• 제목/요약/키워드: earthquake vibration

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Vibration Control of Structure Using the Toggle System (Toggle 시스템을 이용한 구조물의 진동제어)

  • 황재승;송진규;강경수;윤태호
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.03a
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    • pp.491-498
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    • 2003
  • The purpose of this study is to analyze the geometric nonlinearity of a toggle system and to evaluate the vibration control performance when the toggle system with a viscous damper was applied to a structure. Numerical analysis shows that the relative displacement of the structure can be amplified by amplification mechanism of the toggle system and the capacity of the damper can be reduced without the loss of vibration control performance. It is also observed that the geometric nolinearity of toggle system using the linear viscous damper has little effect on the performance.

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Forced Vibration Testing of a Four-Story Reinforced Concrete Frame Building (철근콘크리트조 4층 골조건물의 강제진동실험)

  • Yu, Eun-Jong;Wallace, John W.
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.2 s.54
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    • pp.27-38
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    • 2007
  • A series of forced vibration tests and ambient vibration measurement was conducted on a four-story reinforced concrete building damaged in the 1994 Northridge earthquake. Both low amplitude broadband and moderate amplitude harmonic excitation were applied using a linear shaker and two eccentric mass shakers, respectively, and ambient vibrations were measured before and after each forced vibration test. Accelerations, interstory displacements, and curvature distributions were monitored using accelerometers, LVDTs and concrete strain gauges. Natural frequencies and the associated mode shapes fur the first 7 modes were identified. Fundamental frequencies determined from the eccentric mass shaker tests were 70% to 75% of the values determined using ambient vibration data, and 92% to 93% of the values determined using the linear shaker test data. Larger frequency drops were observed in the NS direction of the building, apparently due to damage that was induced during the Northridge earthquake.

Application of Vibration Prediction Method Using Response Spectrum with Amplification Factor (증폭계수를 이용한 진동 예측기법의 적용)

  • 심재수;황의승;김덕중;윤종오
    • Journal of the Earthquake Engineering Society of Korea
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    • v.1 no.4
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    • pp.37-43
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    • 1997
  • Damages and public complaints are increased due to construction noise and vibration from several sources. It is urgently needed to develop the easy and practical method to estimate the vibration effect. In this study, to predict the vibration effect, the method using the response spectrum with amplification factor concepts prroposed by Newmark and Hall is used. Also the applicability of the method is examined. Vibration measurement on subway structure, foundation and building structures are performed and the results show that the provided method is practical and can be used to predict the vibration effect.

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A Development of Real-time Vibration Monitoring and Analysis System Linked to the Integrated Management System of Ministry of Public Safety and Security (국민안전처 통합관리시스템 연계 가능한 시설물 진동 감지 및 분석 시스템 개발)

  • Lim, Ji-Hoon;Jung, Jin-Woo;Moon, Dae-Joong;Choi, Dong-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.3
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    • pp.130-139
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    • 2016
  • A frequency of earthquake occurrence in the Republic of Korea is increasing over the past few decades. In this situation, an importance of earthquake prevention comes to the fore because the earthquake does damage to structures and causes severe damage of human life. For the earthquake prevention, a real-time vibration measurement for structures is important. As an example, the United States of America and Japan have already been monitoring real-time earthquake acceleration for the important structures and the measured acceleration data has been managed by forming database. This database could be used for revising the seismic design specifications or predicting the damage caused by earthquake. In Korea, Earthquake Recovery Plans Act and Enforcement Regulations are revised and declared lately. Ministry of Public Safety and Security is constructing a integrated management system for the measured earthquake acceleration data. The purpose of this research is to develop a real-time vibration monitoring and analysis system for structures which links to the integrated management system. The developed system contains not only a monitoring function to show real-time acceleration data but also an analysis system to perform fast fourier transform, to obtain natural frequency and earthquake magnitude, to show response spectrum and power spectrum, and to evaluate structural health. Additionally, this system is designed to be able to link to the integrated management system of Ministry of Public Safety and Security. It is concluded that the developed system can be useful to build a safety management network, minimize maintenance cost of structures, and prevention of the structural damage due to earthquake.

Ambient vibration tests of XV century Renaissance Palace after 2012 Emilia earthquake in Northern Italy

  • Cimellaro, Gian Paolo;De Stefano, Alessandro
    • Structural Monitoring and Maintenance
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    • v.1 no.2
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    • pp.231-247
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    • 2014
  • This paper focuses on the dynamic behaviour of Mirandola City Hall (a XV century Renaissance Palace) that was severely damaged during May 2012 Emilia earthquake in Northern Italy. Experimental investigations have been carried out on this monumental building. Firstly, detailed investigations have been carried out to identify the identification of the geometry of the main constructional parts as well as the mechanical features of the constituting materials of the palace. Then, Ambient Vibration Tests (AVT) have been applied, for the detection of the main dynamic features. Three output-only identification methods have been compared: (i) the Frequency Domain Decomposition, (ii) the Random Decrement (RD) and the (iii) Eigensystem Realization Algorithm (ERA). The modal parameters of the Palace were difficult to be identified due to the severe structural damage; however the two bending modes in the perpendicular directions were identified. The comparison of the three experimental techniques showed a good agreement confirming the reliability of the three identification methods.

