This paper presents the assessment of 7-wire strand monitoring using acoustic emission technique for bridges. 7-wire strand is widely used construction materials to provide additional tensile force to bridges. PSC (PreStressed Concrete) bridge and cable-stayed bridge are representatives for such cases. However, as the bridge aging progresses recently, corrosion problems of strand are emerging. For this reason, various NDT (Non-Destructive Test) methods for cable inspection are being studied and applied to the field. One of the NDT methods, acoustic emission technique, is known as an effective technique to detect cable damage and breakage. In this study, to evaluate the applicability of acoustic emission technique to bridges, acoustic emission signals according to presence or absence of the strand were acquired and analyzed by tensile test. As a result, it is considered that the acoustic emission technique will be able to detect corrosion breakage and signs of rupture.

This paper aims to evaluate the safety of the cable supported bridges under the occurrence of damages on cable system. There are more than 50 cable supported bridges currently built in the Korean peninsula and efficient and systematic maintenance and management are in great demand. However, safety of the bridges cannot be under estimated and should be properly evaluated. In this paper, two bridges (one cable-stayed bridge and one suspension bridge) in South Korea were investigated their safety based on the damage scenario of cable system. FEM analysis for safety evaluation of the two bridges was conducted and the results were explained. The result could be used by operators and owners of bridges for the future maintenance and management.

Airborne chlorides, sulfur dioxide and humidity are the most important causes and acceleration factors of corrosion of the steel member. In this study, such acceleration factors are quantified by analysis of reference data about velocity on corrosion for the determination of durability grade of steel member.

The review of the existing facilities inspection guideline reveals that the dam and river facilities are evaluated mainly by visual and safety inspection. For the efficient maintenance it is necessary to inspect the steel member of the dam and river facilities using the performance-based evaluation method throughout quantitative measurement. In this study durability evaluation index of steel member and evaluation method for the facilities is presented.

The review of the existing facilities inspection guideline reveals that the slope is evaluated mainly by visual and safety inspection. For the efficient maintenance it is necessary to inspect the slope using the performance-based evaluation method throughout quantitative measurement. In this study durability evaluation index and evaluation method for the slope is presented.

The correlation between the degradation scores and service life of the coating is derived by tests and inspection for the coated steel member according to each service environment of several facilities. This correlation called to as the deterioration model can be used to determine the performance grade for the durability of coated steel member of facilities under each service environment, for example, atmospheric, fluvial and marine environment.

국가 전략적 차원에서 전체 사회기반시설물에 대해 미래에 필요한 유지보수 예산 파악하는 것은 매우 중요한 부분이다. 그러나 현 재 국내에서는 전체 대규모 시설물에 적용할 수 있는 유지보수비용 예측 기법이 거의 전무한 실정이다. 본 연구에서는 현재 국내에서 가용한 자 료와 적용 가능한 예측모델을 토대로 우리나라 전체 향후 SOC 시설물에 대한 향후 유지보수 투자 규모를 예측하였다. 실제 지출비용과 비교하 여 가장 적합한 예측모델을 선정하고 관리주체에서 과거에 지출한 유지보수비용 자료를 이용하여 일부 모델은 개발하여 교량, 터널, 포장, 항 만, 댐, 공항, 상수도, 하천, 항만 등의 사회기반시설물에 대한 최적의 미래 유지보수 비용을 산출하였다. 앞으로 10년간 총 비용예측결과, 8종의 사회기반시설물에 대하여 약 23조원이 필요한 것으로 나타났으며, 가장 비용이 크게 발생하는 시설물은 도로포장, 도로교량으로 나타났다.

