• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.04a
• /
• pp.827-832
• /
• 2000

Bridge structure is known as one of important infrafacilities for comfortable human life. Recent long-span bridges, such as Kwang-Ahn Grand bridge, Seo-hae Grand Bridge, Young-Jong Grand Bridge, etc, have been designed and constructed near the seaside without in-depth consideration of concrete durability problem. It is in particular noted tat corrosion of reinforcement steel in concrete is very important for the durability enhancement of concrete structures. The objective of this experimental study is to investigate the corrosion behavior of reinforcing steels in concrete specimens which are exposed to cyclic wet and dry saltwaters, and then to develop pertinent corrosion protection system such as rational cover depth, corrosion inhibitors, cathodic system for reinforced bridges exposed to marine environment.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.1
• /
• pp.175-183
• /
• 2022

The collision between a ship and bridge across a waterway may result in extremely serious consequences that may endanger the safety of life and property. Therefore, factors affecting ship bridge collision must be investigated, and the impact force should be discussed based on various collision conditions. In this study, a finite element model of ship bridge collision is established, and the peak impact force of a ship bridge collision based on 50 operating conditions combined with three input parameters, i.e., ship loading condition, ship speed, and ship bridge collision angle, is calculated via numerical simulation. Using neural network models trained with the numerical simulation results, the prediction model of the peak impact force of ship bridge collision involving an extremely short calculation time on the order of milliseconds is established. The neural network models used in this study are the basic backpropagation neural network model and Elman neural network model, which can manage temporal information. The accuracy of the neural network models is verified using 10 test samples based on the operating conditions. Results of a verification test show that the Elman neural network model performs better than the backpropagation neural network model, with a mean relative error of 4.566% and relative errors of less than 5% in 8 among 10 test cases. The trained neural network can yield a reliable ship bridge collision force instantaneously only when the required parameters are specified and a nonlinear finite element solution process is not required. The proposed model can be used to predict whether a catastrophic collision will occur during ship navigation, and thus hence the safety of crew operating the ship.

• Journal of Advanced Marine Engineering and Technology
• /
• v.32 no.2
• /
• pp.276-283
• /
• 2008

The purpose of this study is to measure and analyze the ship's indoor thermal conditions and also to integrate experimental database of those which are supplied and controlled by marine HVAC. On this study, temperature, humidity and air volume of 6 different needs' cabin are measured like previous report on a newly-launched training ship during 25th through 27th of July, 2007. Followings are the results of this study. (1)The air supply volumes to each cabins are measured 250CMH(Recreation room), 800CMH(Conference room), 1.000CMH(Bridge), 5,100CMH(Lecture room) respectively. (2)The temperatures are maintained at $21{\sim}27^{\circ}C$ in almost cabins through measuring period, but the temperatures are fluctuated over ${\pm}4^{\circ}C$ at the bridge and conference room. (3)The relative humidities are shown between $40{\sim}60%$ known as comfort conditions, but the conference room is needed to dehumidified because of over 70% humidity. (4)From the student cabins' measurements which have different supply diffuser(s), it is clear that the design is suitable for this case. (5)Because of temperature diversities, only 32% among the measured data are satisfied with the comfort standard range proposed by ASHREA.

• Advances in Computational Design
• /
• v.4 no.1
• /
• pp.1-13
• /
• 2019

Recent generations of smartphones offer accelerometer sensors as a standard feature. While this has led to the development of a number of related applications (apps), there has been no study on their comparative or individual performance against a benchmark. This paper investigates the comparative performance of a number of smartphone accelerometer apps amongst themselves and to a calibrated benchmark accelerometer. A total of 12 apps were selected for testing out of 90 following an initial review. The selected apps were subjected to sinusoidal vibration testing of varying frequency and the response of each compared against the calibrated baseline accelerometer. The performance of apps was quantified using analysis of variance (ANOVA) and test of significance was carried out. The apps were then compared for a realistic dynamic scenario of measuring the acceleration response of a bridge due to the passage of a French Train $\grave{a}$ Grande Vitesse (TGV) in a laboratory environment.

