• 한국재난정보학회 논문집
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• 제17권3호
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• pp.500-511
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• 2021

연구목적: 후쿠시마 원자력 발전소 폭발사고 발생 당시의 재난상황, 주민보호를 위한 비상발령 상황, 주민 피난 상황에 대한 조사와 더불어 당시 주민보호 시스템에 있어서 제기된 문제점 및 조치사항에 대한 조사를 수행함으로서, 국내 원자력 재해를 대비한 주민 피난 대책 수립 과정에서 검토해야만 하는 시사점을 도출하고자 한다. 연구방법: 동일본 대지진 직후부터 현재까지 일본의 국가, 국회, 지자체 및 관련기관으로부터 발행된 보고서를 중심으로 문헌조사를 수행하였다. 연구결과: 후쿠시마 원자력발전소 폭발사고 발생 당시의 주민의 피난과정에서 도출된 문제점과 대응방안에 대한 조사 결과를 통하여 국내의 방사능 재해 대책 수립과정에 있어서 검토해야만 하는 사항을 도출하였다. 결론: 검토 사항을 크게 4가지로 분류하였으며 각 분류에 따른 상세 검토사항을 제시하였다.

• Smart Structures and Systems
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• 제5권3호
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• pp.209-221
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• 2009

A control algorithm for seismic protection of building structures based on the theory of variable structural control or sliding mode control is presented. The paper focus in the design of sliding surface. A method for determining the sliding surface by pole assignment algorithm where the poles of the system in the sliding surface are obtained on-line, based on the frequency content of the incoming earthquake signal applied to the structure, is proposed. The proposed algorithm consists of the following steps: (i) On-line FFT process is applied to the incoming part of the signal and its frequency content is recognized. (ii) A transformation of the frequency content to the complex plane is performed and the desired location of poles of the controlled structure on the sliding surface is estimated. (iii) Based on the estimated poles the sliding surface is obtained. (iv) Then, the control force which will drive the response trajectory into the estimated sliding surface and force it to stay there all the subsequent time is obtained using Lyapunov stability theory. The above steps are repeated continuously for the entire duration of the incoming earthquake. The potential applications and the effectiveness of the improved control algorithm are demonstrated by numerical examples. The simulation results indicate that the response of a structure is reduced significantly compared to the response of the uncontrolled structure, while the required control demand is achievable.

• 한국지진공학회논문집
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• 제14권6호
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• pp.45-53
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• 2010

지진 시 낙교는 교량의 기능을 상실하는 가장 심각한 피해의 하나로서 반드시 피해야 한다. 교량 받침의 파괴로 인한 낙교를 방지하기 위한 방법의 하나로서 국내에서는 받침보호장치가 많이 사용되고 있다. 교량 받침부의 옆의 빈 공간에 설치되어 상부구조로부터 전달되는 지진하중을 부담하여 받침의 파괴를 방지한다. 이러한 받침보호장치가 충분한 내진성능을 발휘하기 위해서는 받침보호장치 본체뿐만 아니라 이를 교량에 고정시키는 앵커부의 강도도 함께 확보되어야 한다. 국내에서는 이들 앵커부의 설계 방법이 확립되지 않아서 받침보호장치의 공급업체가 제공하는 설계도에 따라 시공되어 왔다. 이에 본 연구에서는 베드블록의 높이가 다른 받침보호장치를 대상으로 하여 앵커부의 성능을 실험을 통하여 확인하였고 내진성능을 확보하기 적절한 설계법을 제시하였다.

• 한국화재소방학회논문지
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• 제26권3호
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• pp.100-105
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• 2012

본 연구에서는 수계소화설비 가압송수장치의 파이프라인에 대한 내진설계를 수행하였다. 내진해석에 필요한 내진설계용 스펙트럼에 대응하는 인공지진 진동파형을 작성하였고, 작성된 인공지진 진동에 대한 응답 스펙트럼 가속도를 결정하여 등가정적하중을 결정하였다. 내진설계를 위한 공학적 기반을 구축하였으며, 수계 및 가스계 파이프 시스템의 내진설계를 위한 등가정적해석법을 제시하였다. 또한 본 연구의 결과로부터 수계설비의 파이프라인뿐만 아니라 소방설비의 내진설계 및 성능평가에 응용할 수 있는 기틀을 마련하였다. 향후 진도규모 및 지반종류에 따른 추가적인 연구가 수행된다면 소방시스템의 신뢰성 향상과 안전성 제고, 성능위주설계가 이루어질 수 있을 것으로 본다.

