• Title/Summary/Keyword: shaking table study

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진동대를 이용한 Geomembrane-Geotextile 사이의 동적 접촉마찰특성 평가

  • 김동진;서민우;박준범
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.09a
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    • pp.179-182
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    • 2002
  • Geosynthetics are widely used in landfill for filtration, drainage, separation and so on. For many landfill failure cases, interfaces of geosynthetics can be potential failure surfaces. Therefore, it is very Important to estimate the interface properties of geosynthetics. In this study, shaking table tests were peformed between smooth geomembrane and geotextile. From the test results, it was found that there is a limited acceleration that can be transmitted from smooth geomembrane to geotextile. And the influence of normal stress and frequencies of excitation were discussed.

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Development of the similitude law considering the intensity-dependent variation of natural frequency of pile foundation system (말뚝 기초 고유진동수의 가속도 크기 의존성을 고려한 상사법칙 개발)

  • Choi, Jung-In;Yoo, Min-Teak;Kim, Sung-Yul;Kim, Myoung-Mo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.905-912
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    • 2009
  • 1-g shaking table test is conducted to evaluate the dynamic behavior of a soil-structure system under seismic loading condition. A consistent similitude law between the model and prototype is needed to predict the behavior of the prototype structure, quantitatively. The natural frequency of geomaterial decreases with the increase of shaking intensity because of the non-linear property of the geomaterial. This phenomenon affects the applicability of similitude laws in 1-g shaking table tests. In this study, a simple method is suggested to determine the frequency of the input motions in 1-g tests in order to enhance the applicability of similitude laws. Modified input frequency is calculated using the frequency ratio with consideration of the variation of the natural frequency according to the intensity of input ground acceleration. To verify the applicability of the suggested method, a series of 1-g shaking table tests were performed for three different sizes of model piles having an overburden mass on their heads by varying the acceleration and the frequency of input motion. The acceleration amplification ratio on the overburden mass, the lateral displacement at the pile head and the maximum bending moment along the pile depth were measured. The projected behaviors of the virtual prototype based on the measured values of the model tests, where the input frequencies were calculated by the new method, showed good consistency, verifying the applicability of the suggested method.

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Seismic analysis of a masonry cross vault through shaking table tests: the case study of the Dey Mosque in Algiers

  • Rossi, Michela;Calderini, Chiara;Roselli, Ivan;Mongelli, Marialuisa;De Canio, Gerardo;Lagomarsino, Sergio
    • Earthquakes and Structures
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    • v.18 no.1
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    • pp.57-72
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    • 2020
  • This paper presents the results of a monodirectional shaking table test on a full-scale unreinforced masonry cross vault characterized by asymmetric boundary conditions. The specimen represents a vault of the mosque of Dey in Algiers (Algeria), reproducing in detail the mechanical characteristics of masonry, and the constructive details including the presence of some peculiar wooden logs placed within the vault's abutments. The vault was tested with and without the presence of two steel bars which connect two opposite sides of the vault. The dynamic behaviour of both the vault's configurations were studied by using an incremental dynamic analysis up to the collapse of the vault without the steel bars. The use of an innovative high-resolution 3D optical system allowed measure displacement data of the cross vault during the shake table tests. The experimental results were analysed in terms of evolution of damage mechanisms, and in-plane and out-of-plane deformations. Moreover, the dynamic properties of the structure were investigated by means of an experimental modal analysis.

A Study on Seismic Retrofit Design of the Stabilized Piles by 1g Shaking Table Tests and Pseudo-static Analysis (1g 진동대 실험 및 등가정적해석을 이용한 억지말뚝의 사면안정 내진보강 효과 연구)

  • Han, Jin-Tae;Cho, Jong-Suck;Yoo, Min-Taek;Lee, Seung-Hyun
    • Journal of the Korean Society of Hazard Mitigation
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    • v.11 no.2
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    • pp.93-101
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    • 2011
  • Korea has about 70% of its land classified as the mountain area, which has led to cut-slope being the result of substantial road and railway construction. However, there is currently a lack of research about the seismic retrofit design of a slope, even though many earthquakes have recently occurred at home and abroad. In this study, in order to investigate the stabilizing effect of piles against sliding during an earthquake, a series of 1 g shaking table tests and pseudo-static analyses were carried out. As a result, the stabilizing effect of piles against sliding during an earthquake was verified by the 1 g shaking table tests and the most effective result from the pseudo-static analyses was that the installation of the piles on the central part of the slope, where the failure surface included piles unlike the lower part and upper part of the slope. Furthermore, when the pile was installed on the central part of the slope, the change of the safety factor depending on the distance between the center of two piles was evaluated.

A Study on the Analysis of the Fracture Behavior of Pallet Racks due to Earthquake Load (지진하중으로 인한 팔레트 랙의 파괴 거동 분석에 관한 연구)

  • Kim, Chunggil;Heo, Gwanghee;Jeong, Seonghoon;Kim, Sun Tae;Seo, Youngdeuk;Ko, Byeongchan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.2
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    • pp.157-164
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    • 2023
  • This study aims to analyze the damage and destruction behavior of pallet racks due to external forces through shaking table test. Pallet racks is a general storage racks type consisting of column, beam, and brace to resist an external force. To analyze the safety of the pallet racks due to external force, a shaking table test was conducted to investigate the pallet racks behavior due to external force while increasing the seismic load targeting the pallet racks used in the existing logistics storage facility. As a result of the shaking table test, it was confirmed that the torsion of the pallet racks damaged the connection parts of some members located on the 1st and 2nd levels, thereby destroying the loading equipment.

