• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.521-524
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• 2003

This paper is aimed to develop the circuit of a coil-type oil sensor packaged to the automotive engine oil monitoring the deterioration in the driving condition and let a driver notify the optimized time for the exchange of engine oil. By applying the principle which the deterioration of automotive engine oil can be expressed to the dielectric constant, the capacitance bridge circuit and the integrator circuit are designed and packaged to a coil-typed engine oil. In this study. the range of operating temperature of engine oil is experimentally recommended within 55$^{\circ}C$ for the stability of a sensor designed. It is concluded that the characteristics of output voltage converted from the dielectric constant are linearly distributed.

• Magazine of the Korea Concrete Institute
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• v.18 no.3 s.92
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• pp.42-50
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• 2006

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.17 no.2
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• pp.36-44
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• 2013

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.255-266
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• 2000

Since 1993, Seohae grand bridge has been continued construction for 7 years and will be completed late this year. The bridge is a part of west sea castal highway and consists of 3 types of bridge including precast segmental method, free cantilever method and cable stayed bridge. A cable stayed bridge is the core of this bridge and it consists of 5 span, symetrical cable-stayed bridge with a total length of 990 m. The main span between two H-shaped pylons extending approximately 180 M above massive foundation of a cable stayed bridge is 470 m long and an approach span of that is 260 m long respectively. The circular cofferdam with 16 ea of 25 m diameter flat type sheet pile had been applied to construct foundation. The slipform method had been applied for forming of con'c of two H-shaped pylons with 3 cross beams respectively which is varied horizontally and vertically. The deck has been erected with balanced cantilever method using movable derrick crane. The stay cables is a bundle of parallel individually protected, 7 wire high tensile strands. The strands is hot deep galvanized and sheathed with a tight high density polyethylene coating. A petroleum wax fills all the inter-wire voids. The bundle of strands to prevent from deterioration due to the ambient problem covered with high density polyethylene pipe. The Isotension method has been applied for the stressing of cable strands to ensure uniformity of force in all the strands of a syay and such works has been performed on the stay specially provided in the pylon.

• Journal of the Korean Society of Safety
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• v.24 no.4
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• pp.53-58
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• 2009

The importance of process for repair and reinforcement of the bridge is increasing because of the lack of the fatigue load and stress, a lowering of the bridge load carrying capacity owing to impact and oscillation, deterioration on cultivation periods of the bridge, etc. Typically the experimenter values the bridge load carrying capacity by the real rating factor and response modification factor in bridge load rating through static load test and dynamic load test. But the error occurred in reliability of response modification factor in bridge load rating according to experience of experimenter. so tests of connecting probability theory and valuation of the bridge recently. The study is to compute the real load carrying capacity of the bridge and the rating factor and response modification factor on grade of the bridge, and calculate the probability of over-loaded truck load from Weigh In Motion(WIM) Data in FORTRAN programming applying to Monte-Carlo Simulation. At the result of this study, it is acquired that the new grade is computed for the probability of over-loaded truck load and surface inspection. The A grade is over 1.95, B grade is $1.55{\sim}1.94$, C grade is $1.26{\sim}1.54$, D grade is $1.14{\sim}1.25$, E grade is under 1.13 of rating factor, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.355-358
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• 2005

Corrosion of reinforced concrete structures in marine environment is one of the most important mechanisms of deterioration. Under Korean highway bridge, the time for the steel reinforcement in the concrete to exhibit initial signs of corrosion is within three decades. Therefore, 'SUM JIN' highway bridge, located in a corrosive marine environment on the south of Korea, had been examined the current condition of the steel reinforcement corrosion in concrete by half-cell potentials, chloride contamination of concrete and so on. According to the tests, the protecting film around the reinforcement is deteriorated and corrosion activity developed in tidal zone. The purpose of this paper is to report the effects of 'SUM JIN' highway bridge damaged by chlodide attack and to present the results of repair of 'SUM JIN' highway concrete bridge in domestic marine environment.

• Smart Structures and Systems
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• v.21 no.3
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• pp.305-320
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• 2018

The second half of the 20th century was marked with a significant raise in amount of railway bridges in Austria made of reinforced concrete. Today, many of these bridges are slowly approaching the end of their envisaged service life. Current methodology of assessment and evaluation of structural condition is based on visual inspections, which, due to its subjectivity, can lead to delayed interventions, irreparable damages and additional costs. Thus, to support engineers in the process of structural evaluation and prediction of the remaining service life, the Austrian Federal Railways (${\ddot{O}}$ BB) commissioned the formation of a concept for an anticipatory life cycle management of engineering structures. The part concerning concrete bridges consisted of forming a bridge management system (BMS) in a form of a web-based analysis tool, known as the LeCIE_tool. Contrary to most BMSs, where prediction of a condition is based on Markovian models, in the LeCIE_tool, the time-dependent deterioration mechanisms of chloride- and carbonation-induced corrosion are used as the most common deterioration processes in transportation infrastructure. Hence, the main aim of this article is to describe the background of the introduced tool, with a discussion on exposure classes and crucial parameters of chloride ingress and carbonation models. Moreover, the article presents a verification of the generated analysis tool through service life prediction on a dozen of bridges of the Austrian railway network, as well as a case study with a more detailed description and implementation of the concept applied.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.789-792
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• 2008

Recently, the deteriorations of RC bridge decks on express-way are frequently observed. The major cause of deterioration for the RC concrete bridge decks exposed to de-icing chemiclas would be chloride-induced reinforcement corrosion. Therefore, Waterproofing is necessary for improvement of bridge deck durability and comfortable utility. In this study is to investigate the appearance of deterioration and properties of concrete core from the collect in a bridge deck. The results of this study shows that penetration waterproofing agents shows low infiltration depth and low water-repellent. It appears that the damaging of concrete deck is primarily waterproofing system rather than physical property.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.793-798
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• 2002

This paper presents the analytical results on the seismic retrofit of circular bridge columns with poor lap-splice details using FRP jacket. The as-built column suffered brittle failure due to the deterioration of lap-spliced longitudinal reinforcement without developing its flexural capacity or ductility. The retrofitted columns using FRP jacket showed significant improvement in seismic performance due to FRP's confinement effect. FRP's confinement effect is predicted by the classical elasticity solution for the laminated circular tube manufactural with several layers, and induces the flexural failure instead of bondslip failure.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.973-978
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• 2003

This paper describes the experimental study on seismic strengthening effect of circular bridge columns with poor lap-splice details using FRP(Fiber Reinforced Plastic) wrapping, The as-built column suffered brittle failure due to the deterioration of lap-spliced longitudinal reinforcement without developing its flexural capacity or any ductility, The strengthening columns using FRP wrapping showed significant improvement in seismic performance due to FRP's confinement effect.