site, under the low amplitude severe earthquake, the variation rule of the four seismic response indicators for the second isolation period is approximately same, the second isolation period is proposed to be in the range of 4s to 6s.


2020 ◽  
Vol 10 (1) ◽  
pp. 45-54
Author(s):  
Soroush Kherad ◽  
Mahmood Hosseini ◽  
Mehrtash Motamedi

AbstractUsing seesaw structural system equipped with energy dissipating devices has been considered as a low-cost and low-tech way for creation of earthquake-resilient buildings. In this paper by considering three groups of multi-story buildings, including conventional buildings, LRB-based isolated buildings and building with seesaw structure, equipped with a newly introduced type of structural fuses, their seismic performances have been compared through nonlinear time history analyses (NLTHA). The employed fuses in seesaw buildings are a specific type of yielding plate dampers, called Multiple Curved Yielding Plate Energy Dissipater (MCYPED), installed at the bottom of the all circumferential columns of the lowest story of the building. To show the efficiency of the proposed seesaw system in comparison with other two mentioned groups, first, by finite element modeling, verified by experimental results, the initial and secondary stiffness values as well as the yielding and ultimate strengths of the MCYPEDs have been obtained to be modeled by multi-linear plastic springs in the seesaw buildings. Then, a series of NLTHA have been performed on the three groups of buildings by using a set of selected earthquakes. The compared responses include roof displacement and acceleration, base shear, inter-story drift and finally plastic hinges (PHs) formed in the building’s structures. Results show that the proposed seesaw building equipped with MCYPEDs not only results in lower seismic demand, similar to base isolation system, but also leads to remarkable energy dissipation capacity in the building structure at base level, so that the building structure remains basically elastic, and does not need any major repair work, even after large earthquakes, contrary to the conventional building which need to be demolished after the earthquake.


2012 ◽  
Vol 234 ◽  
pp. 96-101 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis

In the present work we have analyzed a particular base isolation system for the seismic protection of a multi-storey reinforced concrete (RC) building. The viscous dampers and friction sliders are the devices adopted in parallel for realizing the base isolation system. The base isolation structure has been designed and verified according to European seismic code EC8 and by considering for the friction sliders the influence of the sliding velocity on the value of the friction coefficient. A dynamic nonlinear analysis for a three-dimensional base isolated structure has been performed. Recorded accelerograms for bi-directional ground motions have been used which comply with the requirements imposed by EC8 for the representation of a seismic action in a time history analysis. In this paper a comparative analysis is presented between the base isolated structure with the described hybrid base isolation system and the traditional fixed base structure.


Author(s):  
Shigeru Aoki ◽  
Yuji Nakanishi ◽  
Kazutoshi Tominaga ◽  
Takeshi Otaka ◽  
Tadashi Nishimura ◽  
...  

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chenning Song ◽  
Chao Wei ◽  
Zhi Zhang

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.


2011 ◽  
Vol 11 (06) ◽  
pp. 1201-1228 ◽  
Author(s):  
AJAY SHARMA ◽  
R. S. JANGID

The influence of high initial isolator stiffness on the response of a base-isolated benchmark building is investigated. The base-isolated building is modeled as a three-dimensional linear-elastic structure having three degrees-of-freedom at each floor level. The time-history analysis of this building is carried out by solving the governing equations of motion using Newmark-beta method along with an iterative predictor–corrector approach. The force–deformation behavior of the isolation system is modeled by a bilinear law, which can be effectively used to model all isolation systems in practice. Three near-field earthquakes with bidirectional ground motions are considered. Structural response parameters such as absolute top floor acceleration, base shear, and base displacement are chosen for investigating the effects of high initial isolator stiffness. It was observed that the high initial isolator stiffness of the isolation system excites the higher modes in the base-isolated building and increases the top floor acceleration. Such a phenomenon can be detrimental to the sensitive instruments placed in the isolated structure. On the other hand, both the base displacement and base shear reduce marginally due to increase in the initial isolator stiffness. Further, the influences of high initial isolator stiffness are found to dependent on the period and characteristic strengths of the base isolation system.


2013 ◽  
Vol 2013.19 (0) ◽  
pp. 519-520
Author(s):  
Katsumi Kurita ◽  
Shigeru Aoki ◽  
Yuji Nakanishi ◽  
Kazutoshi Tominaga ◽  
Mitsuo Kanazawa ◽  
...  

2012 ◽  
Vol 602-604 ◽  
pp. 1546-1554
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis ◽  
Mario Pasquino

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.


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