scholarly journals Comparison Between Two Types of Seismic Tests of Racking Systems

ce/papers ◽  
2021 ◽  
Vol 4 (2-4) ◽  
pp. 1992-1998
Author(s):  
Oriol Bové ◽  
Miquel Ferrer ◽  
Francesc López Almansa ◽  
Francesc Roure
Keyword(s):  
Seismic Tests

Physical and Numerical Simulations of the Seismic Response of a 1,100 kV Power Transformer Bushing

2018 ◽  
Vol 34 (3) ◽  
pp. 1515-1541 ◽  
Author(s):  
Guo-Liang Ma ◽  
Qiang Xie ◽  
Andrew S. Whittaker
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Simulations ◽  
Seismic Vulnerability ◽  
Power Transformer ◽  
Element Model ◽  
Ground Shaking ◽  
Earthquake Simulator ◽  
Physical Experiments ◽  
Seismic Tests

Power transformers and bushings are key pieces of substation equipment and are vulnerable to the effects of earthquake shaking. The seismic performance of a 1,100 kV bushing, used in an ultra-high voltage (UHV) power transformer, is studied using a combination of physical and numerical experiments. The physical experiments utilized an earthquake simulator and included system identification and seismic tests. Modal frequencies and shapes are derived from white noise tests. Acceleration, strain, and displacement responses are obtained from the uniaxial horizontal seismic tests. A finite element model of the 1,100 kV bushing is developed and analyzed, and predicted and measured results are compared. There is reasonably good agreement between predicted and measured responses, enabling the finite element model to be used with confidence for seismic vulnerability studies of transformer-bushing systems. A coupling of the experimental and numerical simulations enabled the vertically installed UHV bushing to be seismically qualified for three-component ground shaking with a horizontal zero-period acceleration of 0.53 g.

Spectral ratio comparison between translation and rotational records from induced seismic events.

2021 ◽  
Author(s):  
Dariusz Nawrocki ◽  
Maciej Mendecki ◽  
Lesław Teper
Keyword(s):  
Seismic Data ◽  
Seismic Station ◽  
Spectral Ratio ◽  
Numerical Differentiation ◽  
Vertical Axis ◽  
Frequency Range ◽  
Signal Ratio ◽  
Seismic Waveforms ◽  
Seismic Tests ◽  
Rotation Spectrum

<p>The seismic observations of the rotational signals are a field of seismology that is constantly developed. The recent research concerns sensors technology and its potential application in seismic tests. This study presents the results of a comparative analysis of rotational and translational seismic records using the horizontal-to-vertical spectral ratio (HVSR) method. In terms of transitional signal ratio, we have used the name of HVSR, but in terms of rotational component spectra, we have introduced a torsion-to-rocking spectral ratio (TRSR) which corresponds to horizontal rotation spectrum to vertical rotation spectrum. It has to be noticed that rotation in the horizontal axes has a vertical character and rotation in the vertical axis has a horizontal character.</p><p>The comparison was carried out between velocity signals of translational and rotational records, as well as, between acceleration signals respectively. All seismic data were recorded by two independent sensors: the rotational seismometer and translational accelerometer at the Imielin station, located in the Upper Silesia Coal Basin (USCB), Poland. The seismic data composed of three-component seismic waveforms related to 56 recorded tremors which were located up to 1,5 km from the seismic station and they resulted from the coal extractions carried out in the neighboring coal mines. The rotational acceleration was obtained by numerical differentiation and the translational velocity was produced by numerical integration.</p><p>The conducted spectral analyses allowed to estimate the range of frequency in which the rotational HVSR and the corresponded translational HVSR are comparable. The analysis of HVSR/TRSR curves (in the selected frequency range of 1Hz to 10Hz) showed a strong correlation between the spectral ratios for the velocity signals (translational and rotational) in the frequency range of 1Hz to 2Hz. Respectively, the comparison of the accelerometer signals indicated the correlation between HVSR/TRSR curves in the frequency range of 1Hz to 3Hz. Moreover, both of the TRSR (for velocity and acceleration) showed additional maxima in the same frequency range of 3Hz to 5Hz. These relatively high-frequency maxima did not correspond to translational spectra.  </p>

