• Structural Engineering and Mechanics
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• 제54권2호
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• pp.319-336
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• 2015

Life cycle performance of corrosion affected RC structures is an important and challenging issue for effective infrastructure management. The accurate condition assessment of corroded RC structures mainly depends on the effective evaluation of deterioration occurring in the structures. Structural performance deterioration caused by reinforcement corrosion is a complex phenomenon which is generally uncertain and non-decreasing. Therefore, a stochastic modelling such as the gamma process can be an effective tool to consider the temporal uncertainty associated with performance deterioration. This paper presents a time-dependent reliability analysis of corrosion affected RC structures associated bond strength degradation. Initially, an analytical model to evaluate cracking in the concrete cover and the associated loss of bond between the corroded steel and the surrounding cracked concrete is developed. The analytical results of cover surface cracking and bond strength deterioration are examined by experimental data available. Then the verified analytical results are used for the stochastic deterioration modelling, presented here as gamma process. The application of the proposed approach is illustrated with a numerical example. The results from the illustrative example show that the proposed approach is capable of assessing performance of the bond strength of concrete structures affected by reinforcement corrosion during their lifecycle.

• 콘크리트학회논문집
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• 제22권4호
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• pp.527-534
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• 2010

이 연구에서는 고강도 전단보강근을 사용한 철근콘크리트 보의 부착성능을 향상시키기 위한 간편한 방법을 소개한다. 일반적으로 전단보강근의 항복강도와 보강근비는 철근콘크리트 보의 전단내력에 영향을 미친다. 그러나 철근 콘크리트 보의 부착성능은 보강근의 항복강도에는 큰 영향을 받지 않으므로 고강도 전단보강근을 사용한 경우 부착파괴의 위험성이 있다. 제안된 방법의 구조적 성능을 검증하기 위하여 총 4개의 철근콘크리트 보 실험체를 제작하고 실험하였다. 실험변수는 전단보강근의 항복강도와 보강근비 및 보강형태로 계획하였다. 실험 결과 제안된 방법은 철근콘크리트 보의 부착성능을 효과적으로 향상시킬 수 있음을 확인할 수 있었다.

• 한국방재안전학회논문집
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• 제13권1호
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• pp.13-23
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• 2020

국내 도시철도는 2005년 내진설계가 본격적으로 도입되었으며, 내진성능평가 및 보강방법에 대한 많은 연구가 이루어졌다. 2009년 3월 공포된 지진재해대책법 시행령(현 지진화산재해 대책법 시행령)에 따라 2010년4월~2013년10월까지 일부 지자체에서 도시철도 지하화 구간의 내진성능 상세 평가 및 보강방안을 수립하였다. 그 후, 2018년 말까지 공용기간이 오래된 구간에 대하여 기존 도시철도의 내진성능 평가를 수행하였으며, 기 연구된 방법을 적용하여 다양한 공법으로 보강공사를 시행하고 있다. 그러나 다양한 보강재료과 이를 사용한 공법이 연구되었지만, 현재 도시철도 보강공사에 적용되고 있는 공법에 대한 분류 실태연구는 미비하다. 본 연구의 목적은 현재 도시철도 내진성능보강 공사에 적용중인 사례를 분석하여, 공법별 특징 및 적용 사유와 문제점을 제시하는데 있다.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.114-119
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• 2008

The modern automotive industry develops innovative vehicle designs to meet increasing stability of car and performance demands of their customers. The improvement of frame rigidity by the structural foam is thought to be an effective means to improve the performance because of high applicability and minimum weight. The object of this paper is to examine the use of structural foam in a hat section as an optimum reinforcing means, to compare the reinforcing performance of structural foam versus a plastic reinforcement. The result of this paper indicated that reinforcing efficiencies are achieved by structural foam and plastic reinforcement shape.

