scholarly journals Quasi-Resonance Effects Observed in The 1994 Northridge Earthquake, and Others

1998 ◽  
Vol 5 (3) ◽  
pp. 153-158 ◽  
Author(s):  
Edward G. Fischer ◽  
Thomas P. Fischer
Keyword(s):  
Time History ◽  
Shaking Table ◽  
Northridge Earthquake ◽  
Shaking Table Tests ◽  
Circuit Breakers ◽  
Resonance Effects ◽  
Earthquake Records ◽  
San Fernando ◽  
Conservative Simulation ◽  
1994 Northridge Earthquake

Sine-beat phenomena have been found in the 1994 Northridge earthquake records, and they are capable of producing time-history responses and damaging quasi-resonance effects in structures. Linear, single DOF (degree of freedom) oscillators, in lieu of nonlinear, multiple DOF systems, have been found adequate to discuss the failures of tall circuit breakers during the 1971 San Fernando and the 1989 Loma Prieta quakes in California. The use of sine-beat excitation for seismic-shaking-table tests of equipment continues to be a conservative simulation of earthquakes.

Nonlinear Numerical Simulation of Shaking Table Tests of a RC Frame-Shear Wall Model

2010 ◽  
Vol 163-167 ◽  
pp. 4336-4341
Author(s):  
Tao Wang ◽  
Jing Jiang Sun ◽  
Li Yan Meng
Keyword(s):  
Numerical Simulation ◽  
Time History ◽  
Shear Wall ◽  
Paper Analysis ◽  
Shaking Table ◽  
Beam Model ◽  
Shaking Table Tests ◽  
Analysis Model ◽  
Fiber Model ◽  
Nonlinear Numerical Simulation

In this paper, to verify the effectiveness and reliability of nonlinear numerical simulation based fiber model, two computer programs (CANNY 99 and IDARC-2D), in which shear wall elements were respectively simplified by fiber model and equivalent beam model, were adopted to perform the numerical simulations of 10 times shaking table tests of a nine story 1:6 scale frame-shear wall building model in this paper. Analysis model including beam, column and wall element in CANNY 99 is elaborated in detail. Test results are compared with simulation results in some aspects such as natural frequency, time history responses, and peak value responses. Results demonstrate that fiber model and Equivalent beam model can simulate the elastic-plastic earthquake response of R.C. wall structures very well.

scholarly journals Seismic Earth Pressures of Retaining Wall from Large Shaking Table Tests

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Changwei Yang ◽  
Jian Jing Zhang ◽  
Qu Honglue ◽  
Bi Junwei ◽  
Liu Feicheng
Keyword(s):  
Wenchuan Earthquake ◽  
Retaining Wall ◽  
Time History ◽  
Earth Pressure ◽  
Shaking Table ◽  
Rock Foundation ◽  
Shaking Table Tests ◽  
The Wenchuan Earthquake ◽  
Earth Pressures ◽  
Soil Foundation

To ascertain seismic response of retaining wall in the Wenchuan earthquake, large shaking table tests are performed and an acceleration record is acted in 3 directions. In the tests, acceleration time history recorded at Wolong station in the Wenchuan earthquake is used to excite the model wall. Results from the tests show that the location of dynamic resultant earth pressure is 0.35–0.49 H from toe of the wall for road shoulder retaining wall on rock foundation, 0.33–0.42 H for embankment retaining wall on rock foundation, and 0.46–0.77 H for road shoulder retaining wall on soil foundation. Besides, dynamic earth pressure increases with the increase of ground shaking from 0.1 g to 0.9 g and the relationship is nonlinear. The distribution is closed to for PGA less than 0.4 g but larger for PGA larger than and equal to 0.4 g, especially on the soil foundation. After the comparison of measured earth pressures and theoretical results by pseudodynamic method and pseudostatic method, results of the former are consistent with those of the shaking table test, but results of the latter method are smaller than measured.

Seismic Response of an Instrumented 13-Story Steel Frame Building Damaged in the 1994 Northridge Earthquake

1997 ◽  
Vol 13 (1) ◽  
pp. 131-149 ◽  
Author(s):  
Chia-Ming Uang ◽  
Qi-Song Yu ◽  
Ali Sadre ◽  
David Bonowitz ◽  
Nabih Youssef ◽  
...  
Keyword(s):  
Time History ◽  
Regular Structure ◽  
Primary Objective ◽  
Elastic Model ◽  
Northridge Earthquake ◽  
Steel Moment Frame ◽  
Modeling And Analysis ◽  
Panel Zone ◽  
Inelastic Analysis ◽  
1994 Northridge Earthquake

