• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.427-436
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• 2009

In this study, new type of pile foundation was introduced for the better performance of lateral resistance than conventional piles by adopting enlarged upper section, because offshore structure design is subjected to the lateral loading. The numerical simulations were peformed in order to find out the lateral behaviour of the proposed pile. The economical efficiency of new pile system was also analyzed by considering the construction characteristics and material costs as well as the real field condition of harbor sites in Korea. From the study, it was revealed that the lateral resistance of piles with enlarged upper section is increased compared to conventional steel pile, and the construction costs would be reduced to about 62~80% of previous methods.

• Smart Structures and Systems
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• v.20 no.2
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• pp.163-173
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• 2017

Structural health monitoring (SHM) of civil infrastructure using fiber Bragg grating sensor networks (FBGSNs) has received significant public attention in recent years. However, there is currently little research on the health-monitoring technology of high-piled wharfs in coastal ports using the fiber Bragg grating (FBG) sensor technique. The benefits of FBG sensors are their small size, light weight, lack of conductivity, resistance corrosion, multiplexing ability and immunity to electromagnetic interference. Based on the properties of high-piled wharfs in coastal ports and servicing seawater environment and the benefits of FBG sensors, the SHM system for a high-piled wharf in the Tianjin Port of China is devised and deployed partly using the FBG sensor technique. In addition, the health-monitoring parameters are proposed. The system can monitor the structural mechanical properties and durability, which provides a state-of-the-art mean to monitor the health conditions of the wharf and display the monitored data with the BIM technique. In total, 289 FBG stain sensors, 87 FBG temperature sensors, 20 FBG obliquity sensors, 16 FBG pressure sensors, 8 FBG acceleration sensors and 4 anode ladders are installed in the components of the back platform and front platform. After the installation of some components in the wharf construction site, the good signal that each sensor measures demonstrates the suitability of the sensor setup methods, and it is proper for the full-scale, continuous, autonomous SHM deployment for the high-piled wharf in the costal port. The South 27# Wharf SHM system constitutes the largest deployment of FBG sensors for wharf structures in costal ports to date. This deployment demonstrates the strong potential of FBGSNs to monitor the health of large-scale coastal wharf structures. This study can provide a reference to the long-term health-monitoring system deployment for high-piled wharf structures in coastal ports.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.85-96
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• 2011

A breakwater is a important structure for both calmness of harbor and protection of the port facilities from waves generated from typhoons or wind. This study adopted the rubble mound breakwater, which is one of the most popular type of breakwaters in Korea. Rubble mound breakwater had been designed by considering only static condition previously. Recently, a dynamic wave-load due to waves has been also considered in designing breakwater. In design, the wave-load is assumed as an uniform load which only acts in the front slope of the breakwater. However, the assumption is not applicable in reality. In this study, therefore, a real-time wave-load acting on the breakwater instead of the uniform load is considered, and it is assumed to be acting on the seabed too. Based on the numerical analysis, it is found that there is a significant difference in the maximum settlement compared with the result predicted by the existing design method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.209-216
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• 2004

In A bridge which connects Mokpo North Harbor and Com Island is going to be constructed until 2009. For the bridges being built in the navigable water area, it is indispensible to carry out vessel traffic safety assessment from the viewpoint of shiphandlers, however, there exist no specific guidelines for the necessary conditions whim the bridge designers can rely on. In this paper, traffic safety assessment procedures for the layout of the bridge is briefly introduced, and the conditions whim should be taken into account at the initial design stage of the bridge is surveyed. For the safety assessment of the bridge design, ship navigation simulations, such as RTS(real time simulation} and FTS(fast time simulation), are carried out, the results of which are statistically analysed to estimate the probability of collision between the ship and the pier of the bridge.

• Journal of the Korean GEO-environmental Society
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• v.2 no.2
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• pp.41-50
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• 2001

In this study, for the stability analysis of marine embankment, the slope stability analysis and possibility of lateral movement with the marine embankment in ${\bigcirc}{\bigcirc}$harbor were carried out. In order to simulate the practical site condition, the expected maximum sea water level and maximum embankment height were assumed for these analyses. For the evaluation of soil properties, field test, laboratory test, and especially chemical composition analysis were performed for the this analysis. Based on these test results, the soil parameters were determined by applying ground improvement concept under columnar stabilized ground condition and also the effect of staged backfilling was considered under the dredged ground condition. For the optimal design, the stability analyses of embankment with changed height and unchanged height were performed under unimproved soil condition. The result showed that both cases were unstable not only with slope stability but also with lateral movement. Therefore, Deep Mortar Piling was applied for stability analysis and this result was safe. As the conclusion, the deep mortar piling method was suggested as reinforced foundation design for this site.

