• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.5
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• pp.225-231
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• 2002

Many standards have Published for calculating of current carrying capacity for bare overhead conductors. Although these standards use the same basic heat balance concept, they use different approaches to calculate current carrying capacity, This paper looks at the four approaches used to calculate individual heat balance terms, at the overall impact of these terms on the current carrying capacity And this paper is proposed to the selection of proper standard and AC resistance within a country conditions for calculating the current carrying capacity of bare overhead conductors. So current carrying capacities are Proposed to some of conductors.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.65-70
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• 2012

The current-carrying capacities in IEC standards for underground refers to a soil thermal resistivity of 2.5[$K{\cdot}m/W$] where no measured data are available. But this value is considered too conservative and may not justifiable economically as to need precaution in using the value. In this paper, the standard practices on the application of soil thermal resistivity of some countries(UK, USA etc) are surveyed and proposed a reasonable representative value 1.0[$K{\cdot}m/W$] of soil thermal resistivity considering the domestic soil thermal properties with regard to the application of IEC standard.

• Structural Engineering and Mechanics
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• v.39 no.2
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• pp.287-301
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• 2011

This paper is focused on the residual capacity of steel columns, as a damage criterion. Load-Impulse (P-I) diagrams are frequently used for analysis, design, or assessment of blast resistant structures. The residual load carrying capacity of a simply supported steel column was derived as a damage criterion based on a SDOF computational approach. Dimensionless P-I diagrams were generated numerically with this quantitative damage criterion. These numerical P-I diagrams were used to show that traditional constant ductility ratios adopted as damage criteria are not appropriate for either the design or damage assessment of blast resistant steel columns, and that the current approach could be a much more appropriate alternative.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.35-43
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• 2012

In general, load carrying capacity, one of the load & resistance capacities in bridges, has more margins than the load carrying capacity evaluated with theoretical methods, unless there are severe damages, defects or material deterioration phenomena that can have a great impact on the behavior of bridges. However, errors have been already included in the current processes of loading tests and structural analysis for measuring load carrying capacity, thus devaluing the reliability of response adjustment factor. Therefore, this study found out the problems of existing electric resistance strain and displacement sensors in sensor suite to solve the problems with sensors and the errors in the appropriateness of structural analysis model, thereby leading to the changes into an optical fiber smart sensor with excellent performance. Besides, the study attempted to ensure the accuracy of response adjustment factor by selecting the optimal models through the interpretation of various structural analysis models.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.110-115
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• 2007

The localized rainfall happens frequently in urban areas recently and then, he drain pipes of urban areas do not drain well when the localized rainfalls happen. Specially, the inundation by the backwater on the lowland should be solved certainly in urban planning and sewer rehabilitation. In this study, it was examined whether the carrying capacities of the drain pipe are satisfied about a current design standard of the rainfall considering the outflows of the urban areas by the rainfall analysis. Also, the backwater in the drain pipe and the inundation on the lowland were analyzed considering the water level of the discharged river and the propriety of the design standard was examined by the analysis about the rainfall frequency. Also, the results offered the basic data to decide whether the detention reservoir should be established and the scale of the pump station.

• Smart Structures and Systems
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• v.3 no.3
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• pp.281-298
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• 2007

The load carrying capacity of a bridge needs to be properly assessed to operate the bridge safely and maintain it efficiently. For the evaluation of load carrying capacity considering the current state of a bridge, static and quasi-static loading tests with weight-controlled heavy trucks have been conventionally utilized. In these tests, the deflection (or strain) of the structural members loaded by the controlled vehicles are measured and analyzed. Using the measured data, deflection (or strain) correction factor and impact correction factor are calculated. These correction factors are used in the enhancement of the load carrying capacity of a bridge, reflecting the real state of a bridge. However, full or partial control of the traffic during the tests and difficulties during the installment of displacement transducers or strain gauges may cause not only inconvenience to the traffic but also the increase of the logistics cost and time. To overcome these difficulties, an alternative method is proposed using an excited response part of full measured ambient acceleration data by ordinary traffic on a bridge without traffic control. Based on the modal properties extracted from the ambient vibration data, the initial finite element (FE) model of a bridge can be updated to represent the current real state of a bridge. Using the updated FE model, the deflection of a bridge akin to the real value can be easily obtained without measuring the real deflection. Impact factors are obtained from pseudo-deflection, which is obtained by double-integration of the acceleration data with removal of the linear components on the acceleration data. For validation, a series of tests were carried out on a steel plategirder bridge of an expressway in Korea in four different seasons, and the evaluated load carrying capacities of the bridge by the proposed method are compared with the result obtained by the conventional load test method.

