지진취약도 분석은 원자력 발전소의 내진성능평가를 위하여 발전되어져 왔지만, 현재는 적용성이 건물과 교량 등에도 확대되어지고 있다. 일반적으로 지진취약도 곡선은 수많은 지진가속도 기록을 이용하여 비선형 시간이력해석으로 구한다. 비선형 시간이력해석에 의한 지진취약도 분석은 구조물의 모델링과 해석에 많은 시간이 소요되는 과정을 요구한다. 비선형 시간이력해석의 이와 같은 약점을 보완하기 위해서 변위계수법과 역량스펙트럼 방법과 같은 간단한 해석방법을 지진취약도 분석에 적용하였다. 변위계수법과 역량 스펙트럼 방법을 적용한 지진취약도 곡선의 정확성을 평가하기 위하여, 철근콘크리트 전단벽 구조물에 대한 변위계수법과 역량스펙트럼 방법을 적용한 지진취약도 곡선을 비선형 시간이력해석에 의해 구해진 지진취약도 곡선과 비교하였다. 지진취약도 곡선의 작성을 위해서는 설계스펙트럼에 대응되는 190개의 인공지진과 Shinozuka 등이 제안한 방법이 적용되었다.

Chitin was isolated from crab shells by modified Hackman's method, which was treated again with aqueous sodium hydroxide solution to give alkali chitin(sodium alkoxide of chitin). And after, the alkali chitin is allowed to react with monochloroacetic acid to synthesize 6-O-(carboxymethyl) chitin [CM-Chitin] under diminished pressure. In order to synthesize high performance CM-Chitin as hygroscopic agent, it was measured that the yield and degree of subsititution of each CM-Chitin according to molar ratio(monochloroacetic acid equivalent mol/N-acetyl-D-glucosamine residue) and their moisture-absorption and moisture-release properties were measured and compared with those of hyaluronic acid. The moisture-absorption and moisture-release properties of CM-Chitin, especially 0.8 in degree of substitution, were found quite similar to those of hyaluronic acid. The preliminary results show that CM-Chitin might be used as hygroscopic agent instead of hyaluronic acid in field of cosmetics.

교량에서의 후설치 앵커는 시공 중 또는 유지관리시 주요 부재 또는 부대시설의 설치를 위하여 제한적으로 적용되고 있다. 본 고에서는 후설치 앵커를 적용한 대표적인 사례 중 하나인 교량 점검시설의 설계와 시공 사례를 소개한다. 지금까지 교량의 점검시설은 하부구조와 상부구조 콘크리트가 경화된 이후에 앵커 구멍을 뚫은 후 앵커를 고정하는 방식으로 앵커 시스템이 구성된다. 따라서 이러한 시공 과정을 고려하여 설계하고, 시공하게 된다. 그러나 실 교량에서 콘크리트 부재에는 철근이 배치되어 있고, 표면 또한 요철이 있는 경우가 있으며, 작업 여건이 양호하지 않기 때문에 부적절한 시공 사례도 빈번 하게 나타난다.

본 연구진은 메틸말리올라이드가 인간 피부 세포주인 HaCaT 세포에서 NRF2를 유도하고 이를 통하여 항산화 효과를 나타내는지 알아보았다. MTT assay를 통하여 메틸말리올라이드는 10 μ M 농도에서 24 h 동안 HaCaT 세포에 처리하여도 HaCaT 세포 독성을 나타내지 않는 것을 확인하였다. 본 연구진이 구축한 HaCaT-ARE-GFP-luciferase 세포에 메틸말리올라이드를 처리하고 루시퍼라아제 활성을 측정한 결과 메틸말리올라이드는 양성 대조군인 레스베라트롤보다 ARE 결합에 따른 루시퍼라아제 활성을 더욱 강하게 증가시키는 것을 확인하였다. 또한 HaCaT 세포에 메틸말리올라이드 처리 시 NRF2에 의하여 유도되는 항산화 단백질인 HO-1과 NQO1 mRNA 및 단백질 발현이 통계적으로 유의하게 증가하였다. 마지막으로 메틸말리올라이드는 HaCaT 세포에서 TPA에 의해서 유도된 DNA 및 지질의 산화를 강력하게 억제하였다. 결론적으로 본 연구는 메틸말리올라이드가 NRF2 유도를 통하여 피부 산화적 스트레스를 억제하며 이는 메틸말리올라이드가 신규 항산화 화장품의 소재로 적합하다는 것을 시사한다.