• Proceedings of KOSOMES biannual meeting
• /
• 2017.04a
• /
• pp.7-7
• /
• 2017

• Journal of the Korea Society for Simulation
• /
• v.11 no.4
• /
• pp.81-89
• /
• 2002

Several full mission simulators have been installed since about 10 years ago in Korea. The newly established Marine Simulation Training and Research Center at Korea Maritime University has played a key role for education and training of both cadets and in-service officers trainees, and for research on Korea ports such as Jeju international cruise port, Ulsan SBM and Kwangyang container port and many others. This study mainly focuses maritime education and training on the ship handling simulation and the bridge resource management conducted by Korea Maritime University.

• Journal of Navigation and Port Research
• /
• v.33 no.5
• /
• pp.295-301
• /
• 2009

Recently, considerable number of bridges crossing over navigable waterways are under construction for the connection of coastal islands with mainland and the optimization of logistic system However, the most planned bridges have been initiated without paying much attention to ships safety aspects but with great emphasis on the economic factors, it has often been confronted with difficult social issues arising from opposing views and conflicts between building bodies and affected port users. The main reason for the conflicts is the lack of standards or specifications on the bridge design The proper location and scale of sea bridges are suggested in this paper considering fairway design criteria of both domestic and foreign countries, status analysis on the designs of existing and planned bridges, investigation findings of bridge-related marine accidents, the views of pilots and navigators collected through questionnaire. Since there is no general domestic or international design rules on bridge's scale, the design standards proposed in this paper may be useful at initial design stage of bridge.

• Journal of Marine Life Science
• /
• v.6 no.2
• /
• pp.106-116
• /
• 2021

To secure basic data by monitoring the growth of salmon (Oncorhynchus keta) released to the Taehwa River. After discharge, the characteristics of the young salmon distribution and migration rate habitat were investigated for two years. A total of 4 points [Sunbawi bridge (St.1), Guyeong bridge (St.2), Samho bridge (St.3), and Myeongchon bridge (St.4)] were investigated. The survey of 2017 indicating an increase of 10 mm in average length and 0.8 g in average weight, and the survey of 2018 indicating an increase of 10 mm in average length and 0.5 g in average weight. Among 39 species, 10 insectivorous and 12 omnivorous, are believed to compete with young salmon for food. 6, 5, 6 and 8 predatory fish species has emerged at each site, respectively. According to this study, it is believed that St.1 and St.2 points are more proper as discharge location of young salmon because these two points have less varied in depth, flow rate, salt concentration etc. In addition, it is thought that the night or dawn time in early January is the best discharge time of young salmon fish because predatory fish such as Korean piscivorous chub and bass etc. does not eat food actively at that time.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.20 no.2
• /
• pp.203-211
• /
• 2008

More recently, the massive marine bridges in a ship passage have been constructed on the sea. Therefore, the ship impact protection for the bridge-piers are installed to consider the possibility of vessel collision danger. Due to the ship impact protection, the pier-scour characteristics are changed in comparison with the condition without the ship impact protection (SIP). In this study, the physical modeling for the Incheon Sea-Crossing Bridge was performed to analyze the pier-scour characteristics with respect to the vessel collision protection. The rigid and movable bed tests were conducted to evaluate the flow pattern, scour depth, and scourhole with and without the ship impact protection. The experimental results for the maximum scour depth is increased 0.24 m in W1 pier at the same location and 2.4 m in W2+3+4 piers due to the SIP installation. Especially, the maximum scour depth in W2+3+4 piers was occurred around the SIP.

• Journal of Navigation and Port Research
• /
• v.29 no.1 s.97
• /
• pp.65-69
• /
• 2005

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, has been proposed by the private capital in 1999. But the optimal width of the main span has 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, one-way or two-way of vessels over 10,000G/T, in the 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.