• Advances in concrete construction
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• v.3 no.4
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• pp.295-316
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• 2015

A bridge widening technology using steel-concrete composite system was developed and is presented in this paper. The widened superstructure system consists of a newly built composite steel-concrete girder with concrete deck and steel diaphragms attached to the existing concrete girders. This method has been applied in several bridge widening projects in China, and one of those projects is presented in detail. Due to the higher stiffness-to-weight ratio and the rapid erection of composite girders, this widening method reveals benefits in both mechanical performance and construction. As only a few methods for the design of bridges with different types of girders are recommended in current design codes, a more accurate analytical method of estimating live load distribution on girder bridges was developed. In the analytical model, the effects of span length, girder pacing, diaphragms, concrete decks were considered, as well as the torsional and flexural stiffness of both composite box girders and concrete T girders. The study shows that the AASHTO LRFD specification procedures and the analytical models proposed in this paper closely approximate the live load distribution factors determined by finite element analysis. A parametric study was also conducted using the finite element method to evaluate the potential load carrying capacities of the existing concrete girders after widening.

• Steel and Composite Structures
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• v.51 no.4
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• pp.417-440
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• 2024

Artificial neural networks (ANN) have been the focus of several studies when it comes to evaluating the pile's bearing capacity. Nonetheless, the principal drawbacks of employing this method are the sluggish rate of convergence and the constraints of ANN in locating global minima. The current work aimed to build four ANN-based prediction models enhanced with methods from the black hole algorithm (BHA), league championship algorithm (LCA), shuffled complex evolution (SCE), and symbiotic organisms search (SOS) to estimate the carrying capacity of piles in cold climates. To provide the crucial dataset required to build the model, fifty-eight concrete pile experiments were conducted. The pile geometrical properties, internal friction angle 𝛗 shaft, internal friction angle 𝛗 tip, pile length, pile area, and vertical effective stress were established as the network inputs, and the BHA, LCA, SCE, and SOS-based ANN models were set up to provide the pile bearing capacity as the output. Following a sensitivity analysis to determine the optimal BHA, LCA, SCE, and SOS parameters and a train and test procedure to determine the optimal network architecture or the number of hidden nodes, the best prediction approach was selected. The outcomes show a good agreement between the measured bearing capabilities and the pile bearing capacities forecasted by SCE-MLP. The testing dataset's respective mean square error and coefficient of determination, which are 0.91846 and 391.1539, indicate that using the SCE-MLP approach as a practical, efficient, and highly reliable technique to forecast the pile's bearing capacity is advantageous.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.425-436
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• 2014

Although the strut-tie model approaches of current design codes are regarded as the valuable methods for designs of structural concretes with D-regions, the approaches have to be improved because of the uncertainties in terms of the concepts and provisions for designs of 3-dimensional structural concretes. To improve the uncertainties, a new strut-tie model approach is proposed in this study. In the proposed approach, the concepts of employing a 3-dimensional grid element allowing load transfers in all directions at a node to construct a strut-tie model, a numerical analysis approach to determine the effective strengths of concrete struts and nodal zones by reflecting the effects of reinforcing bars and 3-dimensional stress state, and maximum areas of struts and ties to examine their load carrying capacities are integrated into the strut-tie model approaches of current design codes.

• Journal of Korea Entertainment Industry Association
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• v.14 no.7
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• pp.599-608
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• 2020

This study aims to investigate the performance and satisfaction of occupational therapists at the Dementia Relief Center for health care of the elderly in local communities, and to provide basic data necessary for role establishment by checking occupational therapists' tasks according to the priority. The subjects of this study were occupational therapists in dementia care centers in the Honam area and Gwangju Metropolitan City, who were surveyed via mail and e-mail. The survey had a total of 54 items covering the general characteristics of the therapists and current state of the centers (n=8), performance and satisfaction with the service areas and task content of the centers (n=45), and tasks that were considered important (one short-answer question). It was found that occupational therapists at the Dementia Relief Center were mainly carrying out the "Dementia Prevention Management Projects", which provided the programs for the patients, and they showed the highest satisfaction. Although the 'MMSE-DS' is occupational therapists' own area with high performance and satisfaction, it was not assigned to the occupational therapists at the Dementia Relief Center, indicating that the role was insufficient. The tasks related "administrative works and strengthening community capacities" showed low performance and satisfaction, but they are essential for the operation of the Dementia Relief Center and the management of the patients, so the plans to increase the occupational therapists' performance should be established. The categories of projects that occupational therapists consider important were also consistent with those they had to perform. It means the occupational therapists at the Dementia Relief Center recognized their unique roles. In this context, to establish the role of occupational therapist at the Dementia Relief Center, it is necessary to amend the operating guidelines based on the performance, satisfaction, and priorities of the projects, and to develop the curriculums and programs that can improve the tasks with insufficient performance and low satisfaction.