• 한국방재안전학회논문집
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• 제10권1호
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• pp.85-90
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• 2017

본 연구는 빌딩과 공공시설에 설치되는 중요 전기 시설물인 수배전반이, 규모 8.3급 지진에도 국내최초로 정상적으로 작동될 수 있도록, 전기를 사용하는 각종 시설물 및 기계장치의 전원공급 및 제어하는 수배전반 하부에 상하굴절형 내진패드를 설치하여, 수배전반 하부구조 보호와 상부에 케이블 단락방지 등이 가능하도록 하여, 상하좌우 모든 지진파에 잘 적응되는 내진형 수배전반 제조기술로 한국전력이 기준으로 제시한 GR-63-CORE(규모 8.3 급) 내진성능을 만족하는, 내진형 수배전반 방재기술이다. 연구 성과로서, 전기 및 통신 기반시설을 보호할 수 있게 되어 지진발생시 전기시설을 정상상태로 복구하는 시간을 단축하는데 기여할 수 있고, 지진발생시 전기공급 시설의 파괴로 인한 화재발생을 방지할 수 있어 일본의 경우처럼 대규모 지진 발생시 발생하는 화재의 확산을 최소화하여 인명피해와 재산피해를 최소화할 수 있으며, 시민들이 대규모 지진을 겪은 후에도 일상생활로 신속히 복구할 수 있는 전기기반시설을 확보 등에 기여할 수 있다. 또한, 통신 및 전산실의 장비의 내진을 확보하기 위하여, 본 기술이 적용될 수 있고, 나아가 지진시 기반이 흔들려 시설기능이 정지될 수 있는 분야에도 다양하게 적용될 수 있을 것이다.

• Structural Engineering and Mechanics
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• 제61권3호
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• pp.419-426
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• 2017

Recently, the transportation of dangerous explosive goods is increasing, which makes vehicle blasting accidents a potential threat for the safety of bridge structures. In addition, blasting accidents happen more easily when earthquake occurs. Excessive dynamic response of bridges under extreme loads may cause local member damage, serviceability issues, or even failure of the whole structure. In this paper, a new explosion-proof and aseismic system is proposed including cable support damping bearing and steel-fiber reinforced concrete based on the existing researches. Then, considering one 40m-span simply supported concrete T-bridge as the prototype, through scale model test and numerical simulation, the dynamic response of the bridge under three conditions including only earthquake, only blast load and the combination of the two extreme loads is obtained and the applicability of this explosion-proof and aseismic system is explored. Results of the study show that this explosion-proof and aseismic system has good adaptability to seism and blast load at different level. The reducing vibration isolation efficiency of cable support damping bearing is pretty high. Increasing cables does not affect the good shock-absorption performance of the original bearing. The new system is good at shock absorption and displacement limitation. It works well in reducing the vertical dynamic response of beam body, and could limit the relative displacement between main girder and capping beam in different orientation so as to solve the problem of beam falling. The study also shows that the enhancement of steel fibers in concrete could significantly improve the blast resistance of main beam. Results of this paper can be used in the process of antiknock design, and provide strong theoretical basis for comprehensive protection and support of girder bridges.

• Earthquakes and Structures
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• 제11권6호
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• pp.1123-1141
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• 2016

To explore the application of traditional tuned mass dampers (TMDs) to the earthquake induced vibration control problem, a pounding tuned mass damper (PTMD) is proposed by adding a viscoelastic limitation to the traditional TMD. In the proposed PTMD, the vibration energy can be further dissipated through the impact between the attached mass and the viscoelastic layer. More energy dissipation modes can guarantee better control effectiveness under a suite of excitations. To further reduce mass ratio and enhance the implementation of the PTMD control, multiple PTMDs (MPTMD) control is then presented. After the experimental validation of the proposed improved Hertz based pounding model, the basic equations of the MPTMD controlled system are obtained. Numerical simulation is conducted on the benchmark model of the Canton Tower. The control effectiveness of the PTMD and the MPTMD is analyzed and compared under different earthquake inputs. The sensitivity and the optimization of the design parameters are also investigated. It is demonstrated that PTMDs have better control efficiency over the traditional TMDs, especially under more severe excitation. The control performance can be further improved with MPTMD control. The robustness can be enhanced while the attached mass for each PTMD can be greatly reduced. It is also demonstrated through the simulation that a non-uniformly distributed MPTMD has better control performance than the uniformly distributed one. Parameter study is carried out for both the PTMD and the MPTMD systems. Finally, the optimization of the design parameters, including mass ratio, initial gap value, and number of PTMD in the MPTMD system, is performed for control improvement.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.308-315
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• 2005

