• 한국지진공학회논문집
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• 제15권3호
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• pp.37-43
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• 2011

구조물 내 설치된 파이프시스템은 주로 내부구성원들의 인간생활에 근간이 되는 기반시설로서 현대 도시생활의 생명선과 같은 역할을 한다. 이들 구조물 내 파이프시스템이 만약 지진발생에 의하여 손상될 경우 1차적으로 구조물 내 기능성이 저하되고 구조물 내 많은 정신적, 물질적 피해가 발생할 수 있다. 실제 내진공학에서 지진발생에 따른 비구조재요소의 거동은 크게 중요하게 고려되지 않으나 인적 및 물적 피해와 매우 밀접하게 연관되는 가스 혹은 수계파이프시스템에 대한 비구조적 요소의 거동예측 및 성능평가 연구는 보다 효과적인 구조물 유지관리를 위하여 그 필요성이 크다고 판단된다. 본 연구는 현재 일반적으로 널리 시공되어져 있는 노후 철근콘크리트 빌딩구조물 내 설치된 가스 혹은 수계파이프시스템에 대하여 실제 지진발생이 예측되는 거동을 살펴보고 이들 거동에 따른 성능평가 및 현 설계기준에 대한 검토도 병행하여 수행하고자 한다. 이를 위하여 본 연구에서는 해석적으로 발생 가능한 총 10회의 지진파에 대하여 현재 실제 건물 내 기설치된 수계파이프시스템 모델링 및 해석을 통하여 그 결과를 검증, 평가하였으며 부가적으로 실제 발생 가능한 파괴유형 분석을 통하여 현 설치된 수계파이프시스템의 설계에 대한 적절한 내진보강방법에 대하여도 제안하고자 한다.

• 한국화재소방학회논문지
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• 제34권1호
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• pp.47-54
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• 2020

본 논문은 협소공간인 피트 내부에 설치되는 기존 입상관 흔들림방지버팀대의 설치 및 시공 상의 문제점을 개선하고, 수평지진하중(X축, Y축)에 대한 지지역할과 더불어 추가적으로 수직지진하중(Z축)을 지지할 수 있는 협소공간전용 바닥고정형 입상관 버팀대 개발에 관한 연구이다. 솔리드웍스 시뮬레이션을 이용한 구조해석 결과 1차 설계모델의 경우 수직방향에서 앵커 위치에 따른 편심하중이 발생하였고, 수평 및 수직 방향에서 모두 재질의 허용응력을 초과하는 문제가 나타났다. 2차 설계모델의 경우 1차 설계모델에서 발생하였던 수직방향으로의 편심하중에 의한 변형이 발생되지 않았고, 최대변형률이 0.17%로 1차 설계모델(최대변형률 13.01%)보다 약 12.84% 감소하는 것으로 나타나 구조적인 안정성 및 내구성이 향상된 것을 확인할 수 있었다. 시제품에 대한 압축 및 인장 하중시험결과 모든 시제품이 기준에서 정한 성능기준에 적합한 것으로 나타났다.

• Smart Structures and Systems
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• 제8권4호
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• pp.399-412
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• 2011

This study compares the performance of two smart isolation systems that utilize superelastic shape memory alloys (SMAs) for seismic protection of bridges using energy balance concepts. The first isolation system is a SMA/rubber-based isolation system (SRB-IS) and consists of a laminated rubber bearing that decouples the superstructure from the bridge piers and a SMA device that provides additional energy dissipation and re-centering capacity. The second isolation system, named as superelastic-friction base isolator (S-FBI), combines the superelastic SMAs with a flat steel-Teflon bearing rather than a laminated rubber bearing. Seismic energy equations of a bridge structure with SMA-based isolation systems are established by absolute and relative energy balance formulations. Nonlinear time history analyses are performed in order to assess the effectiveness of the isolation systems and to compare their performance. The program RSPMatch 2005 is employed to generate spectrum compatible ground motions that are used in time history analyses of the isolated bridge. Results indicate that SRB-IS produces higher seismic input energy, recoverable energy and base shears as compared to the S-FBI system. Also, it is shown that combining superelastic SMAs with a sliding bearing rather than rubber bearing significantly reduce the amount of the required SMA material.

• Smart Structures and Systems
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• 제17권5호
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• pp.691-708
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• 2016

Recently, number of smart material are investigated and widely used in civil construction and other industries. Present study investigates the application of smart semi-active piezoelectric friction damper (PFD) made with piezoelectric material for the seismic control of the horizontally curved bridge isolated with lead rubber bearing (LRB). The main aim of the study is to investigate the effectiveness of hybrid system and to find out the optimum parameters of PFD for seismic control of the curved bridge. The selected curved bridge is a continuous three-span concrete box girder supported on pier and rigid abutment. The PFD is located between the deck and abutments or piers in chord and radial directions. The bridge is excited with four different earthquake ground motions with all three components (i.e. two horizontal and a vertical) having different characteristics. It is observed that the use of semi-active PFD with LRB is quite effective in controlling the response of the curved bridge as compared with passive system. The incorporation of the smart damper requiring small amount of energy in addition with an isolation system can be used for effective control the curved bridge against the dynamic loading.

