• Journal of the Korean Society of Safety
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• v.30 no.5
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• pp.37-43
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• 2015

This study examined the effects of the minimum horizontal load on the structural behaviors and safety of system supports. The minimum horizontal load was frequently ignored in the design of system supports even though the level of that load was specified in the code and guide in Korea such as 'Standard Specification in Temporary Construction' and 'Guide to Installation of Shores for a Concrete Bridge'. To examine the effects of considering the minimum horizontal load, the finite element analysis were performed for various system supports. By varying installing parameters of system supports such as the vertical member spacing, the installation height, and the thickness of slab, the maximum combined stress ratios were estimated to investigate the structural safety of system supports. The results showed similar axial stress in vertical members but an increase in bending stress with a consideration of the horizontal load. The combines stress ratios are remarkably increased due to the consideration of the horizontal load. Consequently, the system supports, which were initially estimated to be safe when only the vertical loads were considered, were changed to be unsafe in most cases by the effects of the both the vertical and horizontal stresses. Therefore, the minimum horizontal load following the code and the guide is an essential load that could control the structural safety of system supports.

• Journal of the Ergonomics Society of Korea
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• v.26 no.1
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• pp.39-46
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• 2007

The purpose of this study was to develop a comprehensive posture classification scheme considering the effects of external load and motion repetition as well as those of working posture. The scheme was developed based on a series of existing empirical studies dealing with postural classification scheme, effects of external load and motion repetition. Ranges of joint motions, external load and motion repetition were divided into the groups with the same degree of discomforts. Each group was assigned a numerical relative discomfort score of code on the basis of discomfort values for the neutral position of elbow flexion. The criteria for evaluating stress of working postures were proposed based on the four distinct action categories, in order to enable practitioners to apply appropriate corrective actions. The proposed scheme was compared with OWAS, RULA and REBA. The comparison revealed that while the proposed scheme and RULA showed similar results for the working postures with light external load and non-repetitive postures, the former overestimated postural load for postures with moderate or heavy external load and repetitive postures than the latter.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.3
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• pp.115-122
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• 2001

Bridge load rating calculations provide a basis for determining the load carrying capacity of bridges. Load rating requires engineering judgement in determining a rating value that is applicable to maintaining the safe use of the bridge and arriving at posting and permit decisions. Load testing is an effective means in calculating the rating value of bridge. In Korea, load carrying capacity of bridge is modified by response modification factor that is determined from comparisons of measured values and analysis results. This paper presents the development of a method for determining the response the modification factor, using traffic loads. The proposed method is based on the results of computer simulations of traffic action effects. The simulation program generates random traffic actions for defined traffic conditions and determines the frequency distribution of maximum traffic action effects. A comparison between the proposed method and the present method shows good agreement in estimating the modified load carrying capacity of bridges.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2203-2206
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• 2005

A load flow and short circuit fault simulation of AC electrified railway distribution systems is presented with DIgSILENT PowerFactory software. Load flow of electrified railways distribution system with concerning multi train lines and dynamic characteristics of train load is studied for different time laps. The dynamic characteristics of train load in starting and braking conditions with different starting and stopping times and its moving positions makes the load flow complicated so there is a great need in studying the effects of electrified railways on load flow. Short circuit fault transients is also studied and simulated for both power system or traction distribution system and their effects on the operation of the train sets is investigated.

• Computers and Concrete
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• v.11 no.5
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• pp.463-473
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• 2013

As known, concrete classes are described as strength of standard specimens produced and kept in ideal conditions, not including reinforcement and not subjected to any load effect before. Under the circumstances, transforming core strengths to the standard specimen strength is necessary and considering all parameters, affected on the core strength, is inevitable. In fact, effects of the reinforcement and the load history on concrete strength are generally neglected when these mentioned transforms are performing. The main purpose of this paper is investigating the effects of the reinforcement and the load history on the core strength. This investigation is experimentally performed on cores drilled from specimens having different keeping conditions, reinforced, unreinforced, subjected to bending and central pressure in various proportions of failure load during specified periods. Obtained results show that the importance of these effects cannot be neglected.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.4
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• pp.2445-2455
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• 1971

One-dimensional Consolidation tests with pore pressure measurement were caried in the ANTE-US consolidometer in order to investigate the effects of loading conditions on consolidation behavior of the soft clay. Undisturbed specimens of a sensitive clay were loaded in load-increment ratioes 0.5, 1.0 and 2.0, and load increment duration of 1, 6, 12, 24 and 48 hours with the application of 40 psi of back pressure. There is no significant effect of load-increment ratio on compression-pressure relationship, but the test with one-hour load increment duration doesn't represent the same results of the standard consolidation test in the sensitive clay.