This paper summarizes a case study of a 13-story welded steel moment frame (WSMF) building affected by the 1994 Northridge earthquake. The building, which was instrumented, sustained extensive damage to its welded connections. Ground motion records from the basement and response records from the sixth and twelfth floors were available. Damage data was collected with post-earthquake inspection and testing of each joint. The primary objective of the study was to compare modeled behavior with recorded response in order to assess the value of present analytical tools and modeling techniques for predicting the distribution and severity of connection failures. Calculated elastic time-history displacements matched well with recorded displacements in the E-W direction, less so in the heavily-damaged N-S direction where the elastic model was unable to simulate fractured moment connections. In the elastic analyses, joint demand was represented by beam demand-capacity ratios (DCRs). The highest beam DCRs were concentrated between the second and seventh floors; these locations correlated strongly with observed damage. Inelastic time-history analyses improved the displacement match in the N-S direction. They also indicated that panel zone yielding would have controlled the intended ductile response. This study suggests that for a regular structure, current modeling and analysis tools for both elastic and inelastic analysis, while unable to simulate premature brittle fractures, can be useful for predicting in a probabilistic way the intensity and distribution of damage expected in moderate seismic events.

scholarly journals Seismic Response of Flat Ground and Slope Models through 1 g Shaking Table Tests and Numerical Analysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1875
Author(s):  
Yong Jin ◽  
Hoyeon Kim ◽  
Daehyeon Kim ◽  
Yonghee Lee ◽  
Haksung Kim
Keyword(s):  
Numerical Analysis ◽  
Seismic Waves ◽  
Shaking Table Test ◽  
Time History ◽  
Shaking Table ◽  
Numerical Analyses ◽  
Shaking Table Tests ◽  
Shear Box ◽  
Laminar Shear ◽  
Flat Ground

In order to verify the reliability of numerical analysis, a series of 1 g shaking table tests for flat ground and slope were conducted using a laminar shear box subjected to different seismic waves. Firstly, numerical analyses, using the DEEPSOIL and ABAQUS software, were done to compare the results of flat ground experiments. After that, finite element analyses with ABAQUS were conducted to compare the results of slope experiments. For numerical analyses, considering the influence of the boundary, the concept of adjusted elastic modulus was proposed to improve the simulation results. Based on the analyses, it is found that in terms of acceleration-time history and spectral acceleration, the numerical analysis results are in good agreement with the experiment results. This implies that numerical analysis can capture the dynamic behavior of soil under 1 g shaking table test conditions.

scholarly journals Shaking table tests of a base isolated structure with Double Concave Friction Pendulum bearings

2015 ◽  
Vol 48 (2) ◽  
pp. 136-144 ◽  
Author(s):  
Felice C. Ponzo ◽  
Antonio D. Cesare ◽  
Gianmarco Leccese ◽  
Domenico Nigro
Keyword(s):  
Base Isolation ◽  
Experimental Testing ◽  
Design Procedure ◽  
Time History ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Isolation System ◽  
Sliding Surfaces ◽  
Residual Displacements ◽  
Friction Pendulum

An extensive experimental testing programme named JETBIS project (Joint Experimental Testing of Base Isolation Systems) was developed within the RELUIS II project (Task 2.3.2) and RELUIS III project (Line 6) involving partners from different Italian universities. This paper describes the seismic tests performed by the research unit of University of Basilicata (UNIBAS) on an isolation system based on Double Concave Friction Pendulum (DCFP) bearings. The DCFP bearing contains two separate concave sliding surfaces and exhibits different hysteretic properties at different stages of displacement response. The main objective of this work is to evaluate the horizontal response of the DCFP isolators by means of controlled-displacement tests and shaking table tests. The experimental model was a 1/3 scaled steel framed structure with one storey and one bay in both directions. Four DCFP bearings with equal properties of the sliding surfaces were considered. In this work, three different sliding surface conditions (with and without lubrication) have been studied. The isolated base model was subjected to 8 natural earthquakes of increasing seismic intensities and considering two mass configurations (with both symmetrical and eccentric masses). The reliability of the design procedure considered for the isolation system was verified also when relevant residual displacements occurred due to previous earthquakes. In this paper, the comparisons between the experimental outcomes and the numerical results of nonlinear time-history analyses using SAP2000 are shown.

Nonlinear Analyses of an Instrumented Structure Damaged in the 1994 Northridge Earthquake

1998 ◽  
Vol 14 (2) ◽  
pp. 265-283 ◽  
Author(s):  
Y. Roger Li ◽  
James O. Jirsa
Keyword(s):  
Nonlinear Dynamic ◽  
Shear Failure ◽  
Time History ◽  
Lateral Force ◽  
Economic Losses ◽  
Northridge Earthquake ◽  
Dynamic Time ◽  
Nonlinear Dynamic Analyses ◽  
Structural Engineers ◽  
1994 Northridge Earthquake