• Journal of Navigation and Port Research
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• v.28 no.8
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• pp.735-743
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• 2004

A bridge which connects Mokpo North Harbor and Goha Island is going to be constructed until 2009. For the bridges being built in the navigable water area, it is indispensible to carry out vessel traffic safety assessment from the viewpoint of shiphandlers, however, there exist no specific guidelines for the necessary conditions which the bridge designers can rely on. In this paper, traffic safety assessment procedures for the layout of the bridge are briefly introduced, and the conditions which should be taken into account at the initial design stage of the bridge are surveyed For the safety assessment of the bridge design, ship navigation simulations, such as RTS( real time simulation) and FTS(fast time simulation), are carried out, the results of which are statistically analysed to estimate the probability of collision between the ship and the pier of the bridge.

• Journal of Navigation and Port Research
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• v.33 no.9
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• pp.645-651
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• 2009

In this study, a series of laboratory experiments were carried out to investigate the weak reflection of regular and random water waves over a train of protruded permeable shore structures. A cylindrical slit type breakwater and the alternatives are employed and compared for reflecting and transmitting capabilities of incident waves including wave forces. A series of random waves were generated by using the Bretschneider-Mitsuyasu frequency and directional spectrum. Measured spectrum of irregular waves without breakwaters is verified by comparing with those of the input waves generated. Weak reflection is occurred at the breakwater center of the peak frequency. If the row of breakwaters is fixed at three layers and the relative height of breakwater is fixed at 0.6, around 45% of incident wave energy is reflected to offshore. It is also found that the transmission of directional random waves increases as the maximum frequency parameter increases. A very good agreement is observed. Reflection coefficients of permeable submerged breakwaters are less than those of impermeable breakwaters. The upside-down L shape is recommended for a small fishery harbor mooring in terms of reflecting capability and of practical application. The final design was applied to the wharf of a small beach of Seolly, near Namhae at the southeast coast of Korea.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.117-118
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• 2012

As the technical standard of hydrographic data was transferred from S-57 to S-101, a standard system was set up for producing the next generation ENCs but also various maritime safety information. ECDIS that display a S-57 ENC and include a navigation support function, should be developed considering new standard. S-10X data and e-Nav information can be used in this system. In this study, an implementation mechanism of S-100 standard was analyzed for design of navigation support system based on S-100. From the results, it was designed as loading module of S-10X data, display module of SENC, navigation supporting module. Also, this study considered a next generation ENC, a bathymetric grid data, an electronic nautical publication as an input information.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.2
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• pp.173-183
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• 2010

In a split beam echo sounder, the transducer design needs to have minimal side lobes because the angular position and level of the side lobes establishes the usable signal level and phase angle limits for determining target strength. In order to suppress effectively the generation of unwanted side lobes in the directivity pattern of split beam transducer, the spacing and size of the transducer elements need to be controlled less than half of a wavelength. With this purpose, a 50 kHz tonpilz type transducer with a half-wavelength diameter in relation to the development of a split beam transducer was designed using the equivalent circuit model, and the underwater performance characteristics were measured and analyzed. From the in-air and in-water impedance responses, the measured value of the electro-acoustic conversion efficiency for the designed transducer was 51.6%. A maximum transmitting voltage response (TVR) value of 172.25dB re $1{\mu}Pa/V$ at 1m was achieved at 52.92kHz with a specially designed matching network and the quality factor was 10.3 with the transmitting bandwidth of 5.14kHz. A maximum receiving sensitivity (SRT) of -183.57dB re $1V/{\mu}Pa$ was measured at 51.45kHz and the receiving bandwidth at -3dB was 1.71kHz. These results suggest that the designed tonpilz type transducer can be effectively used in the development of a split beam transducer for a 50kHz fish sizing echo sounder.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.519-526
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• 2019

This study proposes a methodology for estimating the appropriate capacity of anchorage for ports requiring the establishment of waiting anchorage and then applying the methodology to the ports in Jinhae Bay to compare it with the anchorage capacity of major ports in Korea. To estimate the appropriate anchorage capacity, the "Anchorage Capacity Index" was used, which was calculated from the "Total Gross Tonnage" and "Simultaneous Anchoring Capacity". The calculations were made according to the anchorage capacity index of 0.89 of the target harbors. The adequate anchorage capacity index for the new waiting anchorage was analyzed at a level of 6.0. If the concept of anchorage capacity index suggested in this study is reflected as a new design criteria of waiting anchorage, it will be helpful for the safety of berth, safety of anchorage and effective operation of harbor.