scholarly journals A Study on the Sloshing Problem of Vertical Storage Tanks under the Action of Near-Fault Earthquakes

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Lijian Zhou ◽  
Tian Xu ◽  
Zhaohong Lu ◽  
Dong Zhang
Keyword(s):  
Wave Height ◽  
Storage Tank ◽  
Small Sample Size ◽  
Ground Motions ◽  
Reference Value ◽  
Small Sample ◽  
Storage Tanks ◽  
Near Fault ◽  
Practical Engineering ◽  
Near Fault Earthquakes

In this study, through a vibration table test, finite element simulation, and research on the rationality of the wave-height fortification of national storage tank specifications, the sloshing response of vertical storage tanks under the action of near-fault ground motion was analyzed. The test results showed that the sloshing wave height of a vertical storage tank was larger under near-fault or long-period ground motions, and the relationship between the sloshing wave height and the peak acceleration of input ground motions was approximately linear. The numerical simulations of the model tank showed that the simulation wave height and the test wave-height data were well fitted. Therefore, it was feasible to simulate the sloshing of large vertical storage tanks using ADINA software. In addition, a large number of sloshing simulations of near-fault ground motions on 10,000 m3 vertical storage tanks were performed. The simulated wave height had a high correlation with the predominant period or pulse period of near-fault ground motions. Under the calculation with similar parameters, the wave height of the tank standard in several countries had a lower fortification of the near-fault excitation wave height. Through the root mean-square method using a small sample size, a wave-height correction under a near-fault effect was applied to the wave-height formula for the Chinese tank seismic specification. Finally, the problem of a double-damping correction was addressed by adjusting China’s GB50341 wave-height formula. This work provides a reference value for practical engineering applications.

Performance of bi-directional elliptical rolling rods for base isolation of buildings under near-fault earthquakes

2017 ◽  
Vol 21 (5) ◽  
pp. 675-693 ◽  
Author(s):  
Aruna Rawat ◽  
Naseef Ummer ◽  
Vasant Matsagar
Keyword(s):  
Base Isolation ◽  
Ground Motions ◽  
Frictional Resistance ◽  
Curved Surface ◽  
Isolation System ◽  
Near Fault ◽  
Earthquake Ground Motions ◽  
Base Isolation System ◽  
Near Fault Earthquakes ◽  
Storey Building

Rolling base isolation system provides effective isolation to the structures from seismic base excitations by virtue of its low frictional resistance. Herein, dynamic analysis of flexible-shear type multi-storey building mounted on orthogonally placed elliptical rolling rod base isolation systems subjected to bi-directional components of near-fault earthquake ground motions is presented. The orthogonally placed rods would make it possible to resist the earthquake forces induced in the structure in both the horizontal directions. The curved surface of these elliptical rods has a self-restoring capability due to which the magnitude of peak isolator displacement and residual displacement is reduced. The roughness of the tempered curved surface of the rollers dissipates energy in motion due to frictional damping. The seismic performance of the multi-storey building mounted on the elliptical rolling rod base isolation system is compared with that mounted on the sliding pure-friction and cylindrical rolling rod systems. Parametric studies are conducted to examine the behavior of the building for different superstructure flexibilities, eccentricities of the elliptical rod, and coefficients of friction. It is concluded that the elliptical rolling rod base isolation system is effective in mitigation of damaging effects of the near-fault earthquake ground motions in the multi-storey buildings. Even under the near-fault earthquake ground motions, the base-isolated building mounted on the elliptical rolling rods shows considerable reduction in seismic response. The isolator displacement with the elliptical rolling rod base isolation system is less in comparison to the pure-friction and cylindrical rolling rod systems.