The extensive damage and economic losses that occurred during the 1994 Northridge and other recent moderate earthquakes have stimulated structural engineers to consider how to protect economic investment besides meeting life safety requirements of buildings. The equivalent lateral force procedure for seismic design is based on implicit consideration of inelastic response of structures in earthquakes. Experience with past earthquakes has indicated that this procedure is inadequate in controlling damage in buildings. The objective of this study is to demonstrate the capability of nonlinear dynamic analyses to predict performance of reinforced concrete structures subjected to earthquake ground motions. An instrumented building damaged during the 1994 Northridge earthquake was analyzed using DRAIN-2D, and the results were compared with recorded response data. Both nonlinear dynamic time history and nonlinear static push-over analyses were performed, and correlations between these two nonlinear analysis methods were studied. A simplified shear failure model was proposed in the study.

scholarly journals Study on Seismic Performance of a Mold Transformer through Shaking Table Tests

2020 ◽  
Vol 10 (1) ◽  
pp. 361 ◽  
Author(s):  
Ngoc Hieu Dinh ◽  
Seung-Jae Lee ◽  
Joo-Young Kim ◽  
Kyoung-Kyu Choi
Keyword(s):  
Shaking Table Test ◽  
Damping Ratio ◽  
Time History ◽  
Relative Displacement ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Acceleration Time ◽  
Boundary Limit ◽  
Acceleration Time Histories ◽  
Operational Test

This study presents an experimental seismic investigation of a 1000 kVA cast resin-type hybrid mold transformer through tri-axial shaking table tests. The input acceleration time histories were generated in accordance with the specifications recommended by the International Code Council Evaluation Services Acceptance Criteria ICC-ES AC156 code, with scaling factors in the range of 25–300%. The damage and the dynamic characteristics of the mold transformer were evaluated in terms of the fundamental frequency, damping ratio, acceleration time history responses, dynamic amplification factors, and relative displacement. The shaking table test results showed that the damage of the mold transformer was mainly governed by the severe slippage of the spacers and the loosening of the linked bolts between the bottom beam and the bed beam. In addition, the maximum relative displacement at the top beam in Y and Z-directions exceeded the boundary limit recommended by the Korean National Radio Research Agency. Moreover, the operational test of the specimen was performed based on the IEC 60076-11 Standard before and after the shaking table test series to ensure the operational capacity of the transformer.

Shaking Table Tests of a Free-Standing Cultural Relic Strengthened by Plastic Fasteners

2012 ◽  
Vol 450-451 ◽  
pp. 1513-1517
Author(s):  
Qian Zhou ◽  
Wei Ming Yan ◽  
Jin Bao Ji
Keyword(s):  
Time History ◽  
Simulation Method ◽  
Test Method ◽  
Shaking Table ◽  
Finite Element Models ◽  
Shaking Table Tests ◽  
Seismic Responses ◽  
Acceleration Response ◽  
Free Standing ◽  
Peak Displacement

Plastic fastener is a typical strengthening material for museum movable cultural relics in China.To find out strengthening effects of this material,by shaking table tests seismic responses of a ceramic relic in a 1:1 scale showcase model were studied.2 boundary conditions of the relic were considered:free-standing and strengthened by plastic fastener. By white noise excitation basic frequency of the showcase was obtained; by inputting El-centro earthquake waves of different intensities,seismic responses of both showcase and relic were studied,aseismic results of plastic fasteners were discussed. By simulation method finite element models for the showcase and strengthened relic were built,modal as well as time history analyses were carried out to validate the effectivity of shaking table tests.Results show that prominent frequency ingredients of the showcase are far greater than those of the input earthquake waves,thus the showcase is not damaged seriously; for the relic after it is strengthened by plastic fasteners,its peak displacement and acceleration response values decrease,which still embody obviously under strong earthquakes.Thus by plastic fasteners the relic can be effectively strengthened. Besides,simulation results are well in accordance with those of shaking table tests,which proves effectivity of the test method.

Deformation of Embankments Due to Liquefaction During 1994 Northridge Earthquake

1998 ◽  
Vol 1633 (1) ◽  
pp. 9-18
Author(s):  
J.P. Bardet ◽  
C.A. Davis
Keyword(s):  
Ground Motions ◽  
Geotechnical Engineering ◽  
Three Dimensional ◽  
Northridge Earthquake ◽  
Earth Dams ◽  
Case Histories ◽  
Hydraulic Fill ◽  
Engineering Community ◽  
San Fernando ◽  
1994 Northridge Earthquake

The 1994 Northridge and 1971 San Fernando earthquakes subjected the Lower and Upper San Fernando Dams of the Van Norman Complex in the San Fernando Valley, California, to strong near-source ground motions. In 1994, these earth dams, which were out of service and retained only a few meters of water, extensively cracked and settled because of liquefaction of their hydraulic fill. The Lower San Fernando Dam moved more than 15 cm upstream as the hydraulic fill liquefied beneath its upstream slope. The Upper San Fernando Dam moved even more, and it deformed in a complex three-dimensional pattern. The responses of the Lower and Upper San Fernando Dams during the 1994 Northridge earthquake, although less significant than in 1971, provided the geotechnical engineering community with two useful case histories.

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