본 연구에서는 긴병꽃풀의 항산화 효과와 기능성을 활용한 양갱을 제조하여 기계적 특성을 측정하고, 관능적 기호도 평가를 실시하였다. 생리활성 물질의 양을 측정하기 위하여 페놀성 화합물 정량을 실시한 결과 긴병꽃풀 열수추출물에서 12.99±0.30 mg/g, 70% ethanol 추출물에서 3.14±0.07 mg/g으로 나타내었다. 50-200 μg/mL의 농도에서 항산화 효과를 측정한 결과, 전자공여능은 열수추출물과 70% ethanol 추출물에서 각각 77.16-78.24%, 73.04-77.00%로 나타내었으며, ABTS는 84.35-99.75%, 83.74-99.55%로 나타내었다. Antioxidant protection factor(PF)는 1.54-1.62, 1.62-2.09 PF를 나타내었으며, TBARs는 42.93-94.09%, 91.05-95.19%로 나타내었다. 긴병꽃풀 추출물의 열수추출물과 70% ethanol 추출물은 거의 비슷한 항산화 효과를 나타내었으나, PF와 TBARs에서는 70% ethanol 추출물에서 더 우수한 항산화 효과를 나타내었다. Tyrosinase 저해활성은 열수추출물에서는 효과가 나타나지 않았으며, 70% ethanol 추출물에서는 30.32-40.56%의 저해활성을 나타내었다. Hyaluronidase 저해활성은 14.23-40.93%, 57.45-72.88%로 70% ethanol 추출물이 더 우수한 저해활성을 나타내었으며, 50-100 μg/mL의 저농도에서는 positive control로 사용한 PDTC보다 우수한 저해활성을 나타내었다. 색도는 긴병꽃풀 분말의 첨가량이 증가할수록 L 값과 a 값은 감소하는 경향을 나타내었고 b 값은 일정하게 나타내었다. 기계적 조직감은 경도와 탄력성에서 긴병꽃풀 분말의 첨가량이 증가할수록 감소하는 경향을 나타내었고, 응집성은 첨가량과 관계없이 일정한 값을 나타내었다. 씹힘성은 2.0%에서 가장 높은 수치를 나타내었으나 대조군과 첨가군 간의 유의적 차이는 나타나지 않았고, 긴병꽃풀 분말이 양갱의 기계적 조직감에 영향을 준다는 것을 확인할 수 있었다. 긴병꽃풀 분말 첨가 양갱의 관능적 기호도는 점도, 경도, 씹힘성, 탄력성, 맛, 향, 전반적인 기호도 항목에서 대조군을 제외하고 1.0% 이하 첨가군에서 기호도가 높게 나타내었으며 2.0% 첨가군은 모든 항목에서 가장 낮은 기호도를 나타내었다. 위 결과에 따라 긴병꽃풀 분말을 이용한 양갱 제조에는 1.0% 이하의 농도를 사용하여 제조하는 것이 가장 적합하다고 판단되었다.

Numerical analysis was performed to predict for deflection of reinforced concrete (RC) beams in flexure strengthened with textile reinforced concrete (TRC) in this study. TRC is new reinforcing material to strengthen for deteriorated RC structures. TRC consists of fiber reinforced polymer (FRP) reinforcement of textile form and concrete using fine aggregate. This paper presents both results and process of nonlinear analysis method for experimental results published in 2015 by Jung et al. Nonlinear analysis method proposed by Cho et al. was used to predict the displacement at the cross-section of mid-span for RC beams in flexure strengthened with TRC. At the three states of the RC beams such as occurrence of initial flexural crack in tensile concrete, the yield of tensile rebar, and ultimate in accordance with debonding of TRM. Displacements of beams were calculated at the three state and load-displacement curves by predicting results were compared to the collected test results. As a result, nonlinear analysis method accurately predicted the deflection of RC beams strengthened with TRC.

The steel grid composite deck is a composite structure made of a concrete slab disposed over a steel grid. In this study, the punching shear strength obtained experimentally and the shear strength calculated by design equations of ACI 318 and Eurocode 2 are compared. The result shows that the experimental strength is best estimated by the design equation of Eurocode 2 which considers reinforcement ratio.

The review of the existing facilities inspection guideline reveals that the water supply steel pipeline is evaluated mainly by visual and safety inspection. For the efficient maintenance it is necessary to inspect the pipeline using the performance-based evaluation method throughout quantitative measurement. In this study durability evaluation index and evaluation method for the steel pipeline is presented.

Numerical analysis was performed to predict for deflection of reinforced concrete (RC) beams in flexure strengthened with textile reinforced concrete (TRC) in this study. TRC is new reinforcing material to strengthen for deteriorated RC structures. TRC consists of fiber reinforced polymer (FRP) reinforcement of textile form and concrete using fine aggregate. This paper presents both results and process of nonlinear analysis method for experimental results published in 2015 by Jung et al. Nonlinear analysis method proposed by Cho et al. was used to predict the displacement at the cross-section of mid-span for RC beams in flexure strengthened with TRC. At the three states of the RC beams such as occurrence of initial flexural crack in tensile concrete, the yield of tensile rebar, and ultimate in accordance with debonding of TRM. Displacements of beams were calculated at the three state and load-displacement curves by predicting results were compared to the collected test results. As a result, nonlinear analysis method accurately predicted the deflection of RC beams strengthened with TRC.

