서울시 내부순환도로 교면포장 형식에 따른 소음특성 연구

이상염,진정훈,문성호,문학룡 한국도로학회 2012 한국도로학회논문집 Vol.14 No.2

타이어와 포장노면과의 마찰음을 측정하기 위해서 기존 연구를 통해 신뢰성 및 일관성이 검증된 NCPX(Noble Close Proximity) 방법을 이용하여 다양한 교면포장형식에 대해 소음측정을 실시하였다. 또한 이번에 실시한 측정은 표면 마이크로폰을 이용하였다. 서울시 내부순환도로의 교면포장 일부 구간을 대상으로 포장형식에 따라서 소음측정을 하였으며, 4개의 교면포장형식에 대한 소음특성을 평가하는데 적절한 실험법임을 알 수 있었다. 시험결과 소음관점에서 차이가 있음을 확인할 수 있었다. 본 측정을 통해 교면포장 표면조건 및 주행속도에 따라 타이어와 포장노면과의 마찰음이 다르게 나타남을 알 수 있었다. 그리고 1/3 옥타브 밴드 해석을 실시한 결과에 있어 교면포장의 종류에 따라 시공전후로 소음특성이 다른 것을 알 수 있었다. A measuring technique for tire-pavement interaction noise that uses a proposed noble close proximity(NCPX) method, which has been proofed in terms of the reliability and consistency of interaction noise measurement through several researches, equipped with surface microphones has been adopted in order to perform bridge deck pavement noise evaluations on four different pavement surfaces. Through field testing measurement of bridge deck pavement in Seoul inner ring road, the appropriate noise-measuring procedures have been used for evaluating the noise characteristics of four different surfaces. Measuring results show that tire-pavement noise levels vary depending on the surface types and vehicle speeds. Furthermore, the different characteristics of tire-pavement interaction noise can be found before and after the new surface construction of bridge deck pavements in terms of the 1/3 octave band analysis of vehicle speed.

예방적 유지보수 공법의 현장 적용성능 평가 연구

이상염 한국도로학회 2017 한국도로학회논문집 Vol.19 No.2

PURPOSES:In this study, field performance evaluation of crack treatment of pavement and the feasibility of surface treatment of pavement are presented. The performance and cost of preventive maintenance methods have been previously verified, and the methods are being used in many developed countries and cities. However, the performance and cost of the system have not been verified in domestic, field applications. Therefore, in order to improve performance, the field performance is evaluated, and a reasonable cost is proposed.METHODS:Visual Inspection was conducted to evaluate the field application and performance of the preventive maintenance method. In addition, the PCI index was calculated from the results of visual inspection of the application area of the surface treatment method, and the performance life of each method was predicted. For the economic evaluation, life cycle cost analysis was performed using the life cycle cost analysis program.RESULTS:In order to evaluate and quantify the field performance of crack repair material, the residue condition of the pavement surface after crack treatment, rather than the performance of the material, is evaluated. In addition, the crack resistance and performance life of surface treatment methods are evaluated. The cost of currently available treatment methods are compared to the common pavement cut and overlay method, and it is determined that the preventive method is not economical based on life cycle cost analysis.CONCLUSIONS:Because of the characteristics of cracking, it is necessary to conduct the evaluation of currently applied methods and the analysis of the cause of damage, by visual inspection. Moreover, in order to evaluate the performance and economic suitability of the currently applied surface treatment methods, it is necessary to acquire information on application sections by monitoring their long-term conditions and performance.