Earthquake Proof Efficiency of Sliding Base Isolator With Dog-Bone Type Damping

2005 ◽  
Author(s):  
C. S. Tsai ◽  
Tsu-Cheng Chiang ◽  
Bo-Jen Chen
Keyword(s):  
Ground Motions ◽  
Active Faults ◽  
Friction Behavior ◽  
Near Fault ◽  
The Past ◽  
Numerical Studies ◽  
Dog Bone ◽  
Base Isolator ◽  
Near Fault Earthquakes ◽  
Base Isolators

In recent years, there have been more and more seismic retrofit applications of using base isolators in seismic prone regions. In the past, the focuses of researches on the efficiency of various base isolators have been aimed at their behavior under earthquakes without long predominant periods. The doubts of efficiency of the base isolator nearby active faults or located at a soft deposit soil have been raised by researchers. It is revealed from previous studies that the seismic responses of the base isolated structure are significant due to the influence of resonance. In order to minimize the inherent shortcomings of base isolators, various base isolators with dog bone type of friction behavior have been proposed in this study. In the meanwhile, the exact solutions used to describe the behavior of the proposed isolators have also been derived in this study. The numerical studies show that the displacement responses of proposed isolators under near fault earthquakes and ground motions with long predominant periods are much lower than those of the traditional FPS and VCFPS devices. Hence, the required dimensions of proposed isolators can be smaller than those for the FPS and VCFPS isolators.

Parametric study of stochastic seismic responses of base-isolated liquid storage tanks under near-fault and far-fault ground motions

2016 ◽  
Vol 24 (24) ◽  
pp. 5747-5764 ◽  
Author(s):  
Sina Safari ◽  
Reza Tarinejad
Keyword(s):  
Base Isolation ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Characteristic Parameter ◽  
Statistical Linearization ◽  
Storage Tanks ◽  
Earthquake Excitation ◽  
Isolation System ◽  
Near Fault ◽  
Liquid Storage

Seismic response of base isolated steel liquid storage tanks is investigated in this study by a stochastic approach in frequency domain. For the purpose of evaluating different frequency contents of seismic events on the responses of fixed and isolated tanks, the earthquake excitation is characterized by power spectral density function. Since earthquake is a random process, stochastic seismic analysis is used and root mean square response predicts behavior of system properly. Two types of isolation system are assumed and nonlinear behavior of base isolation systems are developed by an iterative statistical linearization scheme. The study demonstrates the influence of each characteristic parameter of the storage tanks and isolation system and also excitation features. It is confirmed that near-fault earthquake excitations amplify the overall response of the system. Base isolation is known as an effective technique to reduce responses appropriately. It is demonstrated that the sloshing responses of the tanks is significantly reduced by sliding bearing. Further, excitation parameters, PGV/PGA ratio of records and pulse period in near-fault ground motions, that represent differences in two sets of earthquakes are defined to recognize variation of responses.

scholarly journals SLE Single-Step Purification and HPLC Isolation Method for Sterols and Triterpenic Dialcohols Analysis from Olive Oil

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2019
Author(s):  
Manuel León-Camacho ◽  
María del Carmen Pérez-Camino
Keyword(s):  
High Performance ◽  
Small Sample Size ◽  
Reference Value ◽  
Fats And Oils ◽  
Single Step ◽  
Small Sample ◽  
Analytical Control ◽  
Unsaponifiable Fraction ◽  
Time Saving ◽  
Relative Standard

The unsaponifiable fraction of oils and fats constitutes a very small fraction but it is an essential part of the healthy properties of some specific oils. It is a complex fraction formed by a large number of minor compounds and it is a source of information to characterize and authenticate the oil sample. Specially, the composition of sterols of any oil or fat is a distinctive feature of itself and, therefore, it has become a useful tool for detecting contaminants and adulterants in oils. A new supported liquid extraction (SLE) technique for the analysis and characterization of the unsaponifiable fraction of fats and oils is proposed. The SLE system includes, as a stationary phase, a combination of adsorbent materials which allow a highly purified unsaponifiable matter ready to be isolated by high performance liquid chromatography (HPLC) and quantified by gas chromatography (GC). This method ensures the removal of fatty acids, avoiding possible interferences and making the analysis of sterols and triterpenic dialcohols easier. The procedure uses a small sample size (0.2 g), reduces the volume of solvents and reagents, and reduces the handling of samples subjected to analytical control. All this is achieved without losing either precision—a relative standard deviation of each compound lower than the reference value (≤16.4%)—or recovery, being for all compounds higher than 88.00%. Therefore, this new technique represents a significant economic and time saving in business control laboratories, a larger productivity and enhancement of working safety.