Practical Controller Design of Hybrid Experimental System for Seismic Tests

2009 ◽  
Vol 56 (3) ◽  
pp. 628-634 ◽  
Author(s):  
K. Seki ◽  
M. Iwasaki ◽  
M. Kawafuku ◽  
H. Hirai ◽  
K. Kishida
Keyword(s):  
Controller Design ◽  
Experimental System ◽  
Seismic Tests

scholarly journals Characterization of Shear Strength of FRP Anchors

2018 ◽  
Vol 199 ◽  
pp. 09008
Author(s):  
Philipp Mahrenholtz ◽  
Jae-Yeol Cho ◽  
Ja-Min Park ◽  
Rolf Eligehausen
Keyword(s):  
Load Capacity ◽  
Concrete Surface ◽  
Shear Loading ◽  
Seismic Retrofitting ◽  
Static Tests ◽  
Cyclic Shear ◽  
Concrete Body ◽  
Seismic Tests ◽  
Frp Sheet

A critical performance aspect of FRP retrofitted concrete elements is the bonding of the FRP sheet to the concrete surface. In general, the performance is limited by the debonding of the loaded FRP sheets from the concrete surface. One method to delay debonding and enhance the capacity is the use of FRP anchors which interlock the FRP sheet to the concrete body. FRP anchors are made of rolled FRP fibres epoxied into in predrilled boreholes. There are a considerable number of studies on FRP strengthening methods available, and also FRP anchors attract more attention of the research community recently. However, to date FRP anchors were tested in a system together with the FRP sheet attached to the concrete, inhibiting the development of general design models. Moreover, the anchor behaviour was never tested for cyclic loads, though most applications are for seismic retrofitting schemes and cyclic shear loading generally results in reduced load capacity due to fatigue failure. To overcome the deficit in knowledge, shear tests on various FRP anchors were carried out. For these tests, FRP anchors were installed in concrete specimens on a separating steel section. The FRP anchor was then directly loaded to determine the capacity of the isolated component. This paper describes the testing approach and procedure. Details on the experimental results for static tests are presented and an outlook on seismic tests is given.

Evaluation of Local Thinning Shape by LDI for Seismic Safety Evaluation of Piping System

2011 ◽  
Author(s):  
Ryo Morita ◽  
Fumio Inada ◽  
Michiya Sakai ◽  
Shin-ichi Matsuura ◽  
Shigenobu Onishi ◽  
...  
Keyword(s):  
Liquid Droplet ◽  
Safety Evaluation ◽  
Piping System ◽  
Flow Conditions ◽  
Droplet Impingement ◽  
Seismic Safety ◽  
Seismic Safety Evaluation ◽  
Droplet Behavior ◽  
Seismic Tests ◽  
The Relationship

For seismic safety evaluation of piping system with local thinning surface by liquid droplet impingement erosion (LDI), hybrid seismic tests were conducted to the piping with a locally-thinned elbow. In this paper, a method for predicting the thinning shape by LDI on the elbow is developed. To determine the thinning shape by LDI, droplet behavior at the elbow is calculated for various flow conditions and geometries. With the calculation of the collision point and velocity for each droplet, collision frequency and average collision velocity on the elbow are estimated. Then, the thinning shape on the elbow is determined with the relationship between the flow conditions and thinning rate. Finally, the evaluated thinning shape is compared with an actual LDI case for the validation of the method.

Erratum: Simple Seismic Tests of the Solar Core

2000 ◽  
Vol 544 (2) ◽  
pp. 1181-1182
Author(s):  
Dallas C. Kennedy
Keyword(s):  
Seismic Tests
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