• Educational Technology International
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• v.20 no.2
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• pp.137-168
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• 2019

This study examined the effects of information volume and distribution on learners' cognitive load and recall in a mobile augmented reality (AR) environment. Information volume refers to the degree of information users are provided in a learning task, while information distribution indicates the way in which information is distributed, either in a virtual or real format. Sixteen undergraduate students participated in the study, which employed a 2 × 3 randomized block factorial design with repeated measures. Information volume and distribution were independent variables, and factors in learners' cognitive load (mental effort, perceived ease of use, and perceived task difficulty) and recall test scores were the dependent variables. Information volume had significant main effects on perceived ease of use and task difficulty, and recall test scores, while information distribution had significant main effects on perceived task difficulty and test scores. A detailed discussion and implications are provided.

• Wind and Structures
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• v.5 no.1
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• pp.49-60
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• 2002

This paper describes a simple method for evaluating the design wind loads for the structural frames of circular flat roofs with long spans. The dynamic response of several roof models were numerically analyzed in the time domain as well as in the frequency domain by using wind pressure data obtained from a wind tunnel experiment. The instantaneous displacement and bending moment of the roof were computed, and the maximum load effects were evaluated. The results indicate that the wind-induced oscillation of the roof is generally dominated by the first mode and the gust effect factor approach can be applied to the evaluation of the maximum load effects. That is, the design wind load can be represented by the time-averaged wind pressure multiplied by the gust effect factor for the first mode. Based on the experimental results for the first modal force, an empirical formula for the gust effect factor is provided as a function of the geometric and structural parameters of the roof and the turbulence intensity of the approach flow. The equivalent design pressure coefficients, which reproduce the maximum load effects, are also discussed. A simplified model of the pressure coefficient distribution is presented.

• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.635-662
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• 2010

In this study, the effect of superstructure-abutment continuity on the distribution of live load effects among the girders of integral abutment bridges (IABs) is investigated. For this purpose, two and three dimensional finite element models of several single-span, symmetrical integral abutment and simply supported (jointed) bridges (SSBs) are built and analyzed. In the analyses, the effect of various superstructure properties such as span length, number of design lanes, girder size and spacing as well as slab thickness are considered. The results from the analyses of two and three dimensional finite element models are then used to calculate the live load distribution factors (LLDFs) for the girders of IABs and SSBs as a function of the above mentioned parameters. LLDFs for the girders are also calculated using the AASHTO formulae developed for SSBs. Comparison of the analyses results revealed that the superstructure-abutment continuity in IABs produces a better distribution of live load effects among the girders compared to SSBs. The continuity effects become more predominant for short span IABs. Furthermore, AASHTO live load distribution formulae developed for SSBs lead to conservative estimates of live load girder moments and shears for short-span IABs.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.12
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• pp.1514-1519
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• 1999

This paper presents two flexible alternatives to the decoupled load flow(DCL) method. The proposed load flow methods can improve the convergence profiles of the DCL by reflecting in part the effects of the off-diagonal terms in the Jacobian at minimal costs. They can improve the convergence characteristics especially when the power system operating states deviate from the conditions required for stable convergence of the DCL and the P-Q coupling becomes significant. Two algorithms are obtained from the expression of the full Newton-Raphson load flow (NRL) method by successively diminishing the effects of the off-diagonal submatrices in the Jacobian. In the process of simplification, the Neuman series expansion is utilized. Test results show promising performances of the proposed algorithms in their convergence characteristics both in number of iterations and overall convergence speeds. Proposed algorithms are expected to provide flexible alternatives to the NRL when the DCL experiences convergence problems.