• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 봄 학술발표회 논문집
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• pp.166-173
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• 2002

Seismic bridge failure due to the combined effects of earthquake and local scour are examined in probabilistic perspectives. The seismic responses of multi-span continuous bridge with deep foundations are evaluated with a simplified mechanical model. The probabilistic local scour depths around the deep foundations are estimated by using the Monte Carlo simulation. From the simulation results, it is found that seismic responses of a bridge slightly increase due to the local scour effect. The effect of local scour on the global motion of the continuous bridge is found to be significant under weak seismic intensity. In addition, the duration to regain its original foundation stiffness is critical in estimating the probability of foundation failure under earthquake. Therefore, the duration in recovering the foundation stiffness should be determined reasonably and the safely of the whole bridge system should be evaluated by considering the scour effect.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.376-383
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• 2003

For more rational and economical seismic design of long span bridges, it is essential to include in the analysis the effects of multiple input motions and structural or soil nonlinearity which are not considered in the current design practice. In this paper, the effects of these factors on the seismic behavior of long span bridges are studied. First, for the effect of multiple input motions, we take into account the differences in arrival times of seismic waves. To consider nonlinear soil properties we utilize SHAKE which is based on the equivalent linearization method. As a numerical example, a cable-stayed bridge is modelled using the analytical procedures described above. It is shown from the results that the these factors influence the seismic response of the bridge significantly and should never be neglected in design.

• Structural Engineering and Mechanics
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• 제46권4호
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• pp.505-518
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• 2013

In this study, the seismic performance of a residential building which was damaged in the 1992 Erzincan (Turkey) Earthquake (Ms = 6.8) is performed. Damages on columns due to short columns are estimated analytically implementing the shear hinges and results are compared with the observed damages on the building after the earthquake. In seismic performance evaluation, a deformation based approach is adopted, whereby the structural behavior under external and seismic loads is evaluated. Furthermore, the effects of short columns formed by band windows in basement floors are investigated analytically. The sizes of band windows are parametrically changed in order to understand the effects of short columns on overall building behavior.

• Structural Engineering and Mechanics
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• 제65권1호
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• pp.53-68
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• 2018

In this paper, an innovative procedure is proposed for the seismic design of reinforced concrete frame structures. The main contribution of the proposed procedure is to minimize the construction cost, considering the uniform damage distribution over the height of structure due to earthquake excitations. As such, this procedure is structured in the framework of an optimization problem, and the initial construction cost is chosen as the objective function. The aim of uniform damage distribution is reached through a design constraint in the optimization problem. Since this aim requires defining allowable degree of damage, a damage pattern based on the concept of global collapse mechanism is presented. To show the efficiency of the proposed procedure, the uniform damage-based optimum seismic design is compared with two other seismic design procedures, which are the strength-based optimum seismic design and the damage-based optimum seismic design. By using the three different seismic design methods, three reinforced concrete frames including six-, nine-, and twelve-story with three bays are designed optimally under a same artificial earthquake. Then, to show the effects of the uniform damage distribution, all three optimized frames are used for seismic damage analysis under a suite of earthquake records. The results show that the uniform damage-based optimum seismic design method renders a design that will suffer less damage under severe earthquakes.

• Nuclear Engineering and Technology
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• 제34권6호
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• pp.586-595
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• 2002

The Seismic probabilistic risk assessment (SPRA) or seismic margin assessment (SMA) have been used for the seismic safety evaluation of nuclear power plant structures and equipments. For the SPRA or SMA, the reference response spectrum should be defined. The site-specific median spectrum has been generally used for the seismic fragility analysis of structures and equipments in a Korean nuclear power plant Since the site-specific spectrum has been developed based on the peak ground motion parameter, the site-specific response spectrum does not represent the same probability of exceedance over the entire frequency range of interest. The uniform hazard spectrum is more appropriate to be used in seismic probabilistic risk assessment than the site- specific spectrum. A method for modifying the seismic fragility parameters that are calculated based on the site-specific median spectrum is described. This simple method was developed to incorporate the effects of the uniform hazard spectrum. The seismic fragility parameters of typical NPP components are modified using the uniform hazard spectrum. The modification factor is used to modify the original fragility parameters. An example uniform hazard spectrum is developed using the available seismic hazard data for the Korean nuclear power plant (NPP) site. This uniform hazard spectrum is used for the modification of fragility parameters.

• 한국전산구조공학회논문집
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• 제16권3호
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• pp.321-331
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• 2003

지진취약도분석 기술은 원자력발전소의 구조물 및 기기의 실제 내진성능을 평가하기 위하여 이용된다. 이 논문에서는 원자력 발전소를 구성하는 구조물들의 지진취약도를 평가하는 개선된 기법에 대하여 요약하였다. 또한, 최근 몇 년간 한반도에서 발생된 소규모 기록지진의 응답스펙트럼에 대한 공학적 특성을 평가하고, 이러한 기록지진의 응답스펙트럼을 부지의 실제 지반운동으로 사용할 경우, 지진취약도 분석에 미치는 영향을 검토하였다. 몇가지 예제 구조물에 대한 지진취약도분석을 통하여 기록지진의 특성이 한국형 원자력발전소의 내진성능에 미치는 영향을 정량적으로 평가하였다. 평가결과, 현재까지 부지의 실제 지반운동으로 사용되어 오던 Newmark 스펙트럼은 국내 시설물의 내진성능을 과대평가 할 수 있음을 보여주었다.