자치구 포장상태평가등급 기준 개선 및 포장상태 예측지수 개발

이상염,전진호 한국도로학회 2016 한국도로학회논문집 Vol.18 No.6

OBJECTIVES : This study develops an evaluation method, which is useful to inspect pavement condition of specific boroughs. This is because pavement condition is broadly divided into five grades via visual inspection, which does not consider the types of deteriorations, and is decided by an investigator having a subjective viewpoint. This visual inspection method is not a satisfactory method for accurate maintenance when various deteriorations occur. METHODS: The performance model considers several factors such as crack, rutting, and IRI. This method is also modified from borough SPI based on SPI (Seoul Pavement Index). Considering limited budget of borough, PI (prediction index) is suggested, which is related to the grade of pavement condition evaluation and type of materials. Practical correlation review is also conducted with statistical verification by using the Monte Carlo simulation. RESULTS: The results of the study show that modified criteria are reasonable. First, the comparison between the visual inspection result and the SPI result indicates that the R-square value is sufficiently high. Second, through the common section, each evaluation method could be compared, and the result shows considerable similarity, which increases when the range is modified. Finally, PI for predicting remaining life and the random number SPI have common parts, which means that each indicator would be adequate to be used as an evaluation method. CONCLUSIONS : Comparison and analysis results show that the developed evaluation method is reasonable for specific boroughs where financial support is inadequate for the evaluation process by using the newer equipment. Moreover, for more accurate evaluation method, previous visual inspection data should be utilized, and the database of inspection equipment have to be collected.

Effect of Hydrated Lime on Dynamic Modulus of Asphalt-Aggregate Mixtures in the State of North Carolina

이상염,서영국,Y. Richard Kim 대한토목학회 2010 KSCE JOURNAL OF CIVIL ENGINEERING Vol.14 No.6

A comprehensive experimental study has been conducted primarily to characterize the effect of hydrated lime on a dynamic modulus of Hot Mix Asphalt (HMA). In this paper, five Superpave HMAs typically used in the State of North Carolina were modified with hydrated lime and evaluated with a series of uniaxial compressive complex modulus tests. And a new design method was proposed for lime modified HMAs based on their volumetric optimums. For a 9.5 mm surface mixture, three levels of lime addition methods were tested and their impacts on a dynamic modulus and phase angle were statistically analyzed. Finally, a resistance of lime modified HMA to moisture damage was demonstrated by comparing with unmodified HMA. Findings suggested that the inclusion of hydrated lime should make HMAs stiff especially at high frequencies and lower temperatures. The reduction of dynamic modulus due to moisture was smaller in lime modified HMAs than in un-modified HMA.

순환 유동층 보일러 수냉벽 튜브 마모 건전성 평가

이상염,현중섭,명주홍,손종덕 대한기계학회 2023 大韓機械學會論文集B Vol.47 No.2

If the identification of a boiler tube leak in a thermal power plant is delayed, the damage caused by steam and water increases, resulting in an increase in maintenance costs and loss of power generation operation costs. Owing to the characteristics of circulating fluidized bed boilers, the operating temperature is not high compared with that of other thermal power plants. Therefore, the frequency of damage owing to tube deterioration is less, but most tube leakages occur owing to water-wall tube abrasion and refractory damage. If the tube maintenance history and thickness trends are managed, the equipment can be efficiently managed through management plans for weak areas and predicting failures. To this end, a tube maintenance management system was developed. Through maintenance history management and thinning rate calculation, the thinning trend of each tube for the next year was identified, and dangerous parts were selected to evaluate the integrity of tube abrasion. This will provide useful information to engineers to determine the range and interval of plant maintenance. 화력발전소의 보일러 튜브 누설이 발생했을 경우, 고장 파악이 늦어지면 증기와 물에 의한 파급 손상이 확대되어 정비 비용과 발전 운영비용 손실이 증가한다. 순환 유동층 보일러 특성상 다른 화력발전소에 비해 운전온도가 높지 않아 튜브의 열화에 의한 손상 발생 빈도가 적고, 대부분의 튜브 누설은 수냉벽 튜브 마모 및 내화물 손상에 의해 발생한다. 튜브 정비 이력 및 마모 경향을 파악한다면, 튜브 취약부에 대한 관리방안 및 고장 예측을 통해 효율적으로 설비를 관리할 수 있을 것이다. 이를 위해 튜브 정비관리 시스템을 개발하였고, 정비이력 관리 및 감육률 계산을 통해 튜브별 차년도 감육 추세를 분석하고 위험 부위를 선정하여 튜브 마모 건전성을 평가하였다. 이것은 발전소 정비주기, 정비범위를 결정해야 하는 엔지니어에게 유용한 정보를 제공할 것이다.