Rehabilitation of steel concentrically braced frames with rocking cores for improved performance under near-fault ground motions

2016 ◽  
Vol 20 (6) ◽  
pp. 940-952 ◽  
Author(s):  
Bing Qu ◽  
Francisco Sanchez-Zamora ◽  
Michael Pollino ◽  
Hetao Hou
Keyword(s):  
Ground Motions ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
Braced Frame ◽  
Near Fault ◽  
Modal Properties ◽  
Concentrically Braced Frame ◽  
Core Technology ◽  
Concentrically Braced ◽  
Near Fault Earthquakes

This article focuses on evaluating the adequacy of a seismic rehabilitation technology which adds rocking cores to deficient steel concentrically braced frames in near-fault regions. Two demonstration buildings were rehabilitated with the technology. Seismic performance of the rehabilitated buildings was evaluated through numerical simulations. Analysis results suggest that the code-compliant concentrically braced frames may be vulnerable to collapse under the fault-normal components of the near-fault ground motions, approximately having a probability of exceedance of 10% in 50 years. It is found that the Rocking Core technology is effective in reducing the inter-story drift responses of the demonstration buildings under near-fault earthquakes. The rehabilitated systems can further benefit from the use of hysteretic energy dissipating links between the rocking cores and existing concentrically braced frames. This article also addresses the influence of the rocking cores on modal properties of the rehabilitated buildings. It is found that the rocking core with moderate stiffness does not significantly alter the modal properties of a rehabilitated concentrically braced frame.

Seismic response of base isolated liquid storage tanks to real and simulated near fault pulse type ground motions

2018 ◽  
Vol 112 ◽  
pp. 58-68 ◽  
Author(s):  
Eren Uckan ◽  
Önder Umut ◽  
Fatma Nurten Sisman ◽  
Shaghayegh Karimzadeh ◽  
Aysegul Askan
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
Storage Tanks ◽  
Near Fault ◽  
Liquid Storage ◽  
Pulse Type

The Vertical and Horizontal Spectra of Near-Fault Ground Motions

2012 ◽  
Vol 204-208 ◽  
pp. 3335-3339
Author(s):  
Jiang Yin ◽  
Xian Yan Zhou ◽  
Guo Jing He
Keyword(s):  
Ground Motions ◽  
Response Spectra ◽  
Vertical Acceleration ◽  
Period Range ◽  
Seismic Reliability ◽  
Design Spectrum ◽  
Near Fault ◽  
Seismic Design Code ◽  
Short Period ◽  
Near Fault Earthquakes

Based on the horizontal and vertical components of a set of 30 acceleration records obtained from 10 near-fault earthquakes, the horizontal and the vertical response spectra are established, and have been compared with each other in this study. Statistical analyses show that, for the selected 30 acceleration records, the maximum mean of vertical acceleration spectra is slightly higher than which of horizontal acceleration spectra. That means the near-fault earthquake really have significant vertical effect. Consulting the domestic and international research achievement, the normalized near-fault design spectrum adapted to Chinese seismic design Code (GB50011-2010) is established in horizontal direction. The results show that, within short period range, the horizontal near-fault design spectrum obtained in this paper is obviously higher than which derived from Chinese seismic code. Subsequently, the spectra of horizontal components for the selected 30 records are each scaled to match the horizontal near-fault design spectrum at two periodic points of 1.0 and 1.5 sec respectively, and the corresponding vertical spectra are scaled with the horizontal spectra at the same time. The scaled results reveal that the vertical spectra have much higher discretion than horizontal spectra, hence the study in this paper could initiates the research interest to a new aspect concerned with the randomness of vertical spectra for near-fault ground motions, which would affect the seismic reliability of structures significantly.

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