• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.103-110
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• 2006

The rail clamp is very important device to prevent that a container crane slips along a rail due to the wind blast as well as to locate the crane in the set position during an operating mode. Recently, the design wind speed criteria were intensified from the wind speed of 16m/s to 35m/s during an operating mode, and from 50m/s to 75m/s during a stowed mode in Korea, according to the 'Inspection Criteria for Facilities and Equipments in Port' reformed after typhoon 'Maemi'. In order to design the wedge type rail clamp for the reinforced design wind speed criteria of 35m/s, we carried out the finite element analysis of the rail clamp with respect to the wedge angle, and analyzed the relationship between the wedge angle and the sliding distance of the rail clamp.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1626-1629
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• 2005

Recently many countries have concentrated their effort on the port automation, in order to be the Hub-port, that the Ultra Large Container Ship could come alongside the Quay, in their region. As the magnitude of the container ship increase, that of the Quay crane increases from 50ton-class to 61ton-class more and more. The wind speed criteria to design the structures used in the port was upgraded from 20m/s to 40m/s due to change of the weather condition. Our laboratory could have the ability to design the wedge type rail clamp for 50ton-class Quay crane in 30m/s wind speed. Accordingly we analyzed the load condition of the Quay crane about 40m/s wind speed upgraded from 20m/s and designed the wedge type rail clamp for 50ton and 61ton-class Quay crane.

• Wind and Structures
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• v.26 no.6
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• pp.383-395
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• 2018

An accurate determination of wind speed distribution is the basis for an evaluation of the wind energy potential required to design a wind turbine, so it is important to estimate unknown parameters of wind speed distribution. In this paper, Gumbel distribution is used in modelling wind speed data, and alternative robust estimation methods to estimate its parameters are considered. The methodologies used to obtain the estimators of the parameters are least absolute deviation, weighted least absolute deviation, median/MAD and least median of squares. The performances of the estimators are compared with traditional estimation methods (i.e., maximum likelihood and least squares) according to bias, mean square deviation and total mean square deviation criteria using a Monte-Carlo simulation study for the data with and without outliers. The simulation results show that least median of squares and median/MAD estimators are more efficient than others for data with outliers in many cases. However, median/MAD estimator is not consistent for location parameter of Gumbel distribution in all cases. In real data application, it is firstly demonstrated that Gumbel distribution fits the daily mean wind speed data well and is also better one to model the data than Weibull distribution with respect to the root mean square error and coefficient of determination criteria. Next, the wind data modified by outliers is analysed to show the performance of the proposed estimators by using numerical and graphical methods.

• Wind and Structures
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• v.14 no.1
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• pp.71-80
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• 2011

This study presents a decision making process for installation of wind barrier which is used to reduce the wind speed applied to running vehicles on expressway. To determine whether it is needed to install wind barrier or not, cost and benefit from wind barrier are calculated during lifetime. In obtaining car accidental risk, probabilistic distribution of wind speed, daily traffic volume, mixture ratio in the volume, and duration time for wind speed range are considered. It is recommended to install wind barrier if benefit from the barrier installation exceed construction cost. In the numerical examples, case studies were shown for risk and benefit calculation and main risky regions on Korean highway were all evaluated to identify the number of installation sites.

• Journal of Navigation and Port Research
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• v.29 no.7
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• pp.641-646
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• 2005

In cargo-working, it unavoidably happens that the quay crane slip along the rail and the container move from side to side. Especially, they involve a lot of risk in bad weather. The rail clamp is a mooring device to prevent that the quay crane slips along the rail due to bad weather or the wind blast while the quay crane do the cargo-working And it will play a greater role in port container terminal integration and automation To design the wedge type rail clamp, it is very important to determine the wedge angle. In this study, we expect that the design wind speed of the quay crane will change over 16m/s. Assuming that the design wind speed is 40m/s, we determined the proper wedge angle of the wedge type rail clamp for the 50ton class quay crane.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.273-280
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• 2001

In this study, a comparison between the structural design criteria for a catenary system with the maximum design speed of 100km/h and that of 300km/h was performed in order to establish that of 200km/h. According to the result, catenary design criteria for 300km/h operation is more conservative than that for 100km/h operation. This result shows that higher wind pressure and safety factor are adopted to catenary design for 300km/h operation. So, for the purpose of the economic structural design for catenary system, it is necessary to review the adoption possibility of catenary system for 100km/h operation first. In order to review the adoption possibility for catenary system for 100km/h operation, design criteria for 300km/h operation should be chosen for safer catenary structure.