화력발전소 고장이력을 기반으로 한 터빈 위험도 평가 시스템 개발

이상염,박현구,김영주,박상호 대한기계학회 2019 大韓機械學會論文集B Vol.43 No.2

It is necessary to select suitable plant facilities for overseas power generation projects. Among them, turbines are required to be verified and evaluated during the initial construction. There are specifications, performance, and cost of the turbine that can be evaluated, but there is a need for a method of verifying in terms of risk. In this paper, we developed a model that can show the risk of turbine based on the power plant failure history data, and developed software that can compare and analyze the risk results using it. The developed software can be performed in a short time compared to the quantitative risk assessment, and has the advantage of providing intuitive results. It will provide useful information to engineers who need to determine maintenance cycles as well as overseas power generation users who select turbines. 해외발전사업 수주를 위해 적합한 화력발전소 설비의 선별이 필요하고, 그 중 대표적인 설비인 터빈은 초기 건설시 검증 및 평가가 필수적이다. 터빈의 평가할 수 있는 방법들로 사양, 성능, 비용 등이 있지만, 위험도 측면으로 검증하는 방법이 필요하다. 본 논문에서는 발전소 고장이력자료에 기반하여 터빈의 위험도를 나타낼 수 있는 모델을 개발하고, 이를 사용하여 위험도 결과를 비교/분석할 수 있는 소프트웨어를 개발하였다. 개발된 소프트웨어는 정량적 위험도 평가에 비해 단기간에 수행이 가능하며, 직관적인 결과를 제시하는 장점이 있다. 터빈을 선별하는 해외발전사업 사용자뿐만 아니라 정비 주기를 결정해야 하는 엔지니어에게 유용한 정보를 제공할 것이다.

하모니 검색 알고리즘을 이용한 피로균열의 포장설계 및 유지보수 시기 결정

이상염,문성호 한국도로학회 2014 한국도로학회논문집 Vol.16 No.6

PURPOSES : This research describes how to predict the life cycles of fatigue cracking based on NCHRP Report 704 as well as modifiedharmony search (MHS) algorithm. METHODS : The fatigue cracking regression model of NCHRP Report 704 was used in order to calculate the ESAL (Equivalent SingleAxle Load) numbers up to pavement failure, based on using material parameters, composite modulus, and surface pavement thickness. Furthermore, the MHS algorithm was implemented to find appropriate material parameters and other structural conditions given the number ofESALs, which is related to pavement service life. RESULTS: The case studies show that the material and structural parameters can be obtained, resulting in satisfying the failure endurance ofasphalt concrete structure, given the number of ESALs. For example, the required ESALs such as one or two millions are targeted to satisfy theservice performance of asphalt concrete pavements in this study. CONCLUSIONS : According to the case studies, It can be concluded that the MHS algorithm provides a good tool of optimizationproblems in terms of minimizing the difference between the required service cycles, which is a given value, and the calculated service cycles,which is obtained from the fatigue cracking regression model.

