• Journal of Ocean Engineering and Technology
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• v.18 no.1
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• pp.47-52
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• 2004

Greater holding force of an anchor is required for maintaining the position of a larger floating structure. According to the series of model tests of pile anchors with movable fluke, the square type pile anchor, with fluke, showed more than 6 times of the uplift pulling force, compared to the same type pile anchor, without fluke. This uplift force is 100 times its weight. When the water depth is more than 40m, It is difficult to install the pile anchor. For a convenient installation method, a type of manipulator is proposed for the separation of a weight and buoyancy controller, using TRIZ.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.394-399
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• 2005

Embedded rail track can be described as a track structure that is completely covered within pavement. Rail supported continually on a concrete slab or concrete plinth. There are many kinds of types such as non-resilient track and resilient track, super resilient embedded track (floating slab). Embedded rail track is generally the standard for light rail transit routes because this track has many advantages such as reducing noise, maintenance cost and weight of track. In this paper, decision of track profile is restricted by the optimum levels of the flangeway and the gap between the rail head and the pavement surface of depressing tread zone. By result of this study, embedded rail track can reduce corrosion of rail, internal stress and rail deflection.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1057-1063
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• 2023

The urban railway sleeper floating track, the subject of this study, is an anti-vibration track to reduce vibration transmitted to the structure. currently, the replacement cycle of resilience pad for sleeper floating tracks is set and operated based on load. however, most previous studies were conducted on load-based structural safety aspects, such as fatigue life evaluation of sleeper anti-vibration pads and increase in track impact coefficient and track support stiffness due to increase in spring stiffness. therefore, in this study, we measure the vibration acceleration of the ballast for each analysis section and use the results of 7 million fatigue tests to calculate the spring stiffness of the resilience pad for each section. the spring stiffness of the resilience pad calculated for each section was set as the analysis data and the concrete vibration acceleration was derived analytically. the adequacy of analysis modeling was verified as the analyzed concrete bed vibration acceleration for each section was within the field-measured concrete bed vibration acceleration range. using the vibration acceleration curve according to the derived spring stiffness change, the spring stiffness of the resilience pad is estimated from the measured vibration acceleration. therefore, we would like to present a technique that can estimate the spring stiffness of resilience pad of a running track using the vibration acceleration of the measured concrete bed.

• Computers and Concrete
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• v.31 no.5
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• pp.405-417
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• 2023

The submerged floating tunnel (SFT) is tethered by mooring lines anchored to the seabed, therefore, the structural integrity of the anchor should be sensitively managed. Despite their importance, reaction forces cannot be simply measured by attaching sensors or load cells because of the structural and environmental characteristics of the submerged structure. Therefore, we propose an effective method for estimating the reaction forces at the seabed anchor of a submerged floating tunnel using a structural pattern model. First, a structural pattern model is established to use the correlation between tunnel motion and anchor reactions via a deep learning algorithm. Once the pattern model is established, it is directly used to estimate the reaction forces by inputting the tunnel motion data, which can be directly measured inside the tunnel. Because the sequential characteristics of responses in the time domain should be considered, the long short-term memory (LSTM) algorithm is mainly used to recognize structural behavioral patterns. Using hydrodynamics-based simulations, big data on the structural behavior of the SFT under various waves were generated, and the prepared datasets were used to validate the proposed method. The simulation-based validation results clearly show that the proposed method can precisely estimate time-series reactions using only acceleration data. In addition to real-time structural health monitoring, the proposed method can be useful for forensics when an unexpected accident or failure is related to the seabed anchors of the SFT.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.177-180
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• 2008

Recently, the research of FRP bar as an alternative reinforcing material in reinforced concrete structures has increased to get an innovative solution to the corrosion problem. In addition to the noncorrosive nature of FRP materials, they also have a high strength-to-weight ratio. Therefore, when light weight concrete reinforced with FRP bar is used in marine environment, for instance floating structures, some advantages can be expected. But researches for the light weight concrete structure using FRP bar as a flexural reinforcement are limited to date. In this paper, the concrete shear contribution of the light weight concrete beam reinforced with GFRP bar was studied. Experiment for beams varying concrete compressive strengths and flexural reinforcement ratios was conducted and analysed. The test results showed that 75% of values obtained from proposed equation in preceding research were well agreed with the test results and were better results than the one predicted by the ACI 440.1R-06 code.