There are more than 9,300 bridges on the highway, of which about 34%(3,150) are PSCI bridges. The safety of these bridges is directly influenced by the tensile strength of the internal tendons(strand) and the strength of the concrete compared to the reinforcing bars from the design viewpoint. Therefore, in this paper, for the maintenance plan considering the damage of the internal tendons, the internal tendon cutting and truck loading test was conducted and deflection and appearance status change was analyzed. As a result of the test, deflection increased and flexural cracks occurred on center of the girder. And longitudinal direction cracks followed tendon placement occurred on a bottom flange.

In this study, the severing tests of prestressing steel in old PSCI bridges were carried out. The behavior of the bridge is investigated by measuring the displacement and strain at midpoints of severing girder. The effects of severing some prestressing steel were not noticeable enough to be visible.

Recently, there has been frequent shortage of expansion joint in expressway bridges. When that happens, maintenance budgets will be overloaded and not effective, so it is not easy to come up with a solution. In this study, we introduce a bridge inspection system that combines laser image sensing technology and automatic control technology, which have been recently applied in various fields. And this system was developed to measure bridge extension joints while traveling 100km/h.

In this study, the grouting condition and the corrosion of prestressing steel in old PSCI bridges were investigated. There are many places where the construction quality of the grout is poor to prevent the corrosion of prestressing steel. Partial surface corrosion was found regardless of the construction condition of the grout.

Post-tension system was applied most PSC bridges in Korea. Also Grouting was applied to prevent corrosion of the strand. For this reason, it is difficult to inspection the condition of the strand after completion. Therefore, in this paper, the Nondestructive testings(NDTs) developed at domestic and foreign was investigated. In addition, the current level and limit of the NDTs were analyzed considering the existing bridge environment. As a result of the study, Strand condition inspection using NDTs have been analyzed to have technical and environmental limitations.

In this paper, about 300 ground anchors which was long-term loss of tensile force occur were investigated and analyzed to determine (a)the magnitude of the load loss, (b)the causes and countermeasures of long-term loss of tensile force of ground anchors

Recently, there has been frequent shortage of expansion joint in expressway bridges. When that happens, maintenance budgets will be overloaded and not effective, so it is not easy to come up with a solution. In this study, we introduce a bridge inspection system that combines laser image sensing technology and automatic control technology, which have been recently applied in various fields. And this system was developed to measure bridge extension joints while traveling more than 80km/h.

The bridge coping part may cause cracking due to over-loading of superstructures. And the external prestressing method is a typical reinforcement method for a crack of coping. However, in case of design and construction error, it is difficult to expect sufficient reinforcement effect and reinforcement coping part may be damaged. For this reason, in this paper, The damage case of the coping with external prestressing method was introduced and the cause of the damage of anchorage zone was analyzed. As a result of the analysis, the cause of the damage of the anchorage zone was due to the shortage of bolt anchorage length. Also, as a result of simple calculation, the anchorage length of the bolt did not satisfy the pullout force that was occurred by the moment.

This study introduces abnormal noise phenomenon of steel deck plate bridge which have not been mentioned in the literature or reports. The abnormal noise occurred from the time when the girder was installed and the welding was completed. And it had continued after the bridge opened. In this study, firstly, the characteristics of abnormal noise is analyzed. Also it presents the mechanism of noise generation.

The cause of the falling of the girder of a PSCI bridge under construction was investigated to prevent from similar accidents. The I-type bridges are the most unstable phase after the girder construction and before the installation of concrete slab. Generally the bridges are taken into consideration in order to secure stability in the construction process. However, this bridge was found to have fallen in a rainy and strong wind with some neglect of the procedures and methods presented in the design.

Recently, there has been frequent shortage of expansion joint in expressway bridges. When that happens, maintenance budgets will be overloaded and not effective, so it is not easy to come up with a solution. In this study, we introduce a bridge inspection system that combines laser image sensing technology and automatic control technology, which have been recently applied in various fields. And this system was developed to measure bridge extension joints while traveling more than 80km/h.

Recently, there has been frequent shortage of expansion joint in expressway bridges. When that happens, maintenance budgets will be overloaded and not effective, so it is not easy to come up with a solution. In this study, we introduce a bridge inspection system that combines laser image sensing technology and automatic control technology, which have been recently applied in various fields. And this system was developed to measure bridge extension joints while traveling more than 80km/h.

The maintenance costs will be increased due to the aging of the bridge. Most of maintenance activity is generally known for preventing and repairing the deterioration by de-icing salts. The objective of this research is to investigate the minimizing strategy of maintenance costs for the deterioration by de-icing slats of highway bridges.