• 한국구조물진단유지관리공학회 논문집
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• 제18권5호
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• pp.107-115
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• 2014

본 연구에서는 건물의 질량중심과 면진층의 강성중심 사이의 차이에 따른 면진효과에 대하여 살펴보았다. 면진기술은 면진층에 설치되는 면진장치의 성능에 크게 의존하는 기술이므로 면진장치 제작 후 전수검사를 통하여 면진장치의 수평강성을 검토하게 되어 있다. 하지만 면진장치 성능실험 시 각각의 면진장치의 품질기준은 건축기준에는 정해져 있지 않으며, 이로 인해 설계 시 적용된 강성과 실제 강성의 차이가 발생하여 면진층 상부 부재에 큰 문제를 야기할 수 있다. 연구결과, 최대응답변위의 차이는 크게 나타나지 않았으나 편심이 증가할수록 최대응답가속도, 층전단력 및 상부구조의 부재력은 크게 증가하여 일부 부재에서는 과도한 손상이 예상된다. 따라서 면진층은 실제 장치 제작 후 전수검사를 실시하여 반드시 설계된 의도대로 편심이 발생하지 않도록 장치를 재배치할 필요가 있으며, 가능하다면 건물의 질량중심과 강성중심의 차이는 동일하게 설계할 것을 추천한다.

• 한국공간구조학회논문집
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• 제9권1호
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• pp.69-78
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• 2009

최근의 근단층지반운동인 Northridge 지진(1994, 미국), Kobe 지진(1995, 일본), Izmit 지진(1990, 터키)은 큰 수직성분의 영향으로 건축물 및 교량에 심각한 손상을 주었다. 일반적인 건축구조물의 내진설계에서 지진하중의 수직성분을 고려하여 설계하는 경우는 드물다. 본 연구에서는 지진하중의 수직성분 영향의 고려 유무에 따른 예제구조물의 기둥부재의 축력의 변화와 부재 단부의 소성힌지회전각을 산정하여 시스템의 손상상태를 평가하여 보았다. 해석결과 축력의 증가는 기둥부재의 손상에 의한 전체 구조시스템의 story collapse mechanism의 가능성을 주게 되므로 근단층지반운동이 예상되는 부분에서는 지진하중의 수직성분에 대한 영향을 고려하여야할 것으로 판단된다.

• Earthquakes and Structures
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• 제18권2호
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• pp.201-213
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• 2020

Seismic damages that occurred by the effects of epicenter distance of the earthquake are one of the most important problems for the earthquake engineering. In this study, it is aimed to examine the nonlinear seismic behaviors of concrete gravity (CG) dams considering various epicenter distances. For this purpose, Boyabat CG dam that is one of the biggest concrete gravity dams in Turkey is selected as a numerical application. FLAC3D software based on finite difference method is used for modelling and analyzing of the dam. Drucker-Prager nonlinear material model is used for the concrete body and Mohr-Coulomb nonlinear material model is taken into account for the foundation. Special interface elements are used between dam body and foundation to represent interaction condition. Free-field and quiet non-reflecting boundary conditions are utilized for the main surfaces of 3D model. Total 5 various epicenter distances of 1989 Loma Prieta earthquake are considered in 3D earthquake analyses and these distances are 5 km, 11 km, 24 km, 85 km and 93 km, respectively. According to 3D seismic results, x-y-z displacements, principal stresses and shear strain failures of the dam are evaluated in detail. It is clearly seen from this study that the nonlinear seismic behaviors of the CG dams change depending to epicenter distance of the earthquake. Thus, it is clearly recommended in this study that when a CG dam is modelled or analyzed, distance of the earthquake fault to the dam should be strongly examined in detail. Otherwise, earthquake damages can be occurred in the concrete dam body by the effects of seismic loads.

• 한국지진공학회논문집
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• 제1권3호
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• pp.1-10
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• 1997

구조물 동적거동이 지반과 기초 특성에 따라 영향을 받는다는 것은 인식되었지만, 구조물 내진설계를 위한 설계규준이 지반의 본질적인 복잡성과 기초-지반체계에 대한 체계적인 연구부족으로 지반특성을 부분적으로만 반영하고 있어 불안전하거나 너무 안전한 결과를 초래한다. 이 연구에서는 전단파속도, 지반깊이, 기초 근입깊이 및 말뚝기초의 영향을 평가하여 구조물 내진해석을 위한 기초-지반체계의 운동학적 상호작용 영향을 고찰하였으며, 지반과 기초 특성을 고려한 합리적 내진해석을 위해 지반체계에 대한 수정된 분류기준을 제안하였다. 말뚝기초를 포함한 중형이나 대형 묻힌기초의 경우, 지초-지반체계의 운동학적 상호작용 영향을 고려하기 위해서는 기토밑 지반깊이를 최소한 60m 까지 고려해야하고, 말뚝유무에 관계없이 기초-지반체계의 회전운동도 구조물 내진해석에 포함되어야 한다.