Study on flexible segment efficiency for seismic performance improvement of subsea tunnel (해저터널 내진성능 향상을 위한 Flexible segment 효용성 연구)

  • Jang, Dong-In;Kim, Jong-Ill;Kwak, Chang-Won;Park, Inn-Joon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.3
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    • pp.503-515
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    • 2017
  • Underground structures that have recently become larger are required to be stable not only during normal times but also during earthquakes. Especially, it is very important to maintain the stability of the subsea tunnels during the earthquake. The objective of this paper is to verify the effectiveness of the flexible segment, which is one of the breakthrough facilities to maintain the stability of the subsea tunnel during the earthquake using the shaking table test. Another goal of this paper is to propose the optimum position of the flexible segment through 3D dynamic numerical analysis based on the verified results from shaking table tests. The 1g shaking table test considering the similarity ratio (1:100) to the cross section of the selected artificial subsea tunnel was carried out considering the Geongju and Artificial seismic waves, longitudinal and lateral wave, and with/without flexible segments eight times or more. As a result of the shaking table test, it was confirmed that the flexible segment is effective in improving the seismic performance of the undersea tunnel in all the experimental results. In addition, 3D dynamic numerical analysis was performed to select the optimum position of the flexible segment which is effective for improving seismic performance. As a result, it was confirmed that the seismic acceleration is attenuated when the flexible segment is installed adjacent to the branch section in subsea tunnel.

Design Parameter of a New Type Bi-directional Damper Using a Tuned Liquid Column Damper and a Tuned Sloshing Damper (TLCD와 TSD를 이용한 새로운 형태의 양방향 감쇠기 설계변수)

  • Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.8
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    • pp.850-856
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    • 2009
  • A new type bi-directional damper using a tuned liquid column damper(TLCD) and a tuned sloshing damper(TSD) is introduced in this study. Two dampers are usually needed to reduce wind-induced responses of tall buildings since they are along and across wind ones. The proposed damper has the advantage of controlling both responses with one damper. One of objectives of this study is to derive analytical dynamics to investigate coupled effects due to TLCD and TSD. Another objective is to address the effect of coupled control force due to TLCD and TSD on the dynamic characteristic of the damper based on analytical dynamics. Shaking table test is undertaken to experimentally grasp dynamic characteristics of the damper under white noise excitation. Its dynamic characteristic is expressed by the transfer function from the shaking table acceleration to the control force generated from the damper. Finally, its design parameters are identified based on the coupled dynamics, which include the mass ratio of horizontal liquid column to total liquid for a TLCD, the participation factor of the fundamental liquid sloshing for a TSD and damping ratio for both cases.

Experiment of a Liquid Damper Controlling Bi-directional Wind Responses of a Tall Building (초고층 건물의 양방향 풍응답 제어를 위한 액체댐퍼 실험)

  • Lee, Hye-Ri;Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.3
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    • pp.287-295
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    • 2010
  • This study deals with the design of a bi-directional damper using a tuned liquid damper(TLD) and a tuned liquid column damper(TLCD) for a SDOF building. Two dampers are usually needed to reduce wind-induced responses of tall buildings since they are along and across wind ones. The proposed damper has the advantage of controlling both responses with a single damper. The damper used in this study behaves as both a TLCD in a specific translational direction and a TLD in the other orthogonal direction. This paper presents experimental verification to confirm its control performance. First, shaking table test is carried out to investigate reducing responses by the damper. Control performance of the damper is expressed by the transfer function from shaking table accelerations to SDOF building ones. Testing results show that the damper reduced bi-directional responses of a SDOF building. Also, it reduced torsion responses.

Experimental study on high gravity dam strengthened with reinforcement for seismic resistance on shaking table

  • Wang, Mingming;Chen, Jianyun;Fan, Shuli;Lv, Shaolan
    • Structural Engineering and Mechanics
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    • v.51 no.4
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    • pp.663-683
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    • 2014
  • In order to study the dynamic failure mechanism and aseismic measure for high concrete gravity dam under earthquake, the comparative models experiment on the shaking table was conducted to investigate the dynamic damage response of concrete gravity dam with and without the presence of reinforcement and evaluate the effectiveness of the strengthening measure. A new model concrete was proposed and applied for maintaining similitude with the prototype. A kind of extra fine wires as a substitute for rebar was embedded in four-points bending specimens of the model concrete to make of reinforced model concrete. The simulation of reinforcement concrete of the weak zones of high dam by the reinforced model concrete meets the similitude requirements. A tank filled with water is mounted at the upstream of the dam models to simulate the reservoir. The Peak Ground Acceleration (PGA) that induces the first tensile crack at the head of dam is applied as the basic index for estimating the overload capacity of high concrete dams. For the two model dams with and without strengthening tested, vulnerable parts of them are the necks near the crests. The results also indicate that the reinforcement is beneficial for improving the seismic-resistant capacity of the gravity dam.

Investigation of Dynamic Characteristcs Uninterruptible Power Supply System (UPS) Using Shaking Table Tests (무정전전원장치(UPS)의 진동대 실험 및 동적특성 분석)

  • Lee, Seung-Jae;Kim, Joo-Young;Choi, Kyoung-Kyu
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.11
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    • pp.129-136
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    • 2019
  • Non-structural elements are vulnerable to earthquake ground motion. In this study, an experimental study for the electrical non-structural element was performed using tri-axial shaking table tests. A 100kVA UPS(Uninterruptible Power Supply system) was used as the test specimen. The test specimen was anchored to the concrete slab using the conventional installation detail. The input acceleration were generated in accordance with ICC-ES AC156 code. Scale factors of the input acceleration with respect to the required response spectrum defined in ICC-ES AC156 were from 25% to 600%. Based on the test results, damage and dynamic characteristics of UPS were evaluated and analyzed including natural frequency, damping ratio, acceleration time history response, dynamic amplification factor and relative displacement.