본 연구는 일반철근과 FRPH Bar를 주철근으로 한 철근 콘크리트 보부재를 대상으로 정적실험 및 반복하중 재하실험을 수행하여 에너지 소산성능 및 반복하중 저항성능을 분석하였다. 실험을 위하여 24MPa의 설계강도를 가진 콘크리트 보부재(200×200×2175mm)를 제작 하였으며, 4점 휨 시험을 수행하여 초기균열하중, 항복하중, 파괴하중을 측정하였다. 정적하중 재하실험을 통해 각 시험체에 대한 항복하중과 파괴강도를 측정하였는데, 항복하중은 RC보에서는 48.9kN, FRPH 보에서는 36kN으로 평가되었으며, 파괴하중은 두 시험체 모두 50kN의 강 도를 보였다. 정적하중-처짐 결과에서는 FRPH 보는 RC보에 비하여 인장경화특성을 나타내는데, 이는 FRPH bar의 인장경화 특성에 기인한다. 반복하중하에서 FRPH bar를 가진 보에서는 일반 RC보와는 다르게 작은 폭의 균열이 넓게 발생하였으며, 우수한 처짐 복원력을 나타내었다. 정적·동적 에너지 비율을 이용한 에너지 소산능력에서는 RC보에서는 0.62, FRPH 보에서는 0.83으로 평가되었으며, 이를 통해 FRPH를 가진 보부재에서 효과적으로 반복하중에 대하여 저항함을 알 수 있다.

In this study, beauty food activities were determined for extracts of Saurus chinensis as functional beauty food. Tyrosinase inhibitory effect was increased as more 4 folds by ultra-fine grind technology than normal grind technology in ethanol extracts from Saurus chinensis. A ultra-fine ground technology was used to increase the extraction yield for bioactive compounds from medicinal plants. Tyrosinase inhibitory activity, which is related to skin-whitening, was confirmed to be 100% for ethanol extracts at 1,000 ppm of phenolics. Anti-wrinkle activity was determined showing 30% of inhibition effect at above 1,000 ppm phenolic concentration. The elastase inhibitory activity of water and ethanol extracts from ultra-fine ground Saurus chinensis showed higher inhibition activity than compared to extracts from normal ground Saurus chinensis. Astringent activity in ethanol extracts was determined showing over 70% at 250 ppm of phenolics. Based on these results, Saurus chinensis extracts can be used as a functional beauty food and cosmetic with whitening, anti-wrinkle and pore contraction effects.

This study was conducted to develop a bended steel-hybrid GFRP (Glass Fiber Reinforced Polymer) bar. The steel-hybrid GFRP bar was to develop for replacing steel rebar for RC structures which were built in the corrosive environment. To be used for RC structures, a bended type of steel-hybrid GFRP bar is required. This study explains the results of current status of the project.

In this research, experiment and simulation plans for evaluating the performance of the cables used for cable-stayed type bridges is presented. 27 cables are prepared where each of the cables are introduced with either corrosion or/and fatigue damage. Then the acquired data is analyzed with the vibration characteristics to evaluate the performance of the cables subjected to the two damage types.

This study was conducted to build an emergency action plan (EAP) for cable-supported bridges in South Korea. First, accidents happened on Cable-supported bridges were investigated and categorized based on the types. Second, accident scenarios were built-up regarding the types. Two bridges were selected for planning the emergency action following the accident scenarios. The emergency action plan established in this study could be used for the management of cable-supported bridges in the future.

Indices are selected for the evaluation of deterioration of coated steel, and an evaluation method is proposed for each index. The evaluation methods proposed in this study are then applied on the existing inspection data measured on site, and the correlation between the resulting evaluation scores and service life of the coating is derived statistically. This correlation called to as the deterioration model can be used to determine the performance grade for the durability of coated steel.

Development of performance evaluation method per unit facilities for the performance-based management·operation of the port facilities defined in the accounting process guideline for SOC facilities and verification of the practicability of the developed method.

This paper introduces unfamiliarity index (UFI) that calculated from the FFT results of the short term timeline acceleration responses. If this algorithm, which can detect an abnormal behavior from the maximum constant signal, is used to the terminal sensors of an structure, more accurate safety control criteria will be prepared efficiently.