SBR Latex를 이용한 흙 포장의 재료특성 연구

이상염,황성도,양성린 한국도로학회 2014 한국도로학회논문집 Vol.16 No.5

PURPOSES : The purpose of this study is to determine the optimum addition rate of SBR latex through the evaluation of durability andstrength of SBR latex applied soil pavement. Formerly used materials such as fly ash and cement in soil pavement had resulted in decreaseddurability due to micro crack by heat of hydration and shrinkage crack in winter. However, that agglutinated polymers help adhesion toaggregate increased comes up with preventing the crack opening when the number of capillary tubes of SBR latex get decreased in thehydration process of cement. Therefore, in this study, it is suggested that the evaluation of the field applicability of soil pavement be conductedthrough the performance lab test in terms of strength increment, adhesion improvement, and crack resistance based on SBR latex addition rate. METHODS: In order to evaluate the field applicability of soil pavement, SBR latex was added 0 to 3% by 1% increment, with fixed cementcontents of 3% and 5%. The resistance of shear failure and crack of soil pavement were evaluated by performing the uniaxial compressivestrength test and indirect tensile strength test at -20 and 20℃, respectively. RESULTSCONCLUSIONS: It was found out that from both tests, resistance of shear failure and crack were improved with increment ofcuring time, and especially more than 2% of SBR latex addition rate and 5% cement content gave better results.

스마트 그리드와 ICT 인프라 기술동향

이상염,김영현,명노길 한국정보기술학회 2011 한국정보기술학회지 Vol.9 No.2

스마트 그리드는 우리나라를 비롯하여 미국, 유럽, 일본, 중국 등 주요국들이 전략산업으로 추진하고 있다. 나라별로 스마트 그리드 비전에 부분적인 차이점은 있을 수는 있으나 큰 틀에서는 전력인프라의 개선을 통해 전통에너지와 신에너지의 수급과 응용을 최적화하여 에너지 절감을 실현하고, 전력수송의 안정성과 효율성을 제고할 수 있다는 점에서 같다고 할 수 있다. 더구나 에너지와 환경이 중요시 되는 시점인 지금 우리나라에서도 2030년까지 국가단위의 스마트 그리드 완성을 위해 2010년 1월 국가로드맵을 완성하였고, 산업체와 학교, 연구소 등 관련 각 분야에서 필요 기술을 개발하는 등 대대적인 장정에 돌입하였다. 스마트 그리드가 우리나라에서 갖는 특별한 의미는 1차 에너지의 97%를 수입에 의존하고 있어 자원빈국으로 분류되는 여건에서 2차 에너지인 전기는 대부분이 수입 1차 에너지를 변환하여 쓰고 있음을 고려할 때 합리적인 소비가 가능한 시스템을 빨리 만들어 냄으로써 에너지와 환경 문제를 개선하고자 하는 것이 첫 번째 목적이고 두 번째는 전력시스템의 운전을 완전 자동화하여 신뢰성과 효율성을 높이는 것이다. 본고에서는 스마트 그리드에 대한 전반적인 국내외의 동향과 스마트 그리드 ICT 인프라의 기술 동향에 대하여 소개한다.

지표투과레이더 취득신호 분석을 통한 도로하부 이상구간 탐지기법 연구

이상염 한국방재안전학회 2016 한국방재안전학회 학술대회 논문집 Vol.2016 No.-

도로포장 하부 공동 존재여부를 파악하기 위해 하부상태 정보를 획득할 수 있는 지표투과레이더(Ground Penetrating Radar, GPR)가 비파괴시험으로 각광을 받고 있으나 경험에 근거한 정성적 분석으로 인해 정확도는 높지 않다. 정확한 분석 정보와 정량적 해석을 통한 분석기술이 요구된다. 따라서 본 연구에서는 시험구간 (Test bed)에서 GPR 조사로부터 취득한 결과를 분석하여 이상구간을 선정할 수 있었으며, 분석을 위해 심도별 신호의 형상을 중첩시키는 방법과 신호주기에 의한 면적값을 비교하는 방법을 사용하였다 For finding sinkholes, it would be essential to understand cavities under the pavement. GPR is useful to acquire condition information under the pavement because GPR is non-destructive test. However, the accuracy of the test is not high enough. This is owing to the analysis depended on monotonous experiences. It needs improved analysis method with precise assessment and quantitative interpretation. Consequently, this study concentrates on developing several analysis methods by using test bed. To be specific, the obtained signals in test bed are overlapped or piled up for checking abnormal section.