• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.6
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• pp.70-76
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• 2019

This paper presents a methodology for priority decision of performance evaluation of small-and-medium-sized highway bridges. This methodology could be used for establishing a maintenance strategy of those bridges which are not liable to the law of the Special Act on the Safety Control and Maintenance of Establishments and are thought laid under blind spot. The risk index are calculated considering vulnerability and social influence, then the bridges are classified as three types, one requiring immediate evaluation, the other one requiring evaluation within next year, and the third one observing, according to the index. The suggested method was applied to a small bridge under service and its field applicability verified. From this study, it was judged that this methodology could be used appropriately for establishing maintenance strategy and saving the maintenance budget.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.161-168
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• 2021

This paper is a maintenance system for bridge represented by Class 3 and other than by law bridges. Domestic bridge are divided into Class 1 & 2 bridges and Class 3 & other than by law bridges. The number of type 3 and other than by law bridges is very large. But, it is considered to be of relatively low importance compared to Class 1 & 2 Bridge Bridge. So, in this paper is propose a maintenance system and procedure for small & medium-sized bridges. However, because the number of small & medium-sized bridges is large, it is not possible to evaluate the performance of all bridges like Class 1 & 2 bridge. The reason is the lack of manpower and budget. Based on the Risk Matrix method, a maintenance procedure was created to select the bridge for which performance evaluation should be performed first. For this purpose, basic information of the bridge is used. And, the developed maintenance procedures were applied to the bridges in actual use.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.1-11
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• 2021

As the aging of large domestic SOC facilities accelerates, facility maintenance is also changing from safety evaluation based on the current condition to performance-oriented preventive and preemptive maintenance based on the prediction of the level of future obsolescence. In particular, in the case of bridges, class 1 and 2 bridges are systematically managed along with many studies, but for small and medium-sized class 3 bridges there is no collection and utilization of historical data presenting performance degradation during their service life. Therefore, in this study, 3D model-based demonstration DB system was designed and developed to intuitively check the damage change rate at the damage location by registering the maintenance history by life cycle for each member's exterior damage in the 3D bridge object and to enable API-based comprehensive performance evaluation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.67-74
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• 2019

In this paper the response factor is investigated for middle and small size-RC slab aged bridges. The response factor consists of static and dynamic response factors and is a main parameter in the frequency based-bridge load carrying capacity prediction model. Static and dynamic response factors are determined based on the frequency variation and the impact factor variation respectively between current and previous (or design) states of bridges. Here, the impact factor variation is figured out using the impact factor response spectrum which provides the impact factor according to the natural frequency of bridges. In this study, four actual RC slab bridges aged over 30 years after construction are considered and their span length is 12m. The dynamic loading test in field using a dump truck and eigenvalue analysis with FE models are conducted to identify the current and previous (or design) state-natural frequencies of the bridges, respectively. For more realistic considerations in the moving loading situation, the impact factor response spectrum is developed based on tri-axle moving loads representing the dump truck load distribution and various supporting conditions such as simply supported and both ends fixed conditions. From the results, the response factor is widely ranged from 0.21to 0.91, showing that the static response factor contributes significantly on the results while the dynamic response factor has a small effect on the result. Compared to the results obtained from the impact factor response spectrum based on the single axle-simply supported condition, the maximum percentage difference of the response factors is below 3.2% only.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.581-584
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• 2003

Recently, construction industry has an interest on the maintenance area of construction facilities to maximize utilization of the each facility. This study suggests an interactive electronic technical manual for bridge facility to improve quality and to ensure safety of the bridge facility. The improvement method of bridge maintenance system consists of the basic information ell the facilities, maintenance manuals and measurement system. And the suggested system is based on the facilities, maintenance manuals and measurement system. And the suggested system is based on IETM (Interactive Electronic Technical Manual), and this study defines and develops a $BF\_IETM (Bridge Facility\_ITEM$ as the bridge maintenance system.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.521-521
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• 2012

