• Wind and Structures
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• v.12 no.4
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• pp.349-381
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• 2009

Since 1998, several institutions have deployed mobile instrumented towers to collect research-grade meteorological data from landfalling tropical cyclones. This study examines the wind flow characteristics from seven landfalling tropical cyclones using data collected from eight individual mobile tower deployments which occurred from 1998-2005. Gust factor, turbulence intensity, and integral scale statistics are inspected relative to changing surface roughness, mean wind speed and storm-relative position. Radar data, acquired from the National Weather Service (NWS) Weather Surveillance Radar - 1988 Doppler (WSR-88D) network, are examined to explore potential relationships with respect to radar reflectivity and precipitation structure (convective versus stratiform). The results indicate tropical cyclone wind flow characteristics are strongly influenced by the surrounding surface roughness (i.e., exposure) at each observation site, but some secondary storm dependencies are also documented.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.151-158
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• 2005

An important component of a cooling tower is an axial fan, and there happens distortion in its shape which brings significant loss of efficiency. In this paper, a surface profile measuring system for large size axial fan of cooling towers is developed. A laser sensor is used as a measuring device and aluminum profiles and stepping motors are engaged into the system as frame structure and driving devices respectively. The measuring data are compared to the design data to compute the distortion of the axial fans. Two types of errors, axial and twist errors, are used to represent the precision of axial fan distortion. Genetic algorithm is used to solve the optimization problem during computing the precision. Results are displayed three dimensionally in a solid-modeler as well as 2-D drawings to help users find it with ease.

• Wind and Structures
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• v.12 no.5
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• pp.401-412
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• 2009

A method is applied for the estimation of structural damage of tall slender structures using natural frequency and displacements measurements by GPS. The relationship between the variation in the global stiffness matrix (or in the stiffness of each finite element) and the change in the natural frequencies of the structure is given. In engineering practice the number of frequencies which can be derived by GPS measurement of long-period structures will be equal to one, two or three first natural frequencies. This allows us in initial studies to detect damage with frequency changes based on forward methods in which the measured frequencies are compared with the predicted analytical data. This idea, of health monitoring from possible changes to natural frequencies, or from a statement of excessive displacements is applied to the Stuttgart TV Tower.

• Wind and Structures
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• v.31 no.1
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• pp.1-14
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• 2020

This paper presents a method of estimation of fatigue demands on connection bolts of tubular steel wind turbine towers. The presented method relies on numerical simulation of aerodynamic loads and structural behavior of bolted connections modeled using finite element method. Variability of wind parameters is represented by a set of values derived from their probability densities, which are adjusted based on field measurements. Numerically generated stress time-series show agreement with the measurements from strain gauges inside bolts, in terms of power spectra and the resulting damage. Position of each bolt has a determining effect on its fatigue damage. The proposed framework for fatigue life estimation represents the complexities in loading and local behavior of the structure. On the other hand, the developed procedure is computationally efficient since it requires a limited number of simulations for statistically representing the wind variations.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.95.2-95.2
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• 2011

The most powerful technique for deducing the magnetic structure of the Sun is spectro-polarimetry. Detailed measurements of the polarization signal of the spectral lines (Stokes vector) allow us to infer the physical conditions in the solar atmosphere prevailing during the line formation. Inversion codes are the main tool to extract this information from the Stokes spectra. This study will focus on measurements of the chromospheric He I 1083.0 nm triplet and the photospheric Si I 1082.7 nm line. A spectropolarimetric data set of sunspots, obtained with the German Vacuum Tower Telescope (VTT) at the Teide observatory on Tenerife, is analyzed using an inversion technique. We will introduce the German Vacuum Tower Telescope and the inversion code HeLix, and will show data sets that are analyzed by HeLix.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.105-110
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• 1997

The need for special or high-rise building has made it necessary to fully understand the effects of wind forces on that. The objective of this study is to provide the information on the evalution of Wind-Induced Loads for the Inchon International Airport Traffic Control Tower Based on the results of this study, it can be found that the maximum base overturning moment getting by the dynamic model is higher than the static test one. And also, the assessment of serviceability comparing by the ISO-6897 is not appropriate. It is recommended that the reducing system of the wind-induced viberating is needed in this structure.

• International Journal of High-Rise Buildings
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• v.4 no.2
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• pp.135-142
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• 2015

As the skyscraper matures as a building type, its role in actively connecting to, and reinforcing, major threads of urban fabric becomes increasingly more important. The creation of public spaces inside of and adjacent to tall buildings allows for significant additions to the public realm, facilitating better connections between varied uses, providing needed access to critical transportation functions. In this more integrated version of the tall building type, the density afforded by a vertical structure is complemented by strategically devised porosity of plan and section. This paper examines three major tower projects which exemplify a progressive approach to permeable design: the recently completed Jingan Kerry Centre in Shanghai, the Lotte Supertower in Seoul, now half completed, and the One Vanderbilt tower being proposed next to Grand Central Terminal in New York City. These projects suggest possibilities for innovative approaches to private development strategies, public planning processes, and architectural design.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.265-268
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• 2005

This paper discusses a strategy and status for development and operation of durability mock-up test facilities for offshore structures. The strategy is examplified and facilitated using an offshore transmission tower crossing the West sea and the Shihwha lake, which was designed and constructed 345kV T/L lines transmitting power from Yeong-Heung fossil power plant to Seoul metropolitan area. Various data for corrosion protection, aging, life-prediction of concrete and steel offshore structures can be obtained using the proposed mock-up test facility. Acquired data will be used for further research on durability, life-prediction, and retrofit of structures. It is important to maintain the safety of 345 kV Yeong-Heung transmission line crossing the Shihwha lake because the offshore structure is one of the critical electric facilities transmitting large power to the metropolitan area. Operation of the offshore transmission tower mock-up is expected to make a significant contribution to stable power supply.

• Steel and Composite Structures
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• v.16 no.3
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• pp.289-303
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• 2014

In recent, development of construction and design technology gives taller, larger and heavier steel framed structures. With the tendency of increasing high-rise building, this study is strongly related to structural system, one of significant components in structural design. This study presents an innovative structural system, with high performance steel material, diagrid. Its detail, structural analysis, and structural experiments are all included for the development of new structures.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.151-159
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• 2016

Tower crane (T/C) is one of the major equipment that is highly demanded in construction projects. Especially, most high-rise building projects require T/C to perform lifting and hoisting activities of materials. Therefore, lifting plan of T/C needs to reduce construction duration and cost. However, most lifting plan of the T/C in construction sites has still performed depending on experience and intuition of the site manager without systematic process of rational work. Dependency structure matrix (DSM) is useful tool in planning the activity sequences and managing information exchanges unlike other existing tools. To improve lifting plan of T/C efficiently, this study presents a framework for the scheduling T/C using DSM through the case study in real world construction site. The results of case study showed that the scheduling T/C using DSM is useful to optimize the T/C lifting plan in terms of easiness, specially in the typical floor cycle lifting planning.