• Wind and Structures
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• v.17 no.1
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• pp.69-85
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• 2013

With the sustainability movement, vegetated building envelopes are gaining more popularity. This requires special wind effect investigations, both from sustainability and resiliency perspectives. The current paper focuses on wind load estimation on small- and full-scale trees used as part of green roofs and balconies. Small-scale wind load assessment was carried out using a wind tunnel testing in a global-effect study to understand the interference effects from surrounding structures. Full-scale trees were investigated at a large open-jet facility in a local-effect study to account for the wind-tree interaction. The effect of Reynolds number combined with shape change on the overall loads measured at the base of the trees (near the roots) has been investigated by testing at different model-scales and wind speeds. In addition, high-speed tests were conducted to examine the security of the trees in soil and to assess the effectiveness of a proposed structural mitigation system. Results of the current research show that at relatively high wind speeds the load coefficients tend to be reduced, limiting the wind loads on trees. No resonance or vortex shedding was visually observed.

• Wind and Structures
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• v.32 no.3
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• pp.193-204
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• 2021

The estimation of the extreme wind load (effect) under a mean recurrence interval (MRI) is an important task in the wind-resistant design for the structure. It can be predicted by either first-order method or full-order method, depending on the accuracy and complexity requirement. Although the first-order method with the consideration of wind directionality has been proposed, less work has been done on the full-order method, especially with the wind directionality. In this study, the full-order method considering the wind directionality is proposed based on multivariate joint probability distribution. Meanwhile, considering two wind directions, the difference of the corresponding results based on the first-order method and full-order method is analyzed. Finally, based on the measured wind speed data, the discrepancy between these two methods is investigated. Results show that the difference between two approaches is not obvious under larger MRIs while the underestimation caused by the first-order method can be larger than 15% under smaller MRIs. Overall, the first-order method is sufficient to estimate the extreme wind load (effect).

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.235-240
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• 2005

Articulation type container cranes are the boom forms an inverted L shape when raise. The inner boom section is nearly vertical when raise and the outer boom section is nearly horizontal. Articulation type container cranes were developed as a lower height crane to meet aircraft clearance requirements. Because the height of an Articulation type container crane is about 70m, the crane is subjected to the effect of Wind load. Therefore, the problem on the effect of Wind load is receiving carefully study. The researches for the effect of wind load on the structural stability of a conventional container crane are conducted. In this study, we carried out the investigation for an articulation type container crane. When a wind load is applied to a container crane, we analyzed the reaction force distribution at each supporting point of a crane with respect to a wind load direction and the effect of the change of the machinery house location on the structural stability rf a crane by carrying out Finite Element Analysis.

• Wind and Structures
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• v.16 no.3
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• pp.263-278
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• 2013

The fatigue load of a turbine blade has become more important because the size of commercial wind turbines has increased dramatically in the past 30 years. The reduction of the fatigue load can result in an increase in operational efficiency. This paper numerically investigates the load reduction of large wind turbine blades using active aerodynamic load control devices, namely trailing edge flaps. The PD and LQG controllers are used to determine the trailing edge flap angle; the difference between the root bending moment and its mean value during turbulent wind conditions is used as the error signal of the controllers. By numerically analyzing the effect of the trailing edge flaps on the wind turbines, a reduction of 30-50% in the standard deviation of the root bending moment was achieved. This result implies a reduction in the fatigue damage on the wind turbines, which allows the turbine blade lengths to be increased without exceeding the designed fatigue damage limit.