우리나라는 산악지역이 국토의 대부분을 차지하고 있어 전체유역을 놓고 볼 때 대하천이 차지하는 부분보다는 중소하천이 차지하는 부분이 상대적으로 크고, 교량의 길이가 짧은 소교량이 수적으로 많은 부분을 차지하고 있다. 그중에서도 특히 중소하천의 유량은 시간적으로 매우 빠르게 변화하며 유속 또한 급속히 빨라져 하상의 변형이 순식간에 일어나고 있다. 이와 같은 시간적, 공간적인 호우특성과 지형특성으로 인하여 중소하천에 위치한 교량은 특히 세굴에 매우 취약함을 보여주고 있다. 하천에 건설되는 교량의 수명이나 안정성에 세굴이 미치는 영향은 매우 크며, 특히 우리나라와 같이 홍수 시 단기간에 걸쳐 유량이 급증하는 경우 유속에 의한 교량 기초의 급격한 세굴은 예상치 못한 교량 붕괴 사고를 초래할 수 있다. 현재 국내 소하천에 설치된 교량은 약 3,470개소(지방도 기준)로 다양한 하부구조로 설계되어 있다. 이렇게 하천 내에 세워진 교량과 같은 횡단 구조물들은 그 크기에 상관없이 하천의 형태에 영향을 미치게 된다. 그중에서 교량 세굴은 하천 횡단구조물로 인하여 발생되는 가장 중요한 문제 중의 하나로써 교량 건설 시 교각에 영향을 주는 세굴을 예측하고 방어하기 위하여 다양한 방정식을 통하여 신설교량의 교각세굴을 예측한다. 하지만 대부분의 교량 세굴 공식들은 실험실에서의 실험 결과를 토대로 개발되었기 때문에 이들 공식들이 산정한 국소 세굴량이 얼마나 정확한지는 실제 현장 관측 자료와의 비교를 통해서만 검증할 수 있다. 세굴 공식들의 산정 결과를 현장 실측자료와 비교하는 연구는 그 동안 다양하게 시도되었으나, 통일된 결론에는 도달하지 못하고 있다. 본 연구에서는 기존의 세굴깊이 산정 시 일반적으로 사용되어지고 있는 세굴공식들 중 소하천 교량 규모에 적용 가능한 공식들을 선별하고, 각 세굴심 추정공식에 속한 변수별 특성분석을 위하여, 5가지의 독립변수를 설정하여 국부세굴의 현장 측정값과 예측공식의 비교결과에 대하여 불일치율을 비교분석하였다. 그 결과, 모든 공식들의 불일치율의 기하 평균이 1보다 큰 것을 보여주고 있다. 즉, 모든 공식들이 과대 추정의 의미로 정확성면에서 우수한 공식들은 불일치율의 기하 평균이 1에 가깝고 기하 표준편차가 작은 공식들이 나타났으며, 이런 점에서 Froehlich 공식, Inglis-Poona II, Blench-Inglis I, Breusers 공식 등의 기하평균이 1에 가장 근접한 결과를 나타내었다. 각 세굴공식 세굴심 산정결과의 불일치율을 각각 5가지의 변수별로 도시하여 분석하였으며, 그 결과로 소하천에 대하여 적용 가능한 공식과 소하천에 적용 시에는 과다추정의 우려가 있는 공식으로 분류되어 면밀한 검토가 필요할 것으로 판단된다.

• Journal of Korean Society of Disaster and Security
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• v.12 no.3
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• pp.51-57
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• 2019

In recent years, the occurrence of localized torrential rain has increased due to the increase in heavy rainfall and massive typhoons caused by abnormal weather. As a result, the flow rate of small and medium-sized rivers in Korea is rapidly increasing, affecting the safety of bridges and increasing the risk of scour. However, the domestic bridge construction technology does not reflect the watershed characteristics of domestic rivers because the bridge scour depth calculation formula developed overseas is used to calculate the bridge scour depth. Therefore, this study is a basic study for prevention of bridge damage according to scouring phenomenon, and a comparative analysis was performed between the experimental data measured through hydraulic model test and the scour depth formulas applied in Korea. In addition, the statistical analysis between experimental data and scour depth formula shows that Coleman's (1971) formula estimates the best scour depth. The results of this study are expected to be used to calculate more accurate bridge scour depth in river design and bridge design.

• Journal of Korean Society of Steel Construction
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• v.14 no.5 s.60
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• pp.603-612
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• 2002

Numerical analyses have been carried out in order to check the applicability of high-strength steel to a medium-sized steel bridge. Using the yield strength of steel, Average Daily Truck Traffic (ADTT), and fatigue grade of structural detail as analytical parameters, the minimum weight sections that satisfy the limit states of the AASHTO LRFD design specification were determined through an optimization scheme. Likewise, the effects of the number of girders and span length on the applicability of high-strength steel were evaluated. Results show that high-strength steel may be employed in the steel bridge, since steel weight decreases with increasing yield strength regardless of the fatigue effect. Nonetheless, appropriate countermeasures against fatigue should be determined since it is a major factor in the effective use of high-strength steel in steel bridges.

• Journal of Korean Society of Steel Construction
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• v.22 no.3
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• pp.209-218
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• 2010

The fatigue phenomenon, which is induced by stress accumulation due to the repeated loading of vehicles in the long term, is one of the main factors of the span of life of a steel bridge. In this paper, the effects of traffic properties on the fatigue life of ordinary short- and medium-span steel plate girder bridges that are exposed to relatively large dynamic effects are investigated. From the analysis, it was known that the fatigue life of the bridge becomes shorter with increasing traffic volume and number of large vehicles, and is affected by the weights of the vehicles. Based on the analysis results, a new parameter that can represent the traffic property that affects the fatigue life of the subject bridge is suggested, and the validity of the parameter is confirmed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.146-154
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• 2011

Recently, the paradigm of social infrastructure investment has been changed from new construction to maintenance and management. As a consequence, the management and maintenance system of existing highway facilities needed an innovation involving the concept of asset management. This paper discusses the new facility management system suitable to local highway agencies. The new system incorporates asset management concept so that it can analyze the network level facility management solution and it can also improve the budget efficiency for local government. This paper also presents systematic method to integrate various facilities for management system.