• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.185.2-185.2
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• 2010

With the development of wind industry, the rated power of wind turbine also increase gradually. Accordingly, the size of wind turbine tower becomes larger and larger. The tower base diameter of 2MW wind turbine is about 4m. Larger tower is expected for 4MW or 5MW turbine. Due to limitation of transportation, new type of tower with smooth transportation and effective cost is needed. In this work, a hybrid tower consisting of steel and concrete is designed and analyzed. The optimum ratio of steel and concrete of hybrid tower are calculated as well as the thickness of the concrete part. Different FE analysis including modal analysis, buckling analysis and fatigue analysis are performed to check the design of hybrid tower comparing with the steel tower. Redesign is also expected after various analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1296-1301
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• 2006

The Object of this paper which study for natural frequency of Offshore Wind Turbine Tower with Composite Material and Steel. The Composit Material Tower consist of shell type and stiffened shell type which is made by the method of Filament Winding. And the component of Composite material is used by the Roving RS220PE-535. The Steel Material Tower consist of shell type and stiffened shell type which is made of Mild steel. The Type of Stiffener is hats. This paper compare the Composit Material Offshore Wind Turbine Tower with the Steel Material Offshore wind Turbine Tower and study for Natural Frequency and Mode Shapes.

• Wind and Structures
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• v.35 no.2
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• pp.93-108
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• 2022

Steel tubular towers are commonly used in UHV and long crossing transmission lines. By considering effects of the model scale, the solidity ratio and the ratio of the mean width to the mean height, wind tunnel tests under different wind speeds on twenty tubular steel tower body models and twenty-six tubular steel cross-arm models were completed. Drag coefficients and shielding factors of the experimental tower body models and cross-arm models in wind directional axis for typical skewed angles were obtained. The influence of the lift forces on the skewed wind load factors of tubular steel tower bodies was evaluated. The skewed wind load factors, the wind load distribution factors in transversal and longitudinal direction were calculated for the tubular tower body models and cross-arm models, respectively. Fitting expressions for the skewed wind load factors of tubular steel bodies and cross-arms were determined through nonlinear fitting analysis. Parameters for skewed wind loads determined by wind tunnel tests were compared with the regulations in applicable standards. Suggestions on the drag coefficients, the skewed wind load factors and the wind load distribution factors were proposed for tubular steel transmission towers.

• Wind and Structures
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• v.9 no.5
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• pp.345-356
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• 2006

It is well known that cylinder steel stacks are heavily impacted by vortex-induced vibration. However, the wind-induced vibration behaviors of tower-supported steel stacks are not clarified due to a lack of observation. We studied a stack's response to strong winds over a long period of time by observing the extreme wind-induced vibration of a 200 m-high tower-supported steel stack. This experiment aimed to identify the wind-induced vibration properties of a tower-supported steel stack and assess the validity of the vibration control method used in the experiment. Results revealed a trend in wind-induced vibration behavior. In turn, an effective measure for controlling such vibration was defined by means of increasing the structural damping ratio due to the effects of the tuned mass damper to dramatically decrease the vortex-induced vibration of the stack.

• New & Renewable Energy
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• v.6 no.4
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• pp.50-60
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• 2010

With the development of wind industry, rated power of the wind turbine also increases gradually. Accordingly, size of the wind turbine tower is becoming larger. Tower base diameter of the 2MW wind turbine is about 4m. Larger tower is expected for 4MW or 5MW turbines. Due to limitation of transportation, new type of tower with smooth transportation and effective cost is needed. In this work, a hybrid tower consisting of steel and concrete is designed and analyzed. The optimum ratio of steel and concrete of the hybrid tower is calculated as well as the thickness of the concrete part. Different FE analysis including modal analysis, buckling analysis and static analysis are performed to check the design of hybrid tower comparing with the steel tower. Redesign is also expected after various analyses.