• Wind and Structures
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• v.32 no.5
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• pp.501-508
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• 2021

The turbine industry demands a reliable design with affordable cost. As technological advances begin to support turbines of huge sizes, and the increasing importance of wind turbines from day to day make design safety conditions more important. Wind turbines are exposed to environmental conditions that can affect their installation, durability, and operation. International Electrotechnical Commission (IEC) 61400-1 design load cases consist of analyses involving wind turbine operating conditions. This design load cases (DLC) is important for determining fatigue loads (i.e., forces and moments) that occur as a result of expected conditions throughout the life of the machine. With the help of FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open source software, the NREL 5MW land base wind turbine model was used. IEC 61400-1 wind turbine design standard procedures assessed turbine behavior and fatigue damage to the tower base of dynamic loads in different design conditions. Real characteristic wind speed distribution and multi-directional effect specific to the site were taken into consideration. The effect of these conditions on the economic service life of the turbine has been studied.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.148-155
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• 2005

This study was carried out to analyze the effect of direction of wind load and machinery house location on the stability of container crane loading/unloading a container on a vessel. The overturning moment of container crane under wind load at 50m/s velocity was estimated by analyzing reaction forces at each supporting point. And variations of reaction forces at each supporting point of a container crane were analyzed according to direction of wind load and machinery house location. The critical location of machinery house was also investigated to install a tie-down which has an anti-overturning function of container crane at the land side supporting point.

• Wind and Structures
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• v.21 no.3
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• pp.311-329
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• 2015

A method for analyzing the coupled wind-vehicle-bridge system is proposed that also considers the shielding effect of the bridge tower with triangular wind barriers. The static wind load and the buffeting wind load for both the bridge and the vehicle are included. The shielding effects of the bridge tower and the triangular wind barriers are incorporated by taking the surface integral of the wind load. The inter-history iteration is adopted to solve the vehicle-bridge dynamic equations with time-varying external loads. The results show that after installing the triangular wind barriers in the area of the bridge tower, the bridge response and the vehicle safety factors change slightly. The peak value of the train car body acceleration is significantly reduced when the wind barrier size is increased.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.104-110
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• 2016

The effect of a partially earth anchored cable system on the structural safety of a long span cable-stayed bridge under seismic and wind loads are examined during construction process. By assuming the FCM (free cantilever method) construction stages with structural vulnerability, a multi-mode spectral analysis and a multi-mode buffeting analysis are performed for specific seismic load and wind load, respectively. Results show that the wind load dominates the structural safety of a cable-stayed bridge during construction. And, the application of a partially earth anchored cable system can enhance structural safety under wind load since the maximum pylon moment in the model with partially earth anchored cable system is reduced by 49% under wind load. In contrast, the maximum pylon moment occurred by seismic load is only decreased by 8%.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.228-229
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• 2007

Container cranes are vulnerable structure to difficult weather conditions because there is no shielding facility to protect them from high wind This study carried out to analyze the wind load have an effect on container crane according to a wind direction variation The container crane for this research is a model of a 61-ton class tint used broadly in the current ports. The dimension of an external fluid field set up 500m ${\times}$ 200m. In this study, Mean wind load conformed to the 'Design Criteria of Wind Load' in 'Load Criteria of Building Structures' and an external fluid field divided in interval of 10 degrees to analyze effect according to a wind direction From there, we carried out to the computation fluid dynamic analysis using a CFX-10 Therefore as consequence of computation fluid dynamic analysis and wind velocity experiment make a comparative study, we analyzed a wind load for construction design if container crane.

• Journal of Navigation and Port Research
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• v.32 no.3
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• pp.251-255
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• 2008

Container cranes are vulnerable structure about difficult weather conditions bemuse there is no shielding facility to protect them from the strong wind. This study was carried out to analyze the wind load which have an effect on container crane according to the various wind direction. The container crane is a model of a 61-ton class that used broadly in the current ports. The external fluid field was figured as a cylinder which was set up $500m{\times}200m$. In this study, we applied mean wind load conformed to 'Design Criteria of Wind Load' in 'Load Criteria of Building Structures' and an external fluid field was divided as interval of 10 degrees to analyze effect according to a wind direction In this conditions, we carried out the computation fluid dynamic analysis using the CFX-10. As we compared computation fluid dynamic analysis with wind tunnel test, we analyzed the wind load which was needed to design the container crane.