• Computers and Concrete
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• 제20권5호
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• pp.511-519
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• 2017

The reliability of reinforced concrete structures is frequently compromised by the deterioration caused by reinforcement corrosion. Evaluating the effect caused by reinforcement corrosion on structural behaviour of corrosion damaged concrete structures is essential for effective and reliable infrastructure management. In lifecycle management of corrosion affected reinforced concrete structures, it is difficult to correctly assess the lifecycle performance due to the uncertainties associated with structural resistance deterioration. This paper presents a stochastic deterioration modelling approach to evaluate the performance deterioration of corroded concrete structures during their service life. The flexural strength deterioration is analytically predicted on the basis of bond strength evolution caused by reinforcement corrosion, which is examined by the experimental and field data available. An assessment criterion is defined to evaluate the flexural strength deterioration for the time-dependent reliability analysis. The results from the worked examples show that the proposed approach is capable of evaluating the structural reliability of corrosion damaged concrete structures.

• 한국안전학회지
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• 제37권6호
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• pp.60-70
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• 2022

This paper proposes an optimal design method of a seismic reinforcement system for the seismic performance of adjacent asymmetric-stiffness structures with viscous dampers. The first method considers plan asymmetry for efficient seismic reinforcement, and evaluates the seismic performance of optimal design applied to two cases of modeling: adjacent stiffness-asymmetric structures and adjacent stiffness-symmetric structures. The second method considers the response of asymmetric structures to derive the optimal objective function, and evaluates seismic efficiency of the objective function applied to two cases of responses: horizontal displacement and torsion. Numerical analyses are conducted on 7- and 10-story structures with a uni-asymmetric-stiffness plan using six cases of historic earthquakes, normalized to 0.4g. The results indicate that the seismic performance is excellent as modeled by adjacent asymmetric-stiffness structures and how much horizontal displacement is applied as the objective function.

• 한국공간구조학회논문집
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• 제22권1호
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• pp.59-66
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• 2022

In this paper, the flexural capacity equation of FRP-bar reinforced concrete beams was verified by comparing the experimental results and flexural capacity obtained according to the ACI procedure. And, also the economic feasibility of FRP-bar reinforced concrete beams was analyzed by comparing nominal moment capacity of beams. The results of analysis were as follows, 1) GFRP concrete beams have lower flexural performance than reinforced concrete beams, whereas CFRP concrete beams have similar flexural performance to reinforced concrete beams under the same reinforcement ratio 2) Although the design moment increased as the compressive strength of concrete increased, the flexural performance of GFRP reinforced concrete beams was found to be lower than the reinforced concrete beams for all reinforcement ratios.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.128-134
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• 2013

High bending collapse performance (maximum resistance force and mean resistance force) of body center pillar is an important design target for vehicle safety against side impact. In this study, effect of the upper section shape and the thickness of outer reinforcement on bending collapse performance was investigated for the center pillar of a large passenger car. First, through bending collapse analyses using simple models with uniform section, an optimized center pillar upper section was chosen. Next, bending collapse performance for various models of the actual center pillar with changing the thickness of outer reinforcement were analyzed. The finally designed model showed distinctive enhancement in bending collapse performance nearly without weight increase.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.201-202
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• 2012

Recently, High-Strength steel reinforcement has been studied throughout the internal and external. One of the advantages using High-Strength steel reinforcement in construction is the economic effect due to the decreasing of its quantity. Also, another good effect is the increases of workability by reason of reducing the congestion. But, realistically it is not used in nuclear power plant construction site because of the restriction of design standard. The purpose of this report secures the reliability and changes the code through the performance evaluation test of the wall using the high-strength steel reinforcement in nuclear power plant.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.53-56
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• 2005

This paper investigates the effect of ductile deformation behavior of high performance hybrid fiber-reinforced cement composites (HPHFRCCs) on the shear behavior of coupling beams to lateral load reversals. The matrix ductility and the reinforcement layout were the main variables of the tests. Three short coupling beams with two different reinforcement arrangements and matrixes were tested. They were subjected to cyclic loading by a suitable experimental setup. All specimens were characterized by a shear span-depth ratio of 1.0. The reinforcement layouts consisted of a classical scheme and diagonal scheme without confining ties. The effects of matrix ductility on deflections, strains, crack widths, crack patterns, failure modes, and ultimate shear load of coupling beams have been examined. The combination of a ductile cementitious matrix and steel reinforcement is found to result in improved energy dissipation capacity, simplification of reinforcement details, and damage-tolerant inelastic deformation behavior. Test results showed that the HPFRCC coupling beams behaved better than normal reinforced concrete control beams. These results were produced by HPHFRCC's tensile deformation capacity, damage tolerance and tensile strength.