• Structural Engineering and Mechanics
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• 제70권6호
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• pp.781-791
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• 2019

Earthquakes most often induce damage to structures, resulting in the degradation or deterioration of integrity. In this paper, based on the experimental study on 5 RC frames with different span length and different layout of buckling-restrained braces, the seismic damage evaluation law of RC frame with buckling-restrained braces was analyzed, and then the seismic damage for different specimens was calculated using different damage models to study the damage evolution. By analyzing and comparing the observation in test and the calculated results, it could be found that, damage evolution models including Gosain model, Hwang model as well as Ou model could better simulate the development of damage during cyclic loading. Therefore, these 3 models were utilized to analyze the development of damage to better demonstrate the evolution law for structures with different layout of braces and under different axial compression ratios. The results showed that from all layouts of braces studied, the eccentrically braced frame behaved better under larger deformation with the damage growing slowly. It could be deduced that the link beam benefited the seismic performance of structure and alleviated the damage by absorbing high values of energy.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1638-1653
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• 2024

Given the unpredictability of the occurrence of the earthquake and other potential disasters into consideration, the nuclear power plant may be confronted with beyond design-basis earthquake load in the future. The containment structure may be severely damaged under such severe earthquake loading, increasing the risk of containment concrete cracking and potential radioactive materials leaking. Moreover, initial damage caused by the earthquake may significantly alter the pressure performance of the containment under follow-up internal pressure. To compromise the dangers of beyond design-basis earthquake to the containment, an alternative of replacing the conventional concrete with fiber-reinforced concrete (FRC) to upgrade the seismic resistance capacity of the containment is attempted and thoroughly researched. In this study, the influence of various fiber types such as rigid fiber and mixed fiber is regarded to constitute fiber-reinforced PCCVs. The physical properties of traditional and fiber-reinforced PCCVs under earthquake ground motions are scientifically compared and identified by using traditional and proposed evaluation indices. The results indicate that both the traditional evaluation index (i.e. top displacement, stress, strain) and the proposed damage index are greatly reduced by the practice of fiber strengthening under earthquake ground motions.

• 화약ㆍ발파
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• 제21권4호
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• pp.1-10
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• 2003

연암평가는 굴착난이도 평가와 관계가 많은 것을 고려할 때 굴착과 관련되는 발파와 연관 지울 수 있다. 따라서 현장에서 소량의 화약을 사용하여 누두공시험에 의해 구해진 누두지수와 발파계수를 연암의 분류요소로 사용하기 위한 시도가 이루어 졌다. 또한 현지 지반의 탄성파속도와 암석의 파쇄에 대한 저항성 나타내는 Protodyakonov의 계수도 분류요소로 사용하여 연암의 분류를 실시하였다.

• Steel and Composite Structures
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• 제1권3호
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• pp.283-294
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• 2001

In the present work a constitutive model is developed which permits the assessment of the structural performance through a criterion based on cumulative damage. For it, a damage index is defined and is evaluated through the application of the Miner's rule in low-cycle fatigue. However, the damage index is not considered as a posteriori variable since is incorporated explicitly as an internal variable in the constitutive equations which produces a direct coupling between the damage and the structural mechanical behaviour allowing the possibility of considering as a whole different coupled phenomena. For the elaboration of this damage model, the concepts of the mechanics of continuum medium are applied on lumped dissipative models in order to obtain a coupled simplified model. As a result an elastoplastic model coupled with damage and fatigue damage is obtained.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.308-315
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• 2002

Fragility analysis is widely used for the seismic safety evaluation of a structure. In fragility analysis, damage evaluation is a crucial factor. Most of the present fragility analyses use the representative responses such as displacement and absorbed hysteretic energy as a tool of damage evaluation. But damage evaluation method that can represent the local damage of a structure is required in the case of piers of which the local damage can cause the whole failure of bridge system. Therefore this study proposes a damage index, which can represent the distribution and magnitude of local damage by using the Lee and Fenves'plastic-damage model. Using the proposed damage index, fragility curves and damage probability matrix of pier are produced and fragility analysis is performed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1246-1249
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• 2009