The capacity protection is normally related with slenderness effect of the columns, force transfer in connections between columns and adjacent elements, and shear design of columns. It is intends to prevent brittle failure of the structural components of bridges, so that the whole bridge system may show ductile behavior and failure during earthquake events. For bridge systems, this means it is necessary to assess the overstrength capacity of columns prior to proceeding with the design of foundation and superstructure. The objective of this paper is to develop a capacity design approach that applies an overstrength factor for determination of possible maximum shear force in the plastic hinge zone of reinforced concrete bridge columns. In order to estimate and determine overstrength factor, material strength was developed to investigate for actual material strength total 3,407 steel and 5,405 concrete by domestic product. Based on actual material strength, this paper was conducted on moment overstrength factors using moment-curvature analysis program. And also design recommendations for capacity design are presented to revise the annual report, KEERC 2002.

• Earthquakes and Structures
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• 제16권5호
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• pp.523-532
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• 2019

Different types of gas reservoir such as Liquid Natural Gas (LNG) are among the strategic infrastructures, and have great importance for any government or their private owners. To keep the tank and its contents safe during earthquakes especially if the contents are of hazardous or flammable materials; using seismic protection systems such as base isolator can be considered as an effective solution. However, the major deficiency of this system can be the large deformation in the isolation level which may lead to the failure of bearing system. In this paper, as a solution, the efficacy of an optimally designed combined vibration control system, the combined laminated rubber isolator and rotational friction damper, is investigated to evaluate the enhancement of an existing metal tank response under both far- and near-field earthquakes. Responses like impulsive and convective accelerations, base shear, and sloshing height are studied herein. The probabilistic framework is used to consider the uncertainties in the structural modeling, as well as record-to-record variability. Due to the high calculation cost of probabilistic methods, a simplified structural model is used. By using the Mont-Carlo simulation approach, it is revealed that this combined isolation system is a highly reliable system which provides considerable enhancement in the performance of reservoir, not only leads to the reduction of probability of catastrophic failure of the tank but also decrease the reservoir damage during the earthquake. Moreover, the relative displacement of the isolation level is controlled very well by this combined system.

• Smart Structures and Systems
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• 제26권4호
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• pp.481-493
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• 2020

The negative stiffness spring and inerter are both characterized by the negative stiffness effect in the force-displacement relationship, potentially yielding an amplifying mechanism for dashpot deformation by being incorporated with a series tuning spring. However, resisting forces of the two mechanical elements are dominant in different frequency domains, thus leading to necessary complementarity in terms of vibration control and the amplifying benefit. Inspired by this, this study proposes a Negative Stiffness Inerter System (NSIS) as an earthquake protection system and developed analytical design formulae by fully utilizing its advantageous features. The NSIS is composed of a sub-configuration of a negative stiffness spring and an inerter in parallel, connected to a tuning spring in series. First, closed-form displacement responses are derived for the NSIS structure, and a stability analysis is conducted to limit the feasible domains of NSIS parameters. Then, the dual advantageous features of displacement reduction and the dashpot deformation amplification effect are revealed and clarified in a parametric analysis, stimulating the establishment of a displacement-based optimal design framework, correspondingly yielding the design formulae in analytical form. Finally, a series of examples are illustrated to validate the derived formulae. In this study, it is confirmed that the synergistic incorporation of the negative stiffness spring and the inerter has significant energy dissipation efficiency in a wide frequency band and an enhanced control effect in terms of the displacement and shear force responses. The developed displacement-based design strategy is suitable to utilize the dual benefits of the NSIS, which can be accurately implemented by the analytical design formulae to satisfy the target vibration control with increased energy dissipation efficiency.