Vibration Reaponse Analysis of frames with energy absober installed in Beams (보 제진 프레임의 진동응답해석)

  • Lee, Ho
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1997.10a
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    • pp.159-166
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    • 1997
  • The purpose of this thesis is to derive a theoretical model of the hysteretic resistance of the visco-elastic damper based on test results of harmonic excitation and to investigate of the basis of theory and experiment the effect of vibration control and response characteristics of portal frames degree vibration systems provided with the damper. The behaviour of a visco-elastic degree under dynamic loading is idealized by a model of the theory of visco-elasticity, i.e. a four-parameter model formed as a parallel combination of Maxwell fluid and Kelvin-Voigh models and its constitutive equation is derived. The model parameters are determined for a tested damper from the datas of harmonic excitation tests. The theoretical model of the damper is incorporated in equation fo motion of single degree of freedom. A computer program for solving the equation is written using Runge-kuttas's numerical integration scheme. Using this analysis program test cases of the earthquake excitation are simulated and the results of the simulation are the results of the simulation are the results of the simulation are compared with the test results.

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Evaluation of Serviceability due to Vibration of Slab (건축구조물의 슬래브 진동에 의한 사용성 평가 연구)

  • 우운택
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.10a
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    • pp.245-250
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    • 2000
  • Recent building structures are superior in its ability but they are light and fiexible, and so have problems of vibration. In general, the serviceability of RC slabs was known to be good against vibration because of its hardness. However recent high-rise apartment slabs are mostly light and long, the serviceability about vibration problems of RC slabs was performed. Basic information and its influence on vibrations of RC slabs were revealed. Also, its serviceability against vibration was examined. Many tests were conducted on existing building located in Chung-Nam area. As a results, damping ratio, natural frequency, acceleration amplitude and displacement amplitude which were used to examine serviceability of the RC slabs were obtained. These results on the test building proved that its serviceability conditions were satified to meet the code against vibration.

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Development an Empirical Formula for the Friction Coefficient of a Circular Friction Damper (원형 마찰 감쇠기 특성의 실험식 개발)

  • Shin, Yong-Woo;Lee, Sang-Kwon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.6
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    • pp.491-498
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    • 2011
  • The structural vibration due to earthquake or outside impact causes serious problem for building safety. A dynamic model of a friction damper which can be constructed and installed easily is needed to reduce the vibration of the building. In this paper, the experimental equation of a circular friction damper is derived and designed for reduction of a earthquake vibration of a building. The developed experimental equation is defined to simply design the capacity on design of the circular friction damper based on the results of the performance test. Finally this experimental equation can be used for the design of a circular friction damper.

Determination of seismic hazard and soil response of a critical region in Turkey considering far-field and near-field earthquake effect

  • Sonmezer, Yetis Bulent;Celiker, Murat
    • Geomechanics and Engineering
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    • v.20 no.2
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    • pp.131-146
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    • 2020
  • Evaluation of earthquake impacts in settlements with a high risk of earthquake occurrence is important for the determination of site-specific dynamic soil parameters and earthquake-resistant structural planning. In this study, dynamic soil properties of Karliova (Bingol) city center, located near to the intersection point of the North Anatolian Fault Zone and the East Anatolian Fault Zone and therefore having a high earthquake risk, were investigated by one-dimensional equivalent linear site response analysis. From ground response analyses, peak ground acceleration, predominant site period, 0.2-sec and 1-sec spectral accelerations and soil amplification maps of the study area were obtained for both near-field and far-field earthquake effects. The average acceleration spectrum obtained from analysis, for a near-field earthquake scenario, was found to exceed the design spectra of the Turkish Earthquake Code and Eurocode 8. Yet, the average acceleration spectrum was found to remain below the respective design spectra of the two codes for the far-field earthquake scenario. According to both near- and far-field earthquake scenarios in the study area, the low-rise buildings with low modal vibration durations are expected to be exposed to high spectral acceleration values and high-rise buildings with high modal vibration durations will be exposed to lower spectral accelerations. While high amplification ratios are observed in the north of the study area for the near-distance earthquake scenario, high amplification ratios are observed in the south of the study area for the long-distance earthquake scenario.

Damage Potential Analysis and Earthquake Engineering-related Implications of Sep.12, 2016 M5.8 Gyeongju Earthquake (2016년 9월 12일 M5.8 경주지진의 데미지 포텐셜 분석 및 내진공학 측면의 시사점)

  • Lee, Cheol Ho;Park, Ji-Hun;Kim, Taejin;Kim, Sung-Yong;Kim, Dong-Kwan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.7_spc
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    • pp.527-536
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    • 2016
  • This paper investigates seismic damage potential of recent September 12 M5.8 Gyeongju earthquake from diverse earthquake engineering perspectives using the accelerograms recorded at three stations near the epicenter. In time domain, strong motion durations are evaluated based on the accelerograms and compared with statistical averages of the ground motions with similar magnitude, epicentral distance and soil conditions, while Fourier analysis using FFT is performed to identify damaging frequency contents contained in the earthquake. Effective peak ground accelerations are evaluated from the calculated response spectra and compared with apparent peak ground accelerations and the design spectrum in KBC 2016. All these results are used to consistently explain the reason why most of seismic damage in the earthquake was concentrated on low-rise stiff buildings but not quite significant. In order to comparatively appraise the damage potential, the constant ductility spectrum constructed from the Gyeongju earthquake is compared with that of the well-known 1940 El Centro earthquake. Deconvolution analysis by using one accelerogram speculated to be recorded at a stiff soil site is also performed to estimate the soil profile conforming to the response spectrum characteristics. Finally, response history analysis for 39- and 61-story tall buildings is performed as a case study to explain significant building vibration felt on the upper floors of some tall buildings in Busan area during the Gyeongju earthquake. Seismic design and retrofit implications of M5.8 Gyeongju earthquake are summarized for further research efforts and improvements of relevant practice.