• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.133-139
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• 2018

Keeping a proper straight route length under the marine bridge is one of the important factors for the safe passage of ships. However, according to port and harbor design standards, there is only a constant guideline of 8 times the length of the marine bridge underpass. On this study, we used the ES model to determine the ratio of risk to the route width, traffic volume, the degree of curvature of the route, and the length of the straight route in order to derive the optimal straight route distance. As a result, the risk ratio decreased by 2.27% as the route distance increased from 3L to 10L when the degree of curvature of the route was $45^{\circ}$. The risk associated with curvature was found to be 4.83% when the bending degree was changed from $0^{\circ}$ to $45^{\circ}$ in the case of 3L length. In addition, it was confirmed that the risk ratio according to the degree of curvature of the route and the straight route was reduced by 1.45% at maximum under the condition that the width of the line was 400m and the number of the vessels generated per hour was 20. It was verified that a straight route distance more than a certain length is needed depending on the congestion degree and the degree of curvature of the route when constructing the marine bridge.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.786-789
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• 2004

Corrosion of reinforced concrete structures in marine environment is one of the most important mechanism of deterioration. However, conventional rehabilitation techniques in tidal zone, which consist of removing delaminated areas of concrete, cleaning affected steel and patching with portland cements mortar, have proven to be ineffective for marine structures. Also, repairs are often repeated every several years. The purpose of this report is to announce appropriate repair method of highway bridge damaged by chloride attack in marine environment (application of cathodic protection) using FRP and antiwashout underwater mortar.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.4
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• pp.423-429
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• 2017

As invigoration plan of the marine tourism, Busan City has the plan to operate the cruise ship inside of the harbor, but the area has narrow water way with heavy traffic. As a result it is requested to evaluate the safety for the preparation of actual navigation. In this study, the Ship Handling Simulation (SHS) Assessment was conducted, which is regulated by the Maritime Traffic Safety Audit Scheme (MTSAS) in compliance with the Marine Safety Law and the Maritime Traffic Risk Assessment System based on the Electronic Chart Display and Information System (ECDIS). The proximity assessment, control assessment and subjective assessment were implemented, which is enacted by the Marine Safety Law by using the SHS. In the case of proximity assessment, the probability of trespass was not analyzed. As the control assessment, the swept path was measured at 11.7 m and 11.5 m for port entry and port departure respectively, which exceeded the width of the model vessel, 10.4 m over; it was considered as a marginal factor. As a result of the subjective evaluation of the navigator, there would be no difficulty on ship maneuvering by paying particular attention to the mooring vessel nearby the Busan Bridge and Yeongdo Bridge as well as the coming vessel from the invisible sea area when the vessel is entering and departing the port. The Marine Traffic Risk Assessment System analyzed as [Cautious] level until the vessel passed the Busan bridge and the curved area at 5 kts and it became to [Dangerous] level from where it left 75 m to the Busan Bridge. When the vessel passed the Busan Bridge and the curved area at 10 kts and entered the narrow area, it indicated the [Dangerous] level and became to [Very dangerous] level from where it left 410 m to the Busan bridge. In conclusion, the vessel should maintain at the speed of 5 kts to reduce the risk when it passes this area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.179-185
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• 2011

A marine collision accident occurred at the Jin-do water way. A barge loaded with heavy equipment of Power Generation Plant was being towed at its side by two tugs "A" and "B" from Byeg-pa harbour to the designated position to be used for power generation plant near Jin-do bridge. The Power Generation Plant was 40-meters high loaded atop the barge. When the "tugs and tow" were approaching the Jin-do the bridge, the two towing tugs lost maneuvering control of the barge and it went off-course, hit first the waterway embankment and finally struck the lower part of bridge's span and post musing the barge to capsize and sunk its cargo into the sea. The bridge also suffered damages where the top of the Plant struck At the time of the accident, there was a strong tidal current at the waterway. This paper calculates the safe towing force of barges with heavy loads when traversing in a strong tidal current situation in narrow waterway.

• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.101-108
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• 2007

Tugboat has carried out the important role and service in the maritime industry construction, such as port and sea bridge construction, fairway dredging and sea reclamation etc. Furthermore, tugboat takes the largest portion in number of vessel at the domestic registry and barges as big as the general merchant vessel, which are getting specialized and larger, are in operation. In spite of the increase of marine accident under this situation, there has been no proper measure for the safe navigation of tugboat in the aspect of a nation. This paper aims to propose the measure for the safe navigation of tugboat according to the frequent marine accident of tugboat with sea bridge. Therefore, we show a example of the sailing schedule and operation checklist based on the analysis of statistics and precedent of marine accident and the investigation of the actual operation state of tugboat in the aspect of a contract of carriage and a personnel setup, which should be checked by the operator of tugboat, pass through sea bridge safely and propose the safe traffic supporting system based on electronic chart system to improve the safe navigation of tugboat.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.337-342
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• 2004

A construction project of Incheon 2nd bridge, which is connected between the Incheon Song-Do New Town and the Incheon International Airport in Young-Jong-Do, have been proposed by the private capital in 1999. But the optimal span width in the bridge main span have not been decided in spite of the three investigations into the feasibility of ship's safe transit in this planned bridge. In this paper, we study the economic analysis on port operational efficiency according to traffic schemes, me-way or two-way of vessels over 10,000G/T, in the bridge main span of this bridge. In this comparative result, total queueing time due to the one-way in the bridge main span is evaluated 20,362 hours in 2011 and 24,544 hours in 2020. Therefore the demurrage cost and the accumulation cost of freight are evaluated 19.7 billion won in 2011, and 23.3 billion won in 2020, then total accumulated costs during 33 years from 2008 until 2040 are evaluated about 768..9 billion won.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1158-1168
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• 2022

In this study, the specialized marine industry in the area (Incheon) of the case study was identified and the issues related to the current status of marine space utilization were diagnosed. Marine space utilization was selected as the specialized marine industry activity in Incheon through the location quotient index analysis of the marine industry in the target area. A case review of the Yeongheungdo demonstration area and diagnosis of issues in the marine energy development sector with the lowest degree of specialization was conducted, to solve field problems such as overlapping problems in marine-use zones and civil complaints between stakeholders. It was concluded that it is necessary to prepare a policy decision support system based on objective and quantitative grounds.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.545-553
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• 2009

A lot of long-span marine bridge, which connects land to island or island to island, are being designed and constructed lately in south-west coast in South Korea. In the past, caisson foundations in marine were mainly adopted in construction and stability aspect, however, nowadays with development of pile construction technology, drilled shaft foundations are mainly adopted. As the long span cable stayed bridge and suspension bridge applied with lots of loads are being designed, the scale of pile foundations are getting larger. As the construction cost of substructure including foundation in marine bridges is too high, the appropriate evaluation of the axial bearing capacity of pile becomes a core factor to decide the construction cost of foundation if the drilled shaft is adopted as foundation type of bridge. The evaluation values of skin friction and end bearing capacity of drilled shaft in weathered rock suggested in south Korea are only to introduce the foreign specifications, and most of them are designed in a kind of hard soil layer. Also the allowable load of pile section is less than the expected bearing capacity of pile in the soil condition since the allowable capacity of pile is undervalued. Recently in order to improve this factor the bi-axial hydraulic load test of pile was taken, the data of load transfer analysis of pile, unit of skin friction and end bearing capacity are accumulated. In our country, the design of piles are made with ASD, however, LRFD considering service, strength and extreme state was adopted in Incheon Grand Bridge implemented with BTL, and the research to systematize the resistance coefficient appropriate at home country are being progressed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.13-15
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• 2011

This report represents analysis of the maritime casualty in terms of Bridge Resource Management. We evaluate the attitudes and knowledge of bridge officer regarding human factors issues that have been identified as causal to mishaps in high-risk situations. So to reduce human errors our goal is to establish effective officer resource management (ORM) program which is based on all subjects for cadets in IMO model course. In harmonization with STCW(The International Convention on Standards of training, Certification and Watch-keeping for Seafarers), as the result, the curriculumss in the maritime education institutions is surveyed to improve our education system and then reduce the human errors by mariners at sea.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.4
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• pp.79-91
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• 1995

Recently, the AC motor which has a simple structure and needs less maintenance has become to be used frequently as a servomotor for position control in the automatic control field. This paper concerns with a method to improve the current and power waveforms of an AC motor, and the current waveforms and 3$\phi$ power waveforms are analyzed by FFT under verious running conditions. The system is composed of a digital bridge inverter, low pass LC filter, and 3$\phi$ AC motor. Through the computer simulations and experiments, it is confirmed that current waveforms and $\phi$ power waveforms con by improved by utilizing the high order low pass LC filter than that of lower order.