• Structural Engineering and Mechanics
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• 제36권3호
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• pp.321-341
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• 2010

The seismic-induced failure of a dam could have catastrophic consequences associated with the sudden release of the impounded reservoir. Depending on the severity of the seismic hazard, the characteristics and size of the dam-reservoir system, preventing such a failure scenario could be a problem of critical importance. In many cases, the release of water is controlled through a reinforced-concrete intake tower. This paper describes the application of a static nonlinear procedure known as the Capacity Spectrum Method (CSM) to evaluate the structural integrity of intake towers subject to seismic ground motion. Three variants of the CSM are considered: a multimodal pushover scheme, which uses the idea proposed by Chopra and Goel (2002); an adaptive pushover variant, in which the change in the stiffness of the structure is considered; and a combination of both approaches. The effects caused by the water surrounding the intake tower, as well as any water contained inside the hollow structure, are accounted for by added hydrodynamic masses. A typical structure is used as a case study, and the accuracy of the CSM analyses is assessed with time history analyses performed using commercial and structural analysis programs developed in Matlab.

• Smart Structures and Systems
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• 제4권2호
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• pp.233-245
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• 2008

For historical masonry structures existing in the Mediterranean area, structural strengthening is of primary importance due to the continuous earthquake threat that is posed on them. Proper retrofitting of historical structures involves a thorough understanding of their structural pathology, before proceeding with any intervention measures. In this paper, a methodology is presented for the evaluation of the actual state of historical masonry structures, which can provide a useful tool for the seismic response assessment before and after the retrofitting. The methodology is mainly focused on the failure and vulnerability analysis of masonry structures using the finite element method. Using this methodology the retrofitting of historical structures with innovative techniques is investigated. The innovative technique presented here involves the exploitation of Shape Memory Alloy prestressed bars. This type of intervention is proposed because it ensures increased reversibility and minimization of interventions, in comparison with conventional retrofitting methods. In this paper, a case study is investigated for the demonstration of the proposed methodologies and techniques, which comprises a masonry Byzantine church and a masonry Cistern. Prestressed SMA alloy bars are placed into the load-bearing system of the structure. The seismic response of the non-retrofitted and the retrofitted finite element models are compared in terms of seismic energy dissipation and displacements diminution.

• 한국공간구조학회논문집
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• 제19권3호
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• pp.33-40
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• 2019

A seismic isolation system is one of the most effective control devices used for mitigating the structural responses due to earthquake loads. This system is generally used as a type of base isolation system for low- and mid-rise building structures. If the base isolation technique is applied to high-rise buildings, a lot of problems may be induced such as the movement of isolation bearings during severe wind loads, the stability problem of bearings under large compression forces. Therefore, a mid-story isolation system was proposed for seismic protection of high-rise buildings. Residence-commerce complex buildings in Korea have vertical irregularity because shear wall type and frame type structures are vertically connected. This problem can be also solved by the mid-story isolation system. An effective analytical method using super elements and substructures was proposed in this study. This method was used to investigate control performance of mid-story isolation system for residence-commerce complex buildings subjected to seismic loads. Based on numerical analyses, it was shown that the mid-story isolation system can effectively reduce seismic responses of residence-commerce complex tall buildings.

• 한국구조물진단유지관리공학회 논문집
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• 제17권1호
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• pp.55-63
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• 2013

본 연구는 우리나라에서 가장 일반적인 중소규모의 비내진 상세를 가진 건축물을 대상으로, 노후도를 고려하여 내진성능을 평가하였다. 평가결과, 준공 후 24년이 경과되었으나 노후도는 대체로 양호한 것으로 평가되었고, 1차, 2차 내진성능평가는 기준지표를 만족하지 못하는 것으로 나타났다. 3차 내진성능평가에서는 층간변위비를 기준으로 목표성능은 만족하지만 보강이 필요한 것으로 판단되었다. 대상 건축물에 벽체보강, 가새보강, 댐퍼보강을 한 후 내진성능평가를 실시한 결과, 보강방법에 상관없이 층간변위비는 현저히 감소하여 즉시거주수준을 만족하는 수준으로 나타났다. 그러나 벽체보강의 경우 밑면전단력이 2배 이상 증가되어 기존기초에 대한 검토가 필요하다.

• 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.

• Smart Structures and Systems
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• 제13권3호
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• pp.375-388
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• 2014

The effectiveness of using the advanced seismic protection technology based on shape memory alloy (SMA) dampers to preserve a historical minaret is investigated. The proposed studied case, the minaret of Mansourah, is a seven century old minaret located in Tlemcen, Algeria. Its original height was of 47m, while nowadays, the monument is half destructed and its current height reaches the 40m. The proposed seismic retrofit is based on the technique that utilizes SMA wires as dampers for the upper flexible part of the minaret. The effectiveness of the proposed technique is numerically evaluated via non-linear finite element analysis using the structural software ANSYS. The effectiveness of the proposed device in mitigating the seismic hazard is demonstrated by the effective reduction in its dynamic response.