Liquefaction hazard caused by earthquake is the damage in a wide range. Until now, liquefaction hazard potential at a small area or most structure in Korea was assessed by modified Seed & Idriss method. However, it has been known that this method is not proper for metropolitan area due to a lot of time and data to perform the related ground response analyses such as Shake program. For these reasons, the current method has been used facilities or structures, not metropolitan area. In this study, several contents in seismic design of Eurocode and Korean seismic design standard for Port and Harbor were introduced and applied for assessing the liquefaction potential and mapping the liquefaction hazard by LPI(Liquefaction Potential Index). Finally, Ulsan metropolitan city was practically drawn in two dimensional space.

• Structural Engineering and Mechanics
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• 제45권2호
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• pp.211-232
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• 2013

In this study a multi-objective optimization problem is solved. The objectives used here include simultaneous minimum construction cost in term of sections weight, minimum structural damage using a damage index, and minimum non-structural damage in term of inter-story drift under the applied ground motions. A high-speed and low-error neural network is trained and employed in the process of optimization to estimate the results of non-linear time history analysis. This approach can be utilized for all steel or concrete frame structures. In this study, the optimal design of a planar eccentric braced steel frame is performed with great detail, using the presented multi-objective algorithm with a discrete population and then a moment resisting frame is solved as a supplementary example.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.200-207
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• 2003

The seismic behaviors of steel moment connections are investigated based on the numerical analysis of the connections with US and Japanese typical details. The rupture index, representing the fracture potential, is used to evaluate the ductility of the connections at the critical location. The results show that the presence of a slab increases the beam strength, imposes constraint near the beam top flange, and consequently, induces concentrated deformation near the beam access hall, which reduces the ductility of the connection. The total deformation capacity of the connection depends not only on a beam but also on a column and panel zone.

• Earthquakes and Structures
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• 제11권3호
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• pp.421-443
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• 2016

When conducting seismic assessment of an asymmetric building, it is essential to carry out three-dimensional analysis considering all the possible directions of seismic input. For this purpose, the author proposed a simplified procedure is to predict the largest peak seismic response of an asymmetric building subjected to horizontal bidirectional ground motion acting in an arbitrary angle of incidence in previous study. This simplified procedure has been applied to torsionally stiff (TS) asymmetric buildings with regular elevation. However, the suitability of this procedure to estimate the peak response of an asymmetric building with vertical irregularity, such as an asymmetric building with setback, has not been assessed. In this article, the pushover-based simplified procedure is applied to estimate the peak response of asymmetric buildings with bidirectional setback. Nonlinear dynamic (time-history) analysis of two six-storey asymmetric buildings with bidirectional setback and designed according to strong-column weak beam concept is carried out considering various directions of seismic input, and the results compared with those estimated by the proposed method. The largest peak displacement estimated by the simplified method agrees well with the envelope of the dynamic analysis response. The suitability assessment of the simplified procedure to analysed building models is made as well based on pushover analysis results.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.343-346
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• 2005

Earthquake resistance design has been developed many countries like Japan, USA, Mexico, New Zealand etc., which countries have experienced many earthquakes. Nowadays, earthquake resistance design has come into worldwide use. In Korea, the seismic design regulations have been established since 1988 in order to minimize the economic losses. Recently performance based design method has been adopted as a new Earthquake resistance design method. These regulations, however, are targeted for newly constructed buildings, In Korea, there are no regulations for existing buildings that built before 1988. So, we need to prepare the regulations that evaluate the seismic performance, furthermore proper retrofitting design guideline needs to be proposed when remodeling old buildings. This study was performed that many existing apartments is being a Remodeling object when considering the present condition of existing apartment and the problems of cost and environment in the future plan. When Remodeling construction is reviewed by former the Seismic Performance Evaluation Method, generating problems is evaluation by using Push-over. According to this, it provides the appropriate method of calculating the Seismic Ship Performance Index.