• KIEAE Journal
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• v.4 no.3
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• pp.71-78
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• 2004

Apartment housing is a widely-spread type in Korean housing market. Nevertheless, it has caused serious problems such as traditional community corruption, unsafe structure, defects and litigation from noise. Noise, especially in concrete structure for apartment housing, is hardly controlled in proper to prevent sound transmission between upper and lower families with existing system. In foreign countries, there are floating floor system to enhance the noise control performance in multi-family housing. This study is to examine the impact sound insulation performance of floors according to the different P'yong and Layers by field measurement in highrise building.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.5-8
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• 2008

Apartment housing is a widely-spread type in Korean housing market. Nevertheless, it has caused serious problems such as traditional community corruption, unsafe structure, defects and litigation from noise. Noise, especially in concrete structure for apartment housing, is hardly controlled in proper to prevent sound transmission between upper and lower families with existing system, In foreign countries, there are floating floor systems to enhance the noise control performance in multi-family housing. Therefore, this study aims to analyze subjective responses on sound characteristics in residential buildings. We analyzed the residential response and the quantities of measured data from environmental noise. The results of this study will be useful to provide guideline to make policy of environmental noise and criteria.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.248-255
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• 2011

Impact factor of concrete and ballast track which has been used in Korea railway was applied to equation (1+0.513V/100) from AREA. As the use of this equation, overcapacity of track design might be occurred. Therefore, this study compared impact of ballast track (well, bad) and concrete track (sleeper embeded system, rail floating and sleeper floating) by field test to analyzing dynamic effect of track structure's characterstic and wheel load on service line. In addition, it suggested a method to generate reasonable impact factor on each track type.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.105-114
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• 2006

Together with the trend of enhancement in domestic industrial development and economic progress due to import and export, the demand for construction of the roads, bridges, especially port facilities, and several coastal protection and ocean structures is increasing rapidly. MOMAF of Korean Government is driving construction of 9 new ports and renovation of the existing fishery ports. Among these structures most of bridge base, wharves, dolphins, quays, and jetties are being newly built of steel or concrete pile. As the base, supporting bulkheads, and piles are underwater after construction, it is difficult to figure out the status of structures and not enough to get maintenance and strengthen the structures. Every year, moreover, these works suck the government budget due to higher incomplete maintenance expense for protection from corrosions of structures and increased underwater construction period. for the purpose of cutting down the government budget, it is necessary to extend the life cycle of the existing structures. We developed a new method for maintenance of submerged structures near the waterline by allowing dry work environment with the floating caisson. The method shows easy to move around the working area and handle. It also showed not only a significant reduction of maintenance expenses and time for anti-corrosion work but also better protection. This will be a milestone to reduce the maintenance and construction expenses for the shore and water structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1A
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• pp.19-30
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• 2012

Recently, vision-based dynamic deflection measurement techniques have significant interests and are getting more popular owing to development of the high-quality and low-price camcorder and also image processing algorithm. However, there are still several research issues to be improved including the self-vibration of vision device, i.e. camcorder, and the image processing algorithm in device aspect, and also the application area should be extended to measure three dimensional movement of floating structures in application aspect. In this study, vision-based dynamic motion measurement technique using multiple targets is proposed to measure three dimensional dynamic motion of floating structures. And also a new scheme to select threshold value to discriminate the background from the raw image containing targets. The proposed method is applied to measure the dynamic motion of large concrete floating quay in open sea area under several wave conditions, and the results are compared with the measurement results from conventional RTK-GPS(Real Time Kinematics-Global Positioning System) and MRU(Motion Reference Unit).