• Wind and Structures
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• v.14 no.1
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• pp.55-70
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• 2011

This study investigates the design criteria required for wind barriers to protect vehicles running on an expressway under a high side wind. At the first stage of this study, the lateral deviations of vehicles in crosswinds were computed from the commercial software, CarSim and TruckSim, and the critical wind speeds for a car accident were then evaluated from a predefined car accident index. The critical wind speeds for driving stability were found to be 35 m/s for a small passenger car, yet 30 m/s for a truck and a bus. From the wind tunnel tests, the minimum height of a wind barrier required to reduce the wind speed by 50% was found to be 12.5% of the road width. In the case of parallel bridges, the placement of two edge wind barriers plus one wind barrier at center was recommended for a separation distance larger than 20 m (four lanes) and 10 m (six lanes) respectively, otherwise two wind barriers were recommended.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1043-1053
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• 1994

This study suggests a practical but rational approach for the development of reliability-based LRFD criteria for transmission towers under wind and ice loadings in Korea. Based on available statistical data on wind speed and icing on transmission lines in Korea, the design wind and ice loads are obtained by Monte Carlo Simulations. In the study, the AFOSM reliability method and an Importance Sampling Technique are used for the element and system reliability evaluation of actual transmission towers. Based on the selected target reliabilities, a set of load and resistance factors for the LRFD criteria are calibrated using the AFOSM and the code optimization technique.

• Wind and Structures
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• v.37 no.4
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• pp.315-329
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• 2023

We investigated the wind characteristics in the near-surface layer during the landfall of Typhoon Mujigae (2015) based on observations from wind towers in the coastal areas of Guandong province. Typhoon Mujigae made landfall in this region from 01:00 UTC to 10:00 UTC on October 4, 2015. In the region influenced by the eyewall of the tropical cyclone, the horizontal wind speed was characterized by a double peak, the wind direction changed by >180°, the vertical wind speed increased by three to four times, and the angle of attack increased significantly to a maximum of 7°, exceeding the recommended values in current design criteria. The vertical wind profile may not conform to a power law distribution in the near-surface layer in the region impacted by the eyewall and spiral rainband. The gust factors were relatively dispersed when the horizontal wind speed was small and tended to a smaller value and became more stable with an increase in the horizontal wind speed. The variation in the gust factors was the combined result of the height, wind direction, and circulation systems of the tropical cyclone. The turbulence intensity and the downwind turbulence energy spectrum both increased notably in the eyewall and spiral rainband and no longer satisfied the assumption of isotropy in the inertial subrange and the -5/3 law. This result was more significant in the eyewall area than in the spiral rainband. These results provide a reference for forecasting tropical cyclones, wind-resistant design, and hazard prevention in coastal areas of China to reduce the damage caused by high winds induced by tropical cyclones.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.115-120
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• 2006

The rail clamp is the device to prevent the crane slips along rails from the wind blast as well as to locate a container crane in the set position in operating mode. In this study we conduct the research for the sliding distance of rail clamp and the proper position of supporter with respect to the wedge angle in the wedge type rail clamp. The sliding distance to display the clamping force of the jaw pad corresponding to the design wind speed criteria is determined by the total displacement of the rail clamp at the roller center and the wedge angle. And the supporter is the device to prevent the overload which is applied on each part of the rail clamp by wind speed increment, because a clamping force is generated by the sliding of the wedge due to the wind. Accordingly the position of the supporter to prevent the overload is determined by analyzing the forces applied to the rail clamp. In order to analyze the sliding distance and the proper position of supporter with respect to the wedge angle as the wind speed is 40m/s, 5-kinds of wedge angles, such as 2, 4, 6, 8, $10^{\circ}$, were adopted as the design parameter.