• Steel and Composite Structures
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• v.32 no.2
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• pp.189-198
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• 2019

This paper aims to study the mechanical performance of three-tower four-span suspension bridges with steel truss girders, including the static and dynamic characteristics of the bridge system, and more importantly, the influence of structural parameters including the side-main span ratio, sag-to-span ratio and the girder stiffness on key mechanical indices. For this purpose, the Oujiang River North Estuary Bridge which is a three-tower four-span suspension bridge with two main spans of 800m under construction in China is taken as an example in this study. This will be the first three-tower suspension bridge with steel truss girders in the world. The mechanical performance study and parametric analysis are conducted based on a validated three-dimensional spatial truss finite element model established for the Oujiang River North Estuary Bridge using MIDAS Civil. It is found that a relatively small side-main span ratio seems to be quite appropriate from the perspective of mechanical performance. And decreasing the sag-to-span ratio is an effective way to reduce the horizontal force subjected to the midtower and improve the antiskid safety of the main cable, while the vertical stiffness of the bridge will be reduced. However, the girder stiffness is shown to be of minimal significance on the mechanical performance. The findings from this paper can be used for design of three-tower suspension bridges with steel truss girders.

• Earthquakes and Structures
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• v.7 no.4
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• pp.571-586
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• 2014

This paper presents experimental and numerical study on seismic performance of a super tall steel tower structure. The steel tower, with a height of 388 meters, employs a steel space truss with spiral steel columns to serve as its main lateral load resisting system. Moreover, this space truss was surrounded by the spiral steel columns to form a steel mega system in order to support a 12-story platform building which is located from the height of 230 meters to 263 meters. A 1/40 scaled model for this tower structure was made and tested on shake table under a series of one- and two-dimensional earthquake excitations with gradually increasing acceleration amplitudes. The test model performed elastically up to the seismic excitations representing the earthquakes with a return period of 475 years, and the test model also survived with limited damages under the seismic excitations representing the earthquakes with a return period 2475 years. A finite element model for the prototype structure was further developed and verified. It was noted that the model predictions on dynamic properties and displacement responses agreed reasonably well with test results. The maximum inter-story drift of the tower structure was obtained, and the stress in the steel members was investigated. Results indicated that larger displacement responses were observed for the section from the height of 50 meters to 100 meters in the tower structure. For structural design, applicable measures should be adopted to increase the stiffness and ductility for this section in order to avoid excessive deformations, and to improve the serviceability of the prototype structure.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.289-294
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• 2002

Unlike Tubular Steel Tower, This Composite Material Tower is a low-technology Component, whose design is easy to optimize, and which therefore during the design process-lends itself easily as an object for possible cost reduction at very little effort. This may come in useful as the cost of a tower usually significant part of the total cost of a structure. This paper is written by the Composite Materials Tower which loaded Complex loading in Off and On shore. This Composite Material Tower is made by the Method of Filament Winding, and the Component of Composite Material is used by the Roving RS220PE-535. When it loaded Complex trading, there is a results which is bigger than steel tower deflection. We controlled this 1a18e deflection by stiffeners which has thickness 20mm. At last, Off and On Shore Tower which used Composite Materials is compared with Off and On Shore Tower which used Steel.

• Earthquakes and Structures
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• v.5 no.6
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• pp.657-678
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• 2013

For economical earthquake resistant design of cable-stayed bridge tower, the use of energy dissipation systems for the earthquake protection of steel structures represents an alternative seismic design method where the tower structure could be constructed to dissipate a large amount of earthquake input energy through inelastic deformations in certain positions, which could be easily retrofitted after damage. The design of energy dissipation systems for bridges could be achieved as the result of two conflicting requirements: no damage under serviceability limit state load condition and maximum dissipation under ultimate limit state load condition. A new concept for cable-stayed bridge tower seismic design that incorporates sacrificial link scheme of low yield point steel horizontal beam is introduced to enable the tower frame structure to remain elastic under large seismic excitation. A nonlinear dynamic analysis for the tower model with the proposed energy dissipation systems is carried out and compared to the response obtained for the tower with its original configuration. The improvement in seismic performance of the tower with supplemental passive energy dissipation system has been measured in terms of the reduction achieved in different response quantities. Obtained results show that the proposed energy dissipation system of low yield point steel seismic link could strongly enhance the seismic performance of the tower structure where the tower and the overall bridge demands are significantly reduced. Low yield point steel seismic link effectively reduces the damage of main structural members under earthquake loading as seismic link yield level decreases due their exceptional behavior as well as its ability to undergo early plastic deformations achieving the concentration of inelastic deformation at tower horizontal beam.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.184-185
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• 2020

In Top-down sites, there are many open sections around the tower crane installed on the steel frame. The open section near the tower crane may cause slab cracks and deformation of the steel frame members installed in the open section due to earth pressure. Therefore, in the field, additional consideration during construction